Dr. Ngugi Mathew Piero

Graduated Students


PhD Biotechnology

Student Research Details
Student Research Details

Nzaro Gona Makenzi
PhD ( Biotechnology )
Areas of Interest: Plant Biotechnology
Email:makenzinzaro@gmail.com

Project Title: IN VITRO REGENERATION AND EVALUATION OF SALTSTRESS TOLERANCE OF SELECTED KENYAN SWEETPOTATO (Ipomoea batatas) GENOTYPES

Project Summary

Salinity affects about 40% of the global area mainly the arid and semi-arid regions. Moreover, 2% of the lands farmed by dry-land agriculture, and more than 20% of total irrigated acreage have already been damaged by salts worldwide. In Kenya the ASALs cover approximately 80% of the total area where agricultural production constraints include salinity and sodicity. Sweetpotato Ipomoea batatas L. (Lam.) is the third most economically important root crop after potato and cassava in the world cultivated for human consumption, animal feed and industrial uses. The production of sweetpotato is affected by abiotic stresses including salinity. However, data on levels of salinity tolerance among Kenyan sweetpotato genotypes is limited. The objective of the study was in vitro regeneration and evaluation of growth and salt tolerance among selected Kenyan sweetpotato genotypes. Fifteen Kenyan selected sweetpotato genotypes 36, Ksp 20, Ksp28, Kemb 36, Kemb 10, Kemb 23, Kalamb Nyerere, Mweu Mutheki, Enaironi, Mugande, Zambezi, SPK 004, SPK 013, Spk203 andJewel were used for the present study. Only seven genotypes were used for in vitro direct shoot organogenesis. Results shows that the highest number of adventitious bud; 8.00 (Kalamb nyerere) was producing in dark condition at 0.25 mg/l TDZ hormone level. Regeneration frequencies of adventitious buds recovered in the dark was the highest, 83.20% (Jewel) at 0.10 mg/l NAA hormone level. The best genotypes for direct shoot organogenesis were Kalamb nyerere, Kemb 36 and SPK 004. Growth analysis shows that the sweetpotato genotypes with the highest mean growth rates were Kalamb Nyerere, Spk203, Enaironi, and Mweu Mutheki. Sudden shock treatment was used for studying the effect of in vitro osmotic and salt stress on leaf photosynthetic pigment content in sweetpotato genotypes. Results show that at low in vitro osmotic and salt stresses all genotypes had reduced amount of photosynthetic pigments except. Best performing genotypes under in vitro osmotic and salt stress were Ksp 36, Ksp 28 and Zambezi. An in vivo incremental salt stress regime was used to identify tolerant sweetpotato genotypes using morphophysiological parameters. In the first month results shows that all the genotypes except a few had reduced photosynthetic pigments and growth parameters. However all genotypes had reduced parameters in the second month. Yield was negatively affected by in vivo salt stress but the reduction varied according to the genotypes tested. Using the combined approach the following genotypes were found to be salt tolerant Spk 004, Mweu Mutheki, Ksp 36, Kemb 36 and Kalamb Nyerere and can be incooperated in breeding programs so as to introgress tolerance to sensitive genotypes.


Purity Gacheri Limbua
PhD ( Biotechnology )
Areas of Interest: Plant Biotechnology
Email:cherimutuma@gmail.com

Project Title: REGENERATION AND Agrobacterium-MEDIATED INTROGRESSION OF ISOPENTENYL TRANSFERASE (IPT) GENE IN SELECTED KENYAN GROUNDNUT (Arachis hypogaea L.) GENOTYPES FOR DROUGHT TOLERANCE

Project Summary

Groundnut (Arachis hypogaea L.) is an important crop in terms of income and nutrition. The seeds are nutritional source of vitamin E, niacin, falacin, calcium, phosphorus, Magnesium, Zinc, Iron, ribloflavin, thiamine and potassium. It helps in reducing the risk in developing type II diabetes and cardiovascular disease. Despite its importance, groundnut yield is limited by environmental factors such as drought. The prediction of climate change indicate that drought will occur more often due to factors like global warming and this will reduce groundnut production thereby affecting its prices and the prices of its derived products such as groundnut butter. Strategies to the improvement of groundnuts towards drought tolerance have involved both genetic engineering (GE) and non-genetic engineering approaches such as marker assisted selection. Breeding is however laborious, lengthy and carries along undesired alleles. The objective of this work was to regenerate and genetically transform Kenyan groundnut genotypes with isopentenyltransferase (IPT) gene via Agrobacterium mediated transformation to enhance drought stress tolerance. The cotyledonary nodes of six Kenyan adapted Groundnuts genotypes (ICGV 12991, CG 7, Red Valencia, ICGV 90704, Chalimbana and JL 24) were transformed using Agrobacterium tumefaciens strain EHA 101 carrying PNOV-IPT binary vector containing an IPT gene which was driven by SARK promoter and terminated by TNOS terminator. The vector also contained phospomannose Isomerase enzyme (PMI) gene for selection of transformed tissues. Putative transformants were tested for presence of the transgene by PCR designed to amplify IPT gene sequence. Gene expression was confirmed by RT–PCR. Transformation frequency was calculated as a percentage of the number of putative transformants divided by the total number of infected cotyledonary nodes. This ranged from 9.87% for ICGV 90704 to 19.77% for JL 24.  Transformation efficiency was calculated as a percentage of the number of PCR positive plants divided by the total number of cotyledonary nodes infected. This ranged from 0% for ICGV 12991 and Chalimbana to 1.74% for JL 24. As a prerequisite for transformation, in vitro regeration protocol for ICGV 12991, CG 7, Red Valencia, ICGV 90704, Chalimbana and JL 24 groundnut genotypes was optimized using cotyledonary nodes explants. Vapor sterilization showed four hours as the optimal for obtaining clean viable explants. BAP 5 Mg/L combined with 1 Mg/L TDZ was the best concentration for optimal shoot induction. BAP at 5 Mg/L was the best for elongation of shoots and NAA at 1 Mg/L was the best concentration for rooting. The data suggest the possibility of transforming Groundnuts with ipt gene and regenerating normal transgenic plants. Future work should involve setting out drought stress assays for RT – PCR positive plants so as to determine the efficacy of IPT gene to confer drought stress tolerance under drought conditions. Other groundnut genotypes should also be transformed using ipt for drought tolerance.

PhD Medical Biochemistry

Student Research Details
Student Research Details

JOSEPH KIAMBI MWORIA
PhD ( Medical Biochemistry )
Areas of Interest: Neural Sciences (Pain, inflammation, fever)Phytomedicine and Drug discovery.
Email:kiambijoseph2013@gmail.com

Project Title: Phytochemical Profile, Antipyretic, Analgesic and Anti-Inflammatory Potential of Dichloromethane Leaf Extracts of Eucalyptus globulus (Labill) and Senna didymobotrya (Fresenius)

Project Summary

The study focuses on analysis of phytochemical composition of Eucalyptus globulus (Labill) and Senna didymobotrya (Fresenius) and their use as alternative and complementary medicine in management of pain fever and inflammation.


MAKORI WYCLIFFE ARIKA
PhD ( Medical Biochemistry )
Areas of Interest: Medical Biochemistry, Phytomedicine, and Drug Develpment
Email:arika.makori@ku.ac.ke

Project Title: PHYTOCHEMICAL PROFILE, ANTI-OBESITY, COGNITIVE ENHANCING, NEUROBEHAVIORAL AND ANTIOXIDANT EFFECTS OF DICHLOROMETHANE LEAF EXTRACT OF Gnidia glauca (FRESEN)

Project Summary

Obesity is a chronic metabolic disorder characterized by an excessive accumulation of fats in the body due to an imbalance between calorie intake and energy expenditure. The epidemic of obesity is currently on the rise probably due to increasingly sedentary lifestyles combined with easy availability of palatable, high fat foods. Globally, its prevalence has shown a startling increase in all age groups and has been associated with morbidity and mortality. Prescription of anti-obesity drugs can be useful adjuncts to diet and exercise for obese patients who have failed to achieve weight loss. However, these drugs are ineffective, not readily available, unaffordable and have been associated with adverse effects. Therefore, medicinal plants have drawn a sharp focus in recent times as complementary and alternative medicines owing to their biocompatibility, affordability and are assumed to be safe due to their long-term clinical application. Hereby, determination of therapeutic activities and identification of active principles from herbal prescriptions have become the prime focus in validation of their folkloric usage and in drug discovery programs. The present study aimed to determine phytochemical profile, anti-obesity effects, antioxidant properties, cognitive enhancing and neurobehavioral effects of dichloromethane leaf extract of Gnidia glauca. The phytochemical profile of Gnidia glauca was determined using Gas Chromatography linked with Mass Spectrophotometer (GC-MS). Obesity was experimentally induced by feeding the rats with prepared high-fat-diet (HFD) and water ad libitum for the period of 6 weeks. The in-vivo anti-obesity effects were determined by oral administration of G. glauca at dosage levels of 200, 250 and 300mg/kg body weight in HFD-induced obese rats from the 6th to 12th week. Determination of cognitive-enhancing effects of Gnidia glauca in HFD-induced obese rats was determined using Morris Water Maze experiment. The neurobehavioral effects of Gnidia glauca in HFD-induced obese rats were tested using Open Field Test. The spontaneous emitted behaviors determined included the locomotor activity, anxiety and exploration-like behaviors. The in vitro antioxidant potential and free radical scavenging activities of Gnidia glauca were determined using both enzymatic and non-enzymatic assays. The results indicated that Gnidia glauca leaf extract exhibited potent anti-obesity effects in HFD-induced obese rats. It significantly reduced the body weight, organ weights, organo-somatic indices, anthropometric indices, the total fat content, adiposity index, atherogenic index as well as the lipid profiles (Triglycerides, Total Cholesterol, Low Density Lipoproteins and Very Low-Density Lipoproteins). However, it significantly increased levels of High-Density Lipoproteins. The extract increased levels of white blood cells, differential leucocyte counts, platelet count as well as red blood cells and related parameters. The leaf extract of Gnidia glauca resulted in an improved hippocampal dependent spatial learning and memory retention in HFD-induced obese rats. Moreover, it showed anxiolytic effects, increased spontaneous locomotor activity and exploration-like behaviors in HFD-induced obese rats. Gnidia glauca indicated in vitro antioxidant effects in all the tested non-enzymatic assays. The GC-MS analysis revealed the presence of 28 bioactive compound in Gnidia glauca. The anti-obesity effects, antioxidants activities, cognitive enhancing effects and the improved spontaneous emitted behaviors observed could be attributed to the phytochemical compounds present in the plant extract. The present study therefore, scientifically validated the traditional use of this plant and generated data that can serve as an evidence to recruit Gnidia glauca as a potential candidate for the synthesis of new, effective and affordable drug against obesity and its associated complications. However, there is need for bioassay-guided fractionation of active compounds in Gnidia glauca. Besides, it is recommended to conduct comprehensive toxicity studies to establish the safety profiles of Gnidia glauca.

 


PhD Biochemistry

Student Research Details
Student Research Details

Masters Biotechnology

Student Research Details
Student Research Details

Jedidah Wangari Mwangi
Masters ( Biotechnology )
Areas of Interest: Plant Molecular Genetics and Breeding.
Email:mwangijedidah@gmail.com

Project Title: Phenotypic and Molecular Characterization of Vigna radiata(L) Wilckzek (Mung bean) in SelectedCounties in Kenya.

Project Summary

Mung beans is a nutri-rich legume that is classified under Neglected and Underutilized Crops This study therefore aims at characterizing mung bean genotypes and identify their diversity, both phenotypically and genotypically. This will aid in breeding programs for better and improved mung bean varieties.


Stephen K. Mwihia
Masters ( Biotechnology )
Areas of Interest: Medical Biotechnology
Email:mwihiask32@gmail.com

Project Title: IN VITRO ANTIBACTERIAL AND ANTIOXIDANT ACTIVITIES OF METHANOLIC AND DICHLOROMETHANOLIC SEED EXTRACTS OF KENYAN ANNONA SQUAMOSA LINN

Project Summary

The study aimed at investigating the efficacy of the methanolic and dichloromethane seed extracts of Annona squamosa (Linn) used ethnomedically the communities in Wang’uru area of Kirinyaga County, Kenya to treat enterobacterial infections. Furthermore, the antioxidant potential of these extracts to manage oxidative stress, which is a consequence of heavy bacterial load, was evaluated. In addition, qualitative screening of phytoactive complexes was performed. The studied seed extracts exhibited significant In vitro antibacterial and antioxidant properties. Moreover, the extracts demonstrated presence of phytochemicals, which were considered responsible for the antibacterial and antioxidant effects.


Boniface Maina Mwangi
Masters ( Biotechnology )
Areas of Interest: Medical Biotechnology
Email:mwangi.bonifacemaina@gmail.com

Project Title: Evaluation of Antinociceptive and Antiinflammatory Properties of Dichloromethane: Methanolic Extracts of Caesalpinia volkensii and Maytenus obscura in Rats Models

Project Summary

Kibiwott Scolar Jepkorir
Masters ( Biotechnology )
Areas of Interest: Medical Biotechnology
Email:scolarbiwott@gmail.com

Project Title: Antioxidant Activity of Dichloromethane and Methanol Blend Extracts of Carissa edulis and Caesalpinia volkensii in Alloxan-induced Diabetic Rats

Project Summary

Free radicals cause imbalance between antioxidants and oxidants in the human body leading to oxidative stress. Normally, oxidative stress is considered as the main cause many diseases and aging. However, synthetic antioxidants are expensive and associated with a lot of side effects. Antioxidant phytochemicals are found in many medicinal plants and play important role in prevention and treatment of diseases linked with oxidative stress as they possess free radical scavenging abilities. Hence there is need to develop herbal agents that are efficient, affordable and with fewer side effects. Carissa edulis and Caesalpinia volkensii have been used through ages by herbalists in many parts of the world to treat various ailments. Although these medicinal plants have been widely used traditionally in treating diseases associated with oxidative stress, there is limited literature to validate their use. This study therefore sought to determine the ethnobotanical efficacy of C. volkensii and C. edulis as alternatives for the management of free radical- causing diseases. Generally, the extracts exhibited good antioxidant activity when compared with the standard (Ascorbic acid). However, the root bark extracts of C. edulis showed better reducing power activity (0.88mg/ml), DPPH radical scavenging activity (82.13%) and hydrogen peroxide scavenging ability (84.31%)  than the leaf extracts of C. volkensii (0.83mg/ml, 75.8% and 74.49% respectively). In addition, C. edulis showed higher total phenolics and flavonoid contents than C. volkensii. The phenol content for C. edulis and C. volkensii extracts were 146.5±3.28 mg /g and 126.0±1.50 mg/g respectively. On the other hand, the flavonoid contents were 91.33±3.51 mg/g and 46±3.0 mg/g, for C. edulis and C. volkensii respectively. In general, the results obtained from both plant extracts were concentration dependent. Qualitative phytochemical screening results showed the presence of saponins, phenolics, terpenoids, alkaloids and flavanoids


GITAHI STEPHEN MAINA
Masters ( Biotechnology )
Areas of Interest: Medical Biotechnology
Email:gitahism@gmail.com

Project Title: Antipyretic and Antinociceptive Properties of Dichloromethane:Methanolic Leaf and Root Bark Extracts of Carisa edulis (Forssk.) Vahl in Rats

Project Summary

Conventional medications are expensive, not easily available and arguably associated with various severe adverse effects hence the need to develop herbal agents that are effective as a complement. Carissa edulis (Forssk.)Vahl is the herb
that has previously made thousands of people flock to a remote Loliondo village in Northern Tanzania, for its cure said to apply to all diseases such as cancer, HIV/AIDS, ulcers, hypertension, and diabetes. Although C. edulis (Forssk.)Vahl
is widely used for pyrexia and pain in the traditional system of medicine, review of the literature show no scientifically investigated report of its described effects. This study was therefore designed to bioscreen the dichloromethane: methanolic
extract of the leaf and root bark of C. edulis on antipyretic and anti-nociceptive potential on rats. The plant parts were collected from Siakago-Mbeere north subcounty, Embu County, Kenya. Experimental rats were divided in to four groups;
normal group, diseased negative control group, diseased reference group and diseased experimental groups. Pain was induced experimentally using formalin while pyrexia was induced into the rats using turpentine. The experimental groups
were treated with leaf and root bark extracts at concentration of 50mg/kg, 100mg/kg and 150mg/kg. Antipyretic and anti-nociceptive activities in rats were compared with aspirin (100mg/kg) and diclofenac (15mg/kg) as the standard
conventional drugs, respectively. The leaf extracts reduced the rectal temperature by between 0.02% - 2.98% while the root bark extracts reduced it by between 0.15% - 2.55%. Aspirin reduced the elevated rectal temperature by between
1.08% - 2.53%. For antinociceptive study, the leaf extract reduced pain by between 47.04% - 47.19% (in the early phase) and 38.96% - 89.26% (in the late phase) while the root bark extracts reduced it by between 21.5% - 41.89% (in the
early phase) and between 21.4% - 90.62% (in the late phase). Diclofenac reduced pain by between 27.37% - 34.9% (in the early phase) and 88.24% - 90.28% (in the late phase). Further, the phytochemical screening results showed that the
extracts had alkaloids, flavonoids, steroids, saponins, phenolics and tepenoids. Alkaloids, flavonoids, and saponins have been associated with antipyretic and anti-nociceptive activities. Therefore, the study has established that the DCM:
methanolic extracts of C. edulis (Forssk.)Vahl are effective in management of fever and pain.Therefore C. edulis can be explored as a possible bio-resource for generating an easily available herbal formulation that is more effective in the
treatment of fever and pain.


Celestine Anyango Ochola
Masters ( Biotechnology )
Areas of Interest: Medical Biotechnology
Email:celestochola09@gmail.com

Project Title: Antibacterial Effects of Methanolic Leaf Extracts of Acacia ataxacantha and Pilostigma thonningii

Project Summary

Bacterial infections can become life-threatening, if not properly treated, causing millions of deaths worldwide. More than half of these deaths occur in the African continent. There is rise in bacterial infections due to increased human population, HIV infections and re-emergence of previously harmless micro-organisms. The discovery of antibiotics in 1940s removed the threat of these infections on human life. However, conventional antibiotics are inefficient, considerably costly and have adverse side effects. Moreover, limited health facilities are constrained and several bacteria have developed antibacterial resistance raising fear of mankind returning back to pre-antibiotic era. There is still hope even if antibiotics completely fail. Medicinal plants possess bioactive compounds which can provide the best alternative source to obtain new, safe, affordable and accessible antibacterials. It is important to take a fresh look at plants in a bid to discover new effective antibiotics. Acacia ataxacantha and Piliostigma thonningii are indigenous plants used by the Mbeere community to treat various infections but lack scientific data to confirm their activities. This study investigated the in vitro antibacterial activities of of the two plants extract against S. aureus ATCC 29213 and B. subtilis clinical isolate, E. coli ATCC 25922, S. typhi ATCC 1408 and S. flexneri ATCC 12022. The antimicrobial assays included disc diffusion, Minimum Inhibitory Concentration (MIC) and Bactericidal Concentration (MBC); Gentamycin and DMSO as reference positive and negative control respectively. Both the extracts of P. thonningii and A. ataxacantha inhibited the growth the studied bacterial pathogens producing Mean Zones of Inhibition (MZI) ranging from 6.33±0.33 to 19.00±0.58 mm and 6.33±0.33 to 17.00±0.58 mm respectively. The MZI, MIC, MBC were statistically significant at p<0.05. Gentamycin inhibited the growth of the bacteria at a lower concentration while DMSO showed no activity against all the bacteria. The values obtained from MBC assays were higher than those of MIC assays. Qualitative phytochemical analysis showed the presence of saponins, steroids, alkaloids, flavonoids, terpenoids, phenols and tannins which could be responsible for the observed antibacterial activities.  The extracts of P. thonningii and A. ataxacantha exhibited a broad spectrum antibacterial activities in a concentration dependent manner hence confirm their usage in folk medicine. There was no significant difference in the antibacterial activities of Acacia ataxacantha and Piliostigma thonningii. The extracts were bactericidal against S. aureus, B. subtilis, S. flexneri and S.typhi while they were bacteriostatic against E. coli. The plants therefore, provide hope for a source of new antibacterial agent. The current study, therefore, recommends the ethnomedicinal and therapeutic use of P. thonningii and A. ataxacantha in treatment and management of bacterial infections after further comprehensive study of their toxicity and safety profiles.


Mwangi Elias Kihara
Masters ( Biotechnology )
Areas of Interest: Agricultural/Microbial Biotechnology
Email:enmkiharah@gmail.com

Project Title: Effects of Selected Carrier Materials and Storage Temperatures on Survival, Viability and Efficacy of Rhizobia Biofertilizers

Project Summary

This study evaluated the effects of selected carrier materials and storage temperatures on survival, viability and efficacy of selected rhizobium strains used in rhizobia biofertilizers. Four selected carrier materials (peat, filter mud, cassava peels and Yeast Extract Mannitol (YEM) broth, five storage temperatures (-20 °C, 4 °C, 25 °C, 30 °C and 40 °C) were used to study the survival of two  rhizobium strains (Bradyrhizobium Spp. USDA 110 and 532c). Biological and physicochemical properties of the carrier materials were determined before inoculating them with a known amount of rhizobium CFUs. The inoculated carrier materials were stored in different temperatures for six months. Samples from the carrier materials were taken after every two weeks and CFUs determined. The viability of rhizobia inoculants for the best carrier material after six months was determined under greenhouse conditions using soybean as the test crop. Presence of both fungal (except in peat) and bacterial contaminants was observed in the carrier materials hence the carriers were s sterilized before being used. The rhizobia population decreased over time regardless of carrier material and storage temperature. The population reduction was highest at 40 °C and lowest at 4 °C except in peat and YEM where reduction was lowest at -20 °C. The initial cell population and the cell population at the end of experiment (6 months) were significantly different (P<0.05). After six months storage, results revealed that rhizobia CFUs was retained above the required threshold of 107 CFU/g at -20 °C and 4 °C across all carriers. At 25 °C, strains populations were retained above threshold for about 5 months. Similarly, at 30 °C and 40 °C both strain population were retained above required threshold for about 4 months. The effect of storage temperature between the two strains on nodule fresh weight was significantly different (P<0.05). Nodule effectiveness across storage temperatures were higher than that of control, although, inoculation did not have significant difference on nodules effectiveness across all temperatures and storage duration. The average %Ndfa for soybean ranged between 33.37 and 49.84 for 532c and 32.31 and 52.57 for USDA110. These values were higher (P > 0.005) than that of control across all treatments which averaged at 23.25. Nodule occupancy across the storage temperature ranged between 73-100% and 70-100% for 532c and USDA110, respectively except for 532c fulltime (40 °C) which was 30%. The result showed that a bigger number of nodules analyzed were occupied by the rhizobium strains inoculated indicating viability of both 532c and USDA110 after storage for six months. Selection of the best rhizobia inoculants formulations, specific storage temperatures, and rhizobia strains adaptable to local conditions are essential. The findings of this study showed filter mud and cassava peels were able to retain the highest rhizobia number. Moreover, sterilization of carrier materials is essential and the shelf life of biofertilizers in the market should be based on availability of storage conditions at farm level.


Mwangi Peter Nthiga
Masters ( Biotechnology )
Areas of Interest: Medical Biotechnology
Email:nthigapete@gmail.com

Project Title: ANTIPYRETIC AND ANTINOCICEPTIVE PROPERTIES OF METHANOLIC EXTRACTS OF Harrisonia abyssinica Oliv. AND Landolphia buchananii (Hallier f.) Stapf IN ANIMAL MODELS

Project Summary

The study aimed to evaluate the antipyretic and antinociceptive effects of their methanolic extracts. The plant samples were sourced from Siakago-Mbeere north sub-county, Embu County, Kenya. Experimental rats and mice were divided into four groups; normal group, a negative control group, reference group and experimental groups. The experimental groups were treated with stem bark extracts at concentration of 50mg/kg, 100mg/kg and 150mg/kg. The formalin paw licking test was used to determine the antinociceptive potential while evaluation of antipyretic activities was determined by using 20% turpentine solution as the pyrexia inducing agent. Evaluation of the antipyretic and antinociceptive activities was compared with aspirin and diclofenac as the reference drugs respectively. Harrisonia abyssinica extract reduced the rectal temperature by between 0.90% - 1.73% while L. buchananii extract reduced it by between 0.32% - 2.52%. Aspirin reduced the elevated rectal temperature by 1.70% - 2.32%. For antinociceptive study, the H. abyssinica extract reduced pain by 39.73% - 81.13% (in the early phase) and 15.92% - 69.84% (in the late phase) while L. buchananii extract reduced it by between 35.35% - 47.72% (in the early phase) and 20.57 - 55.17% (in the late phase). In the early phase, diclofenac reduced pain by 19.97% - 46.50% and 76.77-74.80% (in the late phase). Qualitative phytochemical screening results showed that the extracts possessed alkaloids, flavonoids, steroids, saponins, phenolics and terpernoids. Saponins, flavonoids and alkaloids have been associated with antipyretic and antinociceptive activities. The results of the study have validated the folklore use of the aforementioned plants in the suppression of pyrexia and pain.


Rose Chemutai Lagat
Masters ( Biotechnology )
Areas of Interest: Biotechnology
Email:oselagat76@gmail.com

Project Title: Physicochemical Characterization and Selected Quality Trait-Based Genetic Diversity Studies on Selected Kenyan and Tanzanian Rice (Orya sativa L.) Varieties

Project Summary

Audrey Chepkemoi
Masters ( Biotechnology )
Areas of Interest: Medical Biotechnology
Email:caudrey015@gmail.com

Project Title: ANTIINFLAMMATORY, ANTINOCICEPTIVE AND ANTIPYRETACTIVITIES OF ACETONE STEM BARK EXTRACTS OF Pappea capensis Litchi IN ANIMAL MODELS

Project Summary

Persistent inflammation, pain and fever are sensory afflictions that lead to emotional discomfort and unnecessary suffering to human beings thereby, affecting all the daily life activities. These disorders are usually suppressed with anti-inflammatory, analgesic and antipyretic drugs. However, conventional medications are arguably associated with a number of side effects. It is thus necessary to develop alternative agents, which are more effective, cheaply available, and with insignificant side effects. Currently, herbal agents are becoming popular due to the reduction of the efficiency of conventional medicine. Pappea capensis has been used locally by the Embu community as folklore remedy for various common ailments including inflammation, pain and fever. However, no data has been documented on organic stem bark extracts of Pappea capensis in the management of these conditions. Therefore, this study examined anti-inflammatory, antinociceptive and antipyretic activities of acetone stem bark extract of Pappea capensis in mice and rat models. The plant samples were obtained from Mbeere North, Embu County, Kenya. Active components were extracted using acetone solvent. Experimental animals were grouped into four, the normal control group, reference control group, negative control group and three experimental groups. The pain was stimulated experimentally using formalin, 20% turpentine was used to induce fever whereas inflammation was induced using carrageenan. Diclofenac sodium was used as reference drug to treat pain and inflammation, while aspirin was used as reference drug for inflammation. All treatments were administered intraperitoneally. Data were expressed as mean ± SEM. Difference between the means of different groups was analyzed using one-way ANOVA followed by Tukey’s post hoc test. Unpaired student t-test was used to compare the mean activities of pain inhibition between the two phases. Values of P≤0.05 were considered significant. The P. capensis extract reduced the paw edema by between 97.34% - 84.47%. Diclofenac reduced the paw edema by between 94.64% - 86.79%. The stem bark extract of P. capensis inhibited pain by between 48.9% - 63.4% in the early phase and between 25.48% - 52.88% in the late phase. The reference drug reduced pain in the two phases by between 51.5% - 54.8%, respectively. The P. capensis extract lowered pyrexia by between 99.66%-92.90%, while aspirin, reduced pyrexia by between 97.15% - 91.75%. Phytochemical bio-screening results revealed that the acetone extracts of P. capensis had phenolics, flavonoids, terpenoids, steroids, alkaloids and saponins that have been associated with anti-inflammatory, antinociceptive and antipyretic properties. This study, therefore, showed potent anti-inflammatory, antinociceptive and antipyretic activities of acetone extract of P. capenesis. Hence, P. capensis can be explored as a possible bio-resource for generating readily available herbal formulation that is effective in the management of inflammation, pain and fever.


Aliyu Umar
Masters ( Biotechnology )
Areas of Interest: Medical Biotechnology
Email:umaraliyu971@gmail.com

Project Title: EVALUATION OF ANTI – APHIDS PROPERTIES OF THE AQUEOUS CRUDE FRUIT SAP EXTRACT OF Solanum incanum

Project Summary

The green peach aphid, Myzus persicae is a worldwide aphid species which is responsible for important economic losses. Its feed on more than 50 plant families, causing great losses to agro industrial crops, vegetables, horticultural crops and stone fruits and it is presently categorized as one of the most important agricultural pests worldwide. Conventional insecticides used for aphids control are expensive and arguably associated with various severe adverse side effects hence the need to develop botanical pesticides that are effective as alternative. Solanum incanum is a perennial, wild shrub like herb that belongs to family Solanaceae, which grows in many regions of Africa, Middle East and Far East Asia. Though S. incanum fruits sap has been used by the local farmers to control aphids, review of the literature show no scientifically investigated report of its effectiveness and the mode of its insecticidal action. This study was therefore designed to evaluate anti-aphids properties of crude fruit sap extract of S. incanum and its possible inhibition of acetylcholinesterase enzyme in green peach aphids. A total of 180 kales plants were planted in the Plant Transformation Laboratory of Kenyatta University. They were divided into six groups with 10 plants each. Each group was subjected to routine spray with 10, 25, 50 and 75% S. incanum extract. Group five was sprayed with dimethoate and the last group was sprayed with water. The number of live and dead aphids was counted with the help of hand lens for two weeks after every spray in each group with an interval of one day to determine the deterrent and insecticidal activity. Acetylcholinesterase inhibition was determined using Ellman method. The S. incanum extracts at different concentrations tested showed insecticidal and deterrent activities against green peach aphids. The extract also inhibited the acetylcholinesterase of the green peach aphids at a dose dependent manner and IC50 of 49.9 was calculated. Further, phytochemical screening results showed that the crude fruits sap extract of S. incanum have phytochemicals associated with insecticidal and deterrent activity. The study has established that the crude fruits sap extract of S. incanum are effective in managing insects‟ pest.


James Kamau Kimani
Masters ( Biotechnology )
Areas of Interest: Medical Biotechnology
Email:jameskimani006@gmail.com

Project Title: Antipyretic and Antiinflammatory Properties of Methanolic Extracts of Kigelia africana and Acacia hockii in Rat Models

Project Summary

Pyrexia and inflammation cause discomfort, suffering and lower productivity of the victims. Non-steroidal anti-inflammatory drugs which are highly prescribed in medication of pyrexia and inflammation have been reported to possess adverse effects. Herbal medicines may possess bioactive compounds that are safer and efficient in the management of various diseases and disorders. Kigelia africana and Acacia hockii are traditionally used to manage pyrexia and inflammation among the Embu and Mbeere communities in Kenya but there lacks scientific data to support their use. The present study determined antipyretic and anti-inflammatory activities of the two extracts in animal models to scientifically confirm their traditional use. The plant samples were collected with the help of local herbalists in Embu County, Kenya and transported to Kenyatta University for cleaning, air drying, milling, and extraction in Biochemistry and Biotechnology laboratories. Animal models were randomly divided into six groups of 5 animals each; three experimental groups (50, 100 and 150mg/kg body weight), normal control group, negative control group and positive control group. The antipyretic effect was determined using turpentine-induced pyrexia, while the anti-inflammatory effect was determined using carrageenan-induced hind paw edema method. The antipyretic and anti-inflammatory activities of the extracts were compared to reference drugs aspirin and diclofenac respectively. The stem bark extract of K. africana reduced the elevated rectal temperature by between 0.06 and 3.07 percent, while the stem bark extract of A. hockii reduced the raised rectal temperature by between 0.62 and 3.88 percent. The aspirin reduced the rectal temperature of pyretic rats by between 0.63 and 3.1 percent. The leaf extract of K. africana reduced inflamed hind paw diameter of mice by between 0.21 and 4.98 percent, while the stem bark extract of A. hockii reduced inflamed hind paw diameter by between 0.6 and 5.38 percent. The diclofenac reduced inflamed hind paw diameter by between 1.11 and 4.9 percent. The qualitative phytochemical screening indicated the presence of flavonoid, alkaloids, steroids, saponins, terpenoids, phenolics, and cardiac glycosides. The present study demonstrated potent antipyretic and anti-inflammatory activities of methanolic extracts of K. africana and A. hockii in a dose-dependent manner, which supports their traditional use. The present study, therefore, recommends that K. africana and A. hockii may be used as a potential candindate in development of antipyretic and anti-inflammatory agents.


Rachael Wambua Kitondo
Masters ( Biotechnology )
Areas of Interest: Medical Biotechnology
Email:wambuarachel@gmail.com

Project Title: IN VITRO ANTIBACTERIAL ACTIVITIES OF DICHLOROMETHANE- METHANOLIC EXTRACTS OF Croton megalocarpus Hutch, Strychnos henningsii Gilg and Psorospermum febrifugum Spach

Project Summary

Pathogenic bacteria cause infectious diseases that affect many life forms. Antimicrobial agents have played a significant role in reducing mortality and morbidity associated with human infectious diseases. However, due to emergence of multi drug resistant bacteria, the side effects associated with antibiotics and the high cost of antimicrobial drugs, management of bacterial infections has become difficult in developing countries. Herbal medicines are easily accessible with minimal side effects. They therefore provide an alternative in the management of bacterial infections. Croton megalocarpus, Strychnos henningsii and Psorospermum febrifugum are medicinal plants used to treat bacterial infections traditionally. The aim of this study was to determine the antibacterial activities of dichloromethane-methanolic extracts of these plants against human pathogenic bacteria. Stem barks of C. megalocarpus and S. henningsii and roots of P. febrifugum were collected from Mwingi Sub-county of Kitui County and transported to Kenyatta university laboratory.  The plant samples were dried under shade then ground into fine powder and extracted using dichloromethane-methanol (1:1). Crude extracts from the plants were screened against five strains of bacteria: - Esherichia coli ATCC 25922, Salmonella typhi ATCC 19430, Bacillus subtilis ATCC 6051, Shigella flexneri ATCC 700930 and Staphylococcus aureus ATCC 25923 obtained from department of Biochemistry, Microbiology and Biotechnology, Kenyatta University. Antibacterial susceptibility tests were done using disc diffusion method. 6 mm sterile discs were impregnated with different extract concentrations and then placed on Mueller Hinton agar plates inoculated with the bacterial strains. The plates were incubated at 370C for 24 hours. The activity was determined by measuring the zones of inhibition in millimeters. Data was analyzed using one- way ANOVA and expressed as mean and standard error of mean. Generally, S. henningsii stem bark extract had the highest inhibitory activities, producing the lowest MIC values ranging between 9.38 mg/ml and 37.50 mg/ml. This could have been due to wide range of phytochemicals. B. subtilis and S. aureus were the most sensitive bacteria to the extracts. The antibacterial activities of the extracts were found to be much lower compared to the reference drug Ciprofloxacin. The qualitative   phytochemical analysis of the extracts revealed presence of bioactive components such as tannins, alkaloids, saponins, sterols, phenols, flavonoids and terpenoids, which are associated with antibacterial properties. The results provide support for the use of plants in traditional medicine.


EMMA NYANGANYI MARIGI
Masters ( Biotechnology )
Areas of Interest: Plant Biotechnology
Email:emmamarigi@yahoo.com

Project Title: REGENERABILITY AND TRANSFORMABILITY OF SELECTED KENYAN FARMER PREFFERED CASSAVA (Manihot esculenta Crantz) ECOTYPES

Project Summary

Cassava (Manihot esculanta Crantz) is a perennial shrub grown mainly for its tuberous roots and provides food for over 500 million people in developing countries. The crop is affected by various biotic and abiotic stresses such as diseases, low protein content and presence of cyanogenic glycosides that result in low production. Management strategies against these stresses rely upon conventional improvement programs, but these are not effective owing to vast limitations inherent to such breeding programs. Genetic engineering may allow rapid development of stress-resistance in cassava, but efficient and robust transformation and regeneration protocols for farmer-preferred cultivars need to be optimized for ease of transfer of novel genes since existing regeneration and transformation protocols are not compatible with all the cultivars/ecotypes. In this study, the ability of coastal cassava ecotypes Karembo, Tajirika, Kibanda meno mkubwa and Ex-Mariakani to regenerate via somatic embryogenesis was investigated. Two types of explants (immature leaf lobes and stems) were cultured on Murashige and Skoog (MS) medium supplemented with varying concentrationsof auxins; 2,4-dichloro phenoxyacetic acid (2,4-D), picloram and α-naphthalene acetic acid (NAA), a cytokinin; 6-Benzylaminopurine (BAP) and a gibberellin (GA3) under 16 hour light/8 hour darkness and total darkness photoperiod regimes. Transformability of the regenerable ecotypes was also investigated through Agrobacterium-mediated transformation with the β-glucuronidase (gus) reporter gene. The results show that 2,4-D performed better than picloram in inducing callus across the ecotypes under both photoperiod regimes. There were significant differences (P≤0.05) in frequencies of somatic embryogenesis among the cassava ecotypes. Generally, 2,4-D produced the highest somatic embryogenesis frequencies of >92% (Kibanda meno mkubwa), >83% (Ex-Mariakani), >82% (Karembo) and >85% (Tajirika) under total darkness. All the four ecotypes recorded successful maturation of somatic embryos induced using immature leaf lobes on media with different phytohormone combination ratios. On the other hand, only stem explants of ecotypes Karembo and Kibanda meno mkubwa matured into cotyledons and germinated into whole plants. Molecular analysis by PCR confirmed transformation of the putative transormants from the four ecotypes. From this study, an optimized and reproducible transformation and regeneration protocol for four Kenyan cassava ecotypes has been developed.


CHRISTINE NAKHUMICHA WANYONYI
Masters ( Biotechnology )
Areas of Interest: Plant Biotechnology
Email:tnakhumicha@gmail.com

Project Title: IN VITRO REGENERABILITY AND TRANSFORMABILITY OF SELECTED KENYAN CASSAVA (Manihot esculenta CRANTZ) GENOTYPES

Project Summary

Cassava (Manihot esculenta Crantz) is a valuable source of calories especially in countries where malnutrition is widely spread and ranks fourth as a source of food calories, after rice, maize and wheat. Cassava is a root crop that is rich in starch but low in protein and is widely used as food, animal feed and raw material in industries. Some of its undesirable traits include susceptibility to diseases and pests, high cyanogenic glucoside content, low protein content in roots and low shelf life after harvest. Attempts to improve these traits in cassava by conventional breeding face challenges of high outcrossing, high heterozygosity and low fertility. Therefore, the application of genetic transformation to introduce agronomically useful traits would greatly compliment classical breeding approaches. The objective of this study was to determine the regenerability and test for transformability of selected Kenya cassava genotypes. Three genotypes (Ex-ndolo, Karibuni and Shibe) were collected from coastal and eastern agroecological zone based on their traits which are high yielding and early maturity and maintained at the Kenyatta University Plant Transformation Laboratory glasshouse. Sterile plants were established in vitro and maintained on media containing Murashige and Skoog salts with vitamins, (30g/l sucrose and 3.0g/l gel rite) and used as source of explants. Picloram and 2, 4-D were used to induce somatic embryos using leaf and stem explants. The results indicated callus induction varied between 82.67-86.3% for picloram and 6].41 -78.13% for 2,4- dichlorophenoxyacetic acid (2, 4-D) for concentrations 4mg/l, 6mg/l, 8mg/1 and lOmg/1 using stem and leaf explants while varying the photoperiod. Somatic embryo frequency was 31.95-81.48% for leaf explants and 19.65-42.83% for stem explants. Embryogenic calli was matured on media supplemented with different concentration of 6-Benzylaminopurine, c-naphthaleneacetic acid and gibberellic acid before being transferred to regeneration media. Ex-Ndolo was highly responsive to the maturation media and formed shoots when the embryos originated from leaf explants for both 2, 4-D and picloram were matured. There were significant differences in GUS assay frequencies between experiment done after infection and that done after eight weeks in all the three genotypes when subjected to Agrobacterium tumefaciens-mediated transformation. The results from this study provide a platform for scientists to introgress genes of agronomic interest.


Berick Moturi Sieberi
Masters ( Biotechnology )
Areas of Interest: Medical Biotechnology
Email:bericksm@gmail.com

Project Title: IN VITRO ANTIBACTERIAL ACTIVITIES OF DICHLOROMETHANE: METHANOLIC EXTRACTS OF Fuerstia africana, Polygala sphenoptera AND Centella asiatica AGAINST SELECTED BACTERIA PATHOGENS

Project Summary

Bacterial infections are responsible for a large number of deaths every year worldwide. On average, 80% of the African populations cannot afford conventional drugs.  Moreover, many synthetic antibiotics are associated with side effects and progressive increase in antimicrobial resistance. Currently, there is growing interest in discovering new antibacterial agents from ethno-medicinal plants. About 60% of the population living in developing countries depends on herbal drugs for healthcare needs. This study involved screening of three medicinal plants commonly used by herbal medicine practitioners in Kisii county to treat symptoms which may be related to bacterial infections. Standard bioassay methods were applied throughout this study. They included preliminary screening against human pathogenic bacteria strains using Agar Disc Diffusion, broth micro-dilution method and Time kill kinetics with tetracycline as a positive control. Phytochemical screening was carried out to determine the presence or absence of different classes of compounds in the crude extracts. Data was analyzed using one way ANOVA, and means separated by Tukey’s test. Specifically, dichloromethane: methanolic (DCM:MeOH) extracts of Fuerstia africana, Polygala sphenoptera and Centella asiatica were screened against five (5) human pathogenic bacteria strains (Salmonella typhi ATCC 19430, Escherichia coli ATCC 25922, Shigella sonnei ATCC 25931, Bacillus subtilis ATCC 21332 and Staphylococcus aureus ATCC 25923). The extracts showed strong antibacterial effects ranging between 13.00mm and 19.00mm. The results of minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of the extracts showed good activities of between 15.63 and 31.25mg/ml in some test cultures. However, Bacillus subtilis ATCC 21332 and Staphylococcus aureus ATCC 25923 were least sensitive. Time kill kinetics studies of the extracts showed dose and time dependent kinetics of antibacterial properties. Phytochemical screening of DCM:MeOH extracts revealed the presence of alkaloids, flavonoids, phenolics, terpenoids, cardiac glycosides, saponins, steroids,  and tannins. The present study indicates that the tested plants can be an important source of antibacterial agents and recommends that the active phytoconstituents be isolated, identified and screened individually and in different blends for activities (for possible synergistic effects) and also subjected to further for in vivo and toxicological studies.

 


SYOMBUA EASTER DAVID
Masters ( Biotechnology )
Areas of Interest: Plant Biotechnology
Email:syox08@gmail.com

Project Title: OPTIMIZATION OF REGENERATION AND AGROBACTERIUM-MEDIATED TRANSFORMATION PROTOCOLS FOR SELECTED KENYAN CASSAVA (Manihot esculenta Crantz) GENOTYPES

Project Summary

Cassava (Manihot esculenta Crantz) is a tropical root crop that serves as a staple food and a vital source of income to small holder farmers in the tropics. Despite its contribution to food security, cassava production and utilization is faced by several challenges that include post-harvest physiological deterioration, insect and disease susceptibilities and accumulation of cyanogenic glycosides. Cassava crop improvement by conventional breeding has failed to address these constraints because of unsynchronized flowering, lack of resistance genes, high heterozygosity, allopolyploidy and poor seed set. Genetic transformation which begins with the establishment of embryogenic callus cultures can be used as one of the ways to complement these challenges faced by cassava breeders. This study investigated the effects of explant source (immature leaf lobes and meristematic stem segments), auxins (2, 4-dichlorophenoxyacetic acid (2, 4-D) and picloram), and photoperiod (0/24 and 16/8 light/ dark) on callogenesis and embryogenesis in five African cassava genotypes (KME 1, 08/080, 08/354, 08/274 and TMS 60444). Callus formation and embryogenesis were successfully achieved in both
explant sources. The leaf explants recorded significantly higher frequencies (p < 0.05) of somatic embryogenesis compared to the stem explants in all the five genotypes. This study showed that the 0/24 light/ dark photoperiod was superior to the 16/8 light/ dark cycle for both callogenesis and embryogenesis. Although statistically insignificant, 8 mg/l 2, 4-D was the best concentration for the induction of embryogenesis in 08/354, TMS 60444, 08/274 and 08/080 while 10 mg/l gave the best results for genotype KME 1. For picloram, 10 mg/l showed the best results for embryogenesis across all genotypes.
This study also determined the effects of varying formulations of BAP (6-Benzylaminopurine), NAA (α-Naphthalene acetic acid) and GA3 (Gibberellic acid) on somatic embryo maturation and plant recovery of the selected cassava genotypes
Embryos in the cotyledonary stage were incubated in maturation medium supplemented with five different combinations of plant growth regulators: BAP, NAA, and GA3. Significant differences (p < 0.05) were recorded in shoot formation frequencies with combination 2 mg/l BAP, 0.01 mg/l NAA, 1.5 mg/l GA3 and combination 1 mg/l BAP, 0.02 mg/l NAA, 1.5 mg/l GA3 giving the highest rates. Transformability was determined by carrying out a histological GUS (β-glucuronidase) assay on callus transformed using Agrobacterium tumefaciens strain EHA 101 harbouring plasmid pTF 102 with a GUS visual marker gene and a bialaphos selectable marker gene. All the genotypes were found amenable to Agrobacterium mediated transformation with TMS 60444 and 08/274 recording the highest transformabilities of 73.33 % and 68.33 % respectively. A positive
polymerase chain reaction (PCR) amplification targeting the GUS gene confirmed the transfer of the transgenes into cassava cells. The validated regeneration and transformation protocols reported here can be used for the integration of desired traits in African cassava genotypes.


Lilian Ngithi
Masters ( Biotechnology )
Areas of Interest: Population Genetics
Email:loisengithi@gmail.com

Project Title: PHENOTYPIC AND GENETIC DIVERSITY OF KHAT (Catha edulis VahL) VARIETIESGROWN IN MERU AND EMBU COUNTIES, KENYA

Project Summary

Khat(Catha edulis Vahl) is an evergreen shrub habitually ingested for its euphoric and stimulatory effects. Despite the daily use and consumption of khat by millions of people in Kenya, little is known aboutboth phenotypic and molecular diversityof what is viewed as cash crop of growing importance. This study aimed at evaluating the genetic and phenotypic diversity of sampled khat cultivarsgrown in Embu and Meru counties.The collection was done in Embu and Meru counties in Mt.Kenya region. Phenotypic characterization was done by measuring 13 khat traits among 30 khatsamples. For genotypic characterization, DNA extraction was done using CTAB method and genetic diversity determined using 5 SSR markers. MINITAB 17 Software was used for description of principal component and construction of dendrogram using the Eucledian distance tool where 58.7% variability was observed among 13traits studied in 30 samples of khat (Catha edulis) and the phenotypes grouped into 2 clusters by the dendrogram. Power Marker version 3.25 was used to determine the major allele number, genetic diversity and Polymorphic information content (PIC).The number of alleles per locus ranged from 2 to 4 with an average of 2.4 alleles across the 5 markers used. Gene diversity per locus ranged from 0.2296(CE50) to 0.3344 (CE64) with an average of 0.2883 and Polymorphic information content (PIC), ranged from 0.2024(CE50) to 0.2878(CE37) and an average observed across all the markers with an average of 0.2475 per locus. GenAlEx version 6.5 was used to determine the principal coordinate analysis (PCoA) and analysis of molecular variance (AMOVA). A two dimensional scatter plot was generated and the two PCoA axis accounted for 43.33 and 28.19% of genetic variation. The AMOVA indicated intra-population variation of 93% while inter-population variation was 7%. DARwin 6.0.12 software was used to determine the genetic dissimilarity matrix based on Jaccard’s coefficient and to draw an unweighted neighbour joining tree. Pairwise genetic dissimilarity matrix of 30 khat individual samples ranged from 1.000 to 0.0000. Several khat samples had similarities as an indication that they shared closer ancestry compared to other cultivars. The unweighted neighbour joining tree clustered the khat cultivars into three major clusters and subsequent sub-clusters hence effectively differentiating Mt. Kenya regionkhat. From the results, molecular and phenotypic characterization proved to be useful tools for discrimination of various khat cultivars of C.edulis. Phenotypic diversity showed considerable variability based on 13 khat traits.This study revealed that there is a considerable level of genetic diversity among the Mt. Kenya khat cultivars grown in Embu and Meru counties and this is indicated by the high number of alleles and the clusters generated. The study recommends that the SSR markers be used to construct a genome database that will be useful in khat breeding programmes and characterization of khat cultivars.

Masters Medical Biochemistry

Student Research Details
Student Research Details

MORIASI GERVASON APIRI
Masters ( Medical Biochemistry )
Areas of Interest: Neurology; Clinical Biochemistry; Biochemical Pathology; Pharmacology and Toxicology; Phytomedicine; Natural Products Research and Drug Discovery; Cell Physiology; Molecular Biology; Oncology
Email:gmoriasi67@gmail.com

Project Title: Cognitive Enhancing, Antioxidant Activities Aqueous and Methanolic Extracts of Piliostigma thonningii (Schum.) and Lonchocarpus eriocalyx (Harms.)

Project Summary

The study aimed at investigating the efficacy of the aqueous and methanolic stem bark extracts of two medicinal plants (Piliostigma thonningii (Schum.) and Lonchocarpus eriocalyx (Harms.) used ethnomedically by the Mbeere people of Embu County, Kenya to treat cognitive deficits. Furthermore, the antioxidant potential of these extracts to thwart oxidative stress, which is the main driver of neurodegeneration and cognitive impairment, was evaluated. Additionally, qualitative phytochemical screening of phytoactive principles was performed.The studied plant extracts exhibited remarkable cognitive-enhancing activities in scopolamine-induced cognitively-impaired mice. Moreover, the studied plant extracts demonstrated ex vivo and in vitro antioxidant potencies, which were considered responsible for the cognitive-enhancing effects. Additionally, antioxidant-associated phytochemicals were detected in the studied plant extracts, which undoubtedly played significant roles in ameliorating cognitive impairment in experimental mice.


Beatrice Muthoni Guchu
Masters ( Medical Biochemistry )
Areas of Interest: Medical Biochemistry, Natural products,
Email:bintimuthoni@gmail.com

Project Title: In vitro antioxidant activities of methanolic extracts of Caesalpinia volkensii, Acacia hockii and Vernonia lasiopus

Project Summary

Caesalpinia volkensii, Acacia hockii and Vernonia lasiopus are medicinal plants used in traditional medicine around the world in the management of oxidative stress-related disorders. The present study aims to determinein vitro antioxidant effects as well as phytochemical composition of methanolic leaf extracts of Caesalpinia  volkensii, Vernonia lasiopus and stem bark extracts of Acacia hockii thus, validating their traditional use in management of oxidative stress related disorders.


Jorum Humphrey Obel
Masters ( Medical Biochemistry )
Areas of Interest: Medical Biochemistry
Email:jorumobel@yahoo.com

Project Title: Effects of Dichloromethane: Methanolic Leaf Extracts of Carissa edulis (forsk.) Vahl on Hematological and Serum Lipid Profiles in Rat Models

Project Summary

Duncan Maina Kariuki
Masters ( Medical Biochemistry )
Areas of Interest: Medical Biochemistry
Email:dmainarh@gmail.com

Project Title: In Vivo Safety of Dichloromethane: Methanolic Extracts of Allium sativum in Rat Models

Project Summary

Joseph Kiambi Mworia
Masters ( Medical Biochemistry )
Areas of Interest: Medical Biochemistry
Email:kiambijoseph2013@gmail.com

Project Title: Determination of antinociceptive activity of acetone leaf extracts of Caesalpinia volkensii and Carissa spinarum in mice models

Project Summary

Despite the progress that has occurred in recent years in the development of therapy, there is still a need for effective and potent analgesics for pain. Pain is defined as unpleasant feeling essential for body’s defense system. Pain is managed using analgesics such as aspirin,paracetamol, diclofenac, morphine, opioids, among others. Conventional antinociceptives are expensive and have many side effects. Continued use of these drugs may lead to tolerance. Medicinal plants have been used to relieve pain and form a better alternative. Herbal antinoceptives are affordable and have arguably fewer side effects. Carissa spinarum (Linn) is used to treat rheumatoid pain, fever and inflammation related disorders. Caesalpinia volkensii (Harms) has pharmacological activities that include antimicrobial,immune modulatory properties and antimalarial. These two plants are used locally by people in Embu County as analgesics.This study was designed to bioscreen the acetone leaves extracts of C. volkensii (Harms) and C. spinarum (Linn) for anti-nociceptive potential. The plant parts were collected from Siakago-Mbeere north sub-county, Embu County, Kenya. The samples were prepared and extraction of the active compounds carried out using organic solvent acetone in the ratio1:2.Swiss albino mice were divided into five groups of five mice each: Normal, negative, reference and experimental group. Pain was induced experimentally using formalin and acetic acid. The experimental groups were treated with 50 and 100mg/kg dose quantities of each plant extracts prepared. The acetone leaves extracts of the two plants were evaluated for antinociceptive properties in mice compared to the reference drug diclofenac sodium. Mice were injected intraperitoneally with doses of the herbs, diclofenac and the vehicle. Thirty minutes later the animals were injected with 0.01ml of 2.5 % formalin in the sub planter region of the left hind paw and the other set with 0.4ml of 5% acetic acid. The total time spent lifting; biting, licking the paw and writhing were counted and scored. The acetone leaves extracts lowered paw licking time in a dose dependant manner, The leaf extracts of C.volkensii at the dose levels of 50and 100mg/kg body weight reduced the formalin-induced pain in mice by 72.74% and 99.38 % respectively and acetic acid writhing by levels of 50 mg/kg body weight reduced the number of writhes by 81.40%, 100 mg/kg body weight did not reduce writhing. C.spinarum at the dose levels of 50mg/kg and 100mg/kg body weight reduced formalin induced pain by3.47%and 34.46 and 20.2% and 95.50% respectively. Acetic acid induced pain in mice by 73.77 % and 86.89 % respectively. Diclofenac reduced the pain by 15.34 in early phase and 98.02% in late phase. Further, the phytochemical screening results showed that the acetone leaves extracts of C.volkensii (Harms) and C.spinarum (Linn) have phytochemicals associated with anti-nociceptive activities. The study has established that the acetone leaves extracts of C.spinarum (Linn) and C.volkensii (Harms) are effective in management of pain. It is therefore recommended that further fractionation of the metabolites of the two plant extracts be carried out with a view to identifying the most active compounds for further development into drugs for management of pain.


Ndile Michael Musila
Masters ( Medical Biochemistry )
Areas of Interest: Medical Biochemistry
Email:2mmusila@gmail.com

Project Title: In Vivo Toxicity of Methanolic Extracts of Caesalpinia volkensii (Harms) and Vernonia lasiopus (O. Hoffman) in Rat Models

Project Summary

This study was designed to evaluate the in vivo toxicity of methanolic leaf extracts of both plants  in Wistar rats. The two medicinal plants were collected in Mbeere region in Kenya. In evaluating the acute toxicity, limit test was used. Sub-acute toxicity of the two plants was also evaluated in line with OECD guidelines. Signs of toxicity were observed and weight of the animals recorded after every 7 days, for four weeks. On the 29th day, the animals were sacrificed and blood drawn through cardiac puncture for hematological analysis, renal and liver function tests. Weight of internal organs (Brain, lungs, liver, spleen and kidney) was recorded. In acute toxicity, no death resulted from administration of the plant extracts. In sub-acute toxicity studies, there was significant difference in body weight between the days, within the groups. However, there was no significant difference in body and organs weight among the groups treated with the plants extract relative to the control. Treatment with methanolic leaf extract of C. volkensii at dose of 1000 mg/kg body weight resulted in significant increase in total bilirubin and aspartate aminotransferase (P˂0.05). In addition, 100 mg/kg body weight resulted in significant decrease in sodium, hemoglobin and hematocrit, although the values were within normal reference range in rats. Total protein was significantly low in all the groups treated with V. lasiopus, nevertheless, the values were also within the normal range. On the other hand, albumin was significantly low at extract dose of 1000 mg/kg body weight. Furthermore, there was significant neutropenia, lymphocytosis and thrombocytosis in the group administered with 1000 mg/kg body weight of V. lasiopus extracts (P˂0.05). Qualitative phytochemical screening of both medicinal plant extracts confirmed the presence of alkaloid, flavonoids, tannins, phenols and terpenes. It was therefore concluded that the median lethal dose (LD50) of two plant extracts was greater than 2000 mg/kg body weight. In sub-acute toxicity, the extracts slowed weight gain in rats at a dose of 1000 mg/kg body weight. In addition, extracts at 1000 mg/kg body weight resulted in hematotoxicity and hepatotoxicity. 


Onyango Kenneth Osano
Masters ( Medical Biochemistry )
Areas of Interest: Medical Biochemistry
Email:osanokenneth032@gmail.com

Project Title: In vivo Toxicity of Dichloromethane and Methanol Leaf Extracts of Prosopis juliflora

Project Summary

DANIEL MUTHEE GAICHU
Masters ( Medical Biochemistry )
Areas of Interest: Medical Biochemistry
Email:danielgaichu2016@gmail.com

Project Title: Antipyretic and Antiinflammatory Potential of Dichloromethane: Methanolic Leaf and Stem Bark Extracts of Ximenia americana in Laboratory Animals

Project Summary

Wilhelmy Marion Jebet
Masters ( Medical Biochemistry )
Areas of Interest: Phytomedicine and Biopesticides
Email:marionjebet@yahoo.com

Project Title: Bioefficacy of Organic Extracts of Fish Poison Bush (Gnidia glauca, Fresen) Against Cowpea Weevil (Callosobruchus maculatus, Fabricius)

Project Summary

Cowpea weevil (Callosobruchus maculatus) is a major pests of stored cowpea in the tropical region of the world. In Kenya, the damage caused by Callosobruchus maculatus impacts negatively on its economic and nutritional values. The widely adopted use of chemical pesticides is marred with health and environmental hazards. Global concern about the use of synthetic chemicals has led to heightened restrictions and limitations on their use. This, therefore, has prompted the search for alternatives to synthetic pesticides. Gnidia glauca has been exploited by local people in control of post-harvest pests. However, no scientific research has been undertaken to evaluate its potential anti-insect properties. This study was therefore designed to gather preliminary data that can be used to develop a bio-insecticide to control C. maculatus. Four G. glauca organic extracts, methanol, ethyl acetate, DCM and blend (methanol, ethyl acetate, DCM and blend in ratio 1:1:1) were evaluated for contact toxicity, oviposition deterrence, inhibition of progeny emergence and repellency against cowpea weevil. The plant leaves were collected from Siakago-Mbeere, Embu County, Kenya. The samples were prepared, extracted and investigation carried out under ambient laboratory conditions. The experimental design entailed five test concentrations (2g/100ml, 4g/100m, 6g/100ml, 8g/100ml, and 10g/100ml) of each extract, the untreated control, the solvent control and the positive control. Each bioassay had four replications. Adult weevils (1-3 days old) were exposed to the extracts and mortality was monitored daily for the first four days. Subsequently, oviposition deterrence was assessed on the 15th day while inhibition of progeny emergence was evaluated on the 49th-day post-treatment. Extract repellency was assessed for the first 6 hours after treatment. Screening for plants phytochemicals was conducted using the standard recommended procedures. The results of this study revealed all G. glauca extracts, to a varied extent, induced mortality on C. maculatus. Mortality was concentration and exposure time dependent. Highest mortality of 89.74% was recorded with 10g/100ml ethyl acetate extract 96 hours post-treatment. The extracts significantly deterred oviposition with the 10g/100ml concentration of ethyl acetate, DCM and blend statistically (p>0.05) comparable to the activity of synthetic pesticide. All the extracts were found effective in inhibition of progeny emergence. 10g/100ml ethyl acetate extract demonstrated the highest inhibition of 99.3% while the least inhibition of 9.03% was exhibited by 2g/100ml methanol extract. G. glauca extracts proved to be attractant of C. maculatus rather than repellant, none of the extract concentration attained repellency greater than 50%. Results also showed that the extracts had tannins, phenols, flavonoids, terpenoids, saponins, alkaloids, cardiac glycosides and steroids which have been associated with insect control properties. It was therefore concluded that the plant extracts, possess bioactivity against Callosobruchus maculatus on the tested parameters of contact toxicity, oviposition deterrence, inhibition of progeny emergence and repellency. Hence the studied extracts can further be purified and developed into the plant-derived bio-pesticides.


Kenedy W. Wafula
Masters ( Medical Biochemistry )
Areas of Interest: Medical Biochemistry
Email:kenwaf@gmail.com

Project Title: IN-VITRO ANTIOXIDANT ACTIVITIES OF DICHLOROMETHANE EXTRACTS OF Strychnos henningsii G. AND Ficus sycomorus L.

Project Summary

Most of biochemical reactions in our body generates Reactive Oxygen Species (ROS), which are involved in the pathogenesis of oxidative stress-related disorders like diabetes, nephrotoxicity, cancer, cardiovascular disorders, inflammation and neurological disorders when they attack biochemical molecules like proteins, lipids and nucleic acid. Antioxidants are used to protect the cells or tissues against their potential attack by ROS. Natural based antioxidants such as catalase, glutathione, superoxide dismutase, vitamin C and E in the body are known to quench free radicals. Most medicinal plants possess a rich source of antioxidants such as flavonoids, phenols, tannins, alkaloids among others. These phytochemiclas are currently pursued as an alternative and complimentary drug. Strychnos henningsii and Ficus sycomorous are used in Africa traditional medicine for treatment of various ailments including rheumatism, syphilis, gastro intestinal pain, snake bites, abdominal pain diabetes as well as anaesthology, healing of wounds and as a mouth antiseptic. This study was designed to evaluate in-vitro antioxidant activities of Dichloromethanolic leaf extract of S. henningsii and stem bark extract of F. sycomorus using spectrophotometry method against 1,1-diphenly-2-picrylhydrazyl (DPPH), Hydrogen peroxide and Ferric reducing power assays. The antioxidants activities were assayed against ascorbic acid as a reference drug. Total flavonoids and phenolic compound were determined by Folin–Ciocalteu reaction. The results obtained showed both extracts significantly (p<0.05) exhibited good antioxidants activities at different concentrations used. The DCM leaf extract of S. henningsii and stem bark extract of F. sycomorus scavenge hydrogen peroxide radicals (H2O2) in a dose dependent manner. The half maximal percentage inhibition (IC50) of S. henningsii and F. sycomorus was 0.325 mg/ml and 0.330 mg/ml respectively. The two extracts also scavenged DPPH in a dose dependent manner.  Their IC50 value was 0.068mg/ml for S. henningsii and 0.062mg/ml for F. sycomorus. Both DCM leaf and stem bark extract of S. henningsii and F. sycomorus were found to have strong ferric reducing power in a dose dependent manner. The total phenolic content of DCM stem bark extract of F. sycomorus was higher than the leaf extract of S. henningsii. However, the total flavonoid content of S. henningsii was found to be higher than that of F. sycomorus. Preliminary phytochemical screening showed that both extracts possess saponins, flavonoids, phenols, steroids and alkaloids. Cardiac glycoside and terpenoid were tracely found in F. sycomorus but were absent in S. henningsii. Therefore, the results in this study showed both extracts possess secondary metabolites which are associated with antioxidants activities. The present study therefore recommends their usage in management of oxidative stress-related disorders.


Juma Kelvin Kisaka
Masters ( Medical Biochemistry )
Areas of Interest: Immunopathology, drug discovery and pharmacotoxicity
Email:juma.kelvin85@gmail.com

Project Title: EFFECTS OF Urtica dioica, Cucurbita pepo and Spinacea oleracea EXTRACTS IN AMELIORATION OF ALCOHOL INDUCED TOXICITY IN RAT MODELS

Project Summary

The study is on the effects of alcohol at both acute and chronic doses and the impact of damage to the kidneys, liver, spleen, pancrease and blood and how they can be managed using bioactive compounds from locally available vegetables and compared to the use of corticosteroids such as prednisolone and a commercially used herbal remedy, Silymarin. The study also explores the immunopathological pathways of cytokines modulations in alcohol induced tissue damage.


Phillip Einstein Ogola
Masters ( Medical Biochemistry )
Areas of Interest: Ionizing Radiations and Bioremediation (Environmental Biochemistry)
Email:phileinst@gmail.com

Project Title: DETERMINATION OF BACKGROUND IONIZING RADIATION IN QUARRIES AND PREMISES AROUND NAIROBI COUNTY

Project Summary

More recently, exposure to background ionizing radiations by the public is increasingly becoming a concern especially their contribution to the rising cancer incidences in Kenya. Such background ionizing radiations occur naturally from the sun, in rocks and soil and can cause changes in human cell including genetic mutation thus leading to cancer. Unfortunately, majority of the buildings in Kenya are usually constructed using stones and sand mined from underground rocks and river beds yet Kenya is not adequately radio-profiled to determine the levels of embedded radio-nuclides capable of emitting ionizing radiations. Conventionally, the World Health Organization (WHO) recommends that the annual exposure to the ionizing radiation to the general public should not exceed 1 mSv. This project therefore, sought to determine the levels of indoor background radiation in selected human premises and quarries around Nairobi County. Calibrated Radiation AlertR (Digilert 200) handheld radiation detectors were used to capture the reading. The meters were held at the abdominal level (about 1 m above ground level) and readings were recorded in mR/h for all quarry sites and premises. Numerical data was subjected to analysis of variance using Minitab version 17.0 to determine the statistical differences of exposure levels within various areas. A total of 38 quarries were designated Q 01 to Q 38 and 400 premises were sampled. The results showed that in Ndarugo area, Q09 had the highest annual dose threshold of 1.32 mSv while Q07 had the lowest annual dose threshold of 0.91 mSv. For quarries in other parts of Nairobi County, Q23 had the highest annual dose threshold of 1.68 mSv while Q34 had the lowest annual dose threshold of 1.06 mSv. Of the 38 quarries sampled in this study, only 5 quarries had annual exposure levels below the recommended WHO standard representing a dismal 13% compliance. There were significant differences in annual dose levels between the quarries sampled in the study (p≤0.05 was statistically significant). The annual indoor readings were highest in Eastleigh (4.070 mSv) and relatively lowest in Nairobi Central Business District (CBD) at 2.763 mSv, representing a deviation from WHO recommended standard of 307.0% and 176.3%, respectively. None of the premises sampled had exposure levels below the WHO recommended standard of 1 mSv. Overall, these results indicate presence of higher levels of ionizing radiations in quarries and premises beyond the acceptable annual threshold thereby posing significant health risk to the public. Consequently, these results could find great application in guiding the formulation of the national building code to include routine surveillance of the background ionizing radiation levels in quarries and in various buildings to assess the health risk of quarry workers and general public as well as exploring appropriate mitigation approaches.

Masters Biochemistry

Student Research Details
Student Research Details

Samson Koech Cheruiyot
Masters ( Biochemistry )
Areas of Interest: Biochemistry
Email:koechsam22@gmail.com

Project Title: Analgesic, Antipyretic and Anti-inflammatory Potential of Dichloromethane Root Extract of Clutia abyssinica in Rats and Mice Models

Project Summary

Various diseases and injuries are always presented with pain, fever and inflammation. These are considered as symptoms associated with various pathological processes in an animal body. Drugs that are used to alleviate pain, fever and inflammation such as non-steroidal anti-inflammatory drugs exhibit adverse effects for example cardiac abnormalities, peptic ulcers, liver toxicity and kidney failure. Therefore, there is need to come up with alternative remedies. Herbal medicines are deemed to be safe, have good efficacy and have fewer side effects. Clutia abyssinica is a shrub that is found in East, Central, and South Africa and it has been used traditionally to cure several ailments including malaria, chest pain, gonorrhea, fever, infertility, pain, inflammation, skin diseases and cancer. Roots of this medicinal plant have been used traditionally to prepare decoctions. The aim of the project was to evaluate the analgesic, antipyretic and anti-inflammatory potential of dichloromethanolic root extract of Clutia abyssinica in animal models. Plant sample material was collected from Kaptebee village, Turbo sub-county in Uasin Gishu County Kenya, and the active components extracted using dichloromethane. Pain, fever and inflammation were induced Swiss albino mice and Wistar albino rats using acetic acid, turpentine and carrageenan respectively. Swiss albino mice and Wistar albino rats were grouped into normal control, negative control, positive control and 3 experimental groups. Extracted root extracts were administered intraperitoneally to Swiss albino mice and Wistar albino rats at predetermined doses (50, 100, and 150 mg/kg body weight). The analgesic and anti-inflammatory activities of the plant root extract were compared to diclofenac the (reference drug) while the antipyretic activity was compared to aspirin. The dichloromethanolic root extract of C. abyssinica demonstrated significant analgesic, antipyretic and anti-inflammatory activities. Number of abdominal writhing was reduced between 33.95-49.51% by dichloromethanolic root extract while the diclofenac (reference drug) reduced abdominal writhing by 46.51%. Reduction in number of abdominal writhings by the extract indicates the plant posse’s analgesic properties. The elevated temperature was reduced between 0.68-3.34% by the dichloromethanolic root extract while Aspirin the (reference drug) reduced elevated temperature between 3.32-4.96%. Edema was reduced between 0.88-5.34% by the plant extract while diclofenac reduced edema between 2.21-5.35% respectively. Rectal temperature and the size of the edema was reduced more in the third and fourth hours signifying better blockage of mediators responsible for fever and inflammation.  Data was analyzed using one way analysis of variance followed by turkey’s test. Qualitative phytochemical analysis revealed the presence of alkaloids, flavonoids, terpenoids, steroids, saponins and cardiac glycosides. The extract from Clutia abyssinica may be used as an alternative bioresource in development of analgesic, antipyretic and anti-inflammatory agent. The study therefore, confirms the folklore use of the medicinal plant by Kalenjin community of Kenya to manage pain, fever and inflammation.


Jane Bosibori Maoga
Masters ( Biochemistry )
Areas of Interest: Biochemistry
Email:janeykemunto@gmail.com

Project Title: In Vitro Antioxidant Effects of Dichloromethane:Methanolic Extracts of Clutia abyssinica and Maytenus obscura

Project Summary

Oxidative stress is a state of imbalance between free radicals and antioxidants in the body. It is the main cause of several disease conditions such as diabetes, different types of cancers, cardiovascular diseases, inflammation and aging. Oxidative stress is managed by use of antioxidants which can be obtained in the diet or given as supplements. Antioxidants are substances with the ability to prevent oxidation of other molecules in the body by free radicals. Antioxidants react with free radicals making them stable and reducing their ability to react with different cell components. The treatment of oxidative stress has been confined to use of synthetic supplements, which are unaffordable to most Kenyans and are known to possess side effects. This has led to increased demand for herbal products with antioxidant properties that have little side effects, are affordable and more readily available. Different plants that are used as medicinal plants have been tested for antioxidant activity such as Strychnos henningsii and Rosemarinus officinalis. Clutia abyssinica and Maytenus obscura though traditionally used, have not been scientifically proven and documented. This study evaluated the in vitro antioxidant potential of Dichloromethane: Methanolic extracts of Clutia abyssinica and Maytenus obscura. Different antioxidant assays were done including free radical scavenging activity by using 1,1 –Diphenyl-2-Picrylhydrazyl (DPPH), total ferric reducing power and hydrogen peroxide scavenging activity. The DCM: MeOH extracts of both plants demonstrated a significant level of DPPH scavenging activity with the highest percentage of 80%, 82.57% and 91.77% for C. abyssinica, M. obscura and ascorbic acid respectively. Ascorbic acid demonstrated the lowest value of IC50 of 0.044 and 0.087, 0.065 for C. Abyssinica and M. Obscura respectively. They also demonstrated reducing power that increased with increase in concentration. Different levels of hydrogen peroxide scavenging activity were also demonstrated by the extracts depending on the concentration. There were significant differences between the extracts and the standard. The DCM: MeOH extracts of C. abyssinica and M. obscura demonstrated significant antioxidant activity. The DCM: MeOH extracts of C. abyssinica and M. obscura can therefore be an alternative source of antioxidants for management of different problems that rise due to oxidative stress. The present study, therefore, scientifically validates and supports the traditional use of C. abysssinica and M. obscura in the management of oxidative stress.