Faculty of Science

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Differential Transcript and Protein Expression Profiles in Anopheles Gambiae Sensu Stricto Mosquito Larvae Exposed to Cadmium Heavy Metal
(Egerton University, 2021-11) Ngambi, Catherine Nyawira
Optimization of Extrusion Cooking for a Protein and dietary fibre rich Instant Flour from a Composite Blend of ...
(Egerton university, 2021-07) Wanjala, Nobert Wafula
Analysis of Extruded Ready-To-Eat Baby Foods Prepared Using Composite Flours from Orange-Fleshed Sweet Potatoes, Soybeans, and Amaranth Seeds
(Egerton University, 2023-07) Nkesiga, Jackson
There is severe food insecurity for many people who live in sub-Saharan Africa. The situation is worse for children under the age of five years who are undernourished. This is caused mainly by poverty limiting access to quality foods, as well as poor breastfeeding, and complementary feeding practices. Therefore, the purpose of this study was to develop and analyze the physicochemical properties, microbial, sensory properties, and shelf-life of extruded RTE baby foods prepared using composite flours from orange-fleshed sweet potatoes (OFSP), amaranth seeds, and soybeans. Ready-to-eat (RTE) baby foods which are conveniently distributed to the poor could be a way of mitigating this challenge. Additionally, there are advocacies for the utilization of locally available food resources for sustainable food production. Extrusion technology has been used in many parts of the world to process RTE foods. However, as with most food technologies, there are always questions regarding optimum working conditions, nutritional quality and safety, consumer outlook, and shelf stability that need to be addressed. The ingredients were optimized using the extreme vertices method of mixture design using Minitab Software. The optimum value for model verification was 57% OFSP, 24% amaranth seeds, and 19% soybeans flour, to achieve targeted values of crude protein (14%), total minerals (4.7%), and Vitamin A (813.6 Retinol Activity Equivalent μg/100g). The optimum extrusion cooking conditions were established as 90oC die temperature, 35% feed moisture content, and 400 rpm screw speed based on Box-Behnken Experimental Design of Response Surface Methodology under Design Expert Software. A completely randomized design (CRD) in a factorial experimental design was employed using statistical analysis software (SAS) for the production of extruded ready-to-eat baby foods. The results revealed that extrusion cooking and blend proportions significantly (p<0.05) affected the physicochemical properties, microbial, sensory properties, and shelf-life of extrudates. The extrusion cooking significantly (p<0.05) reduced moisture content (59.5%), protein content by 5.56%, anti-nutrient content (65.24 - 97.43%), and vitamin A content (21.33%). On the other hand, there were significant (p<0.05) increases in carbohydrate (12.31%), total minerals (10.44%), dry matter (7.06%) contents, energy value (6.38%) and energy-to-protein ratio (11.28%). Blend proportions and extrusion cooking have significant (p<0.05) positive effects on the protein quality of the extrudates in terms of in vitro protein digestibility and available lysine. The shelf-life of extrudates was found to be about 4 to 6 months. Therefore, the use of extrusion cooking techniques for OFSP, amaranth seeds, and soybeans composite flours has the potential for the production of value-added OFSP food products. These findings can be used to achieve food and nutrition security in developing countries.
Spatiotemporal Variation in Plasmodium Falciparum Transmission in Selected Sites in Western Kenya
(Egerton University, 2023) Oduma, Colins Okinyi
Asymptomatic malaria infections are a threat to elimination of this vector-borne infectious disease. In many endemic regions, malaria transmission is seasonal. However, the impact of seasonality on Plasmodium falciparum (P. falciparum) gametocyte levels in peripheral blood and their transmission to local mosquito vectors are not well understood. Data describing these parasitological indices across regions of varying transmission intensity is scanty. In addition, malaria transmission can vary significantly over small geographic scales, but the drivers of this heterogeneity are not well understood. This study evaluated the impact of seasonality on P. falciparum transmission potential, trends in parasitological indices across areas of differential malaria transmission, and factors that might correlate small scale variation in transmission. Blood samples were collected from individuals living in Homa Bay County (low transmission) and Kisumu County (moderate transmission) in the dry season (n=1116) and rainy season (n=1743). In addition, blood samples were collected from approximately 150 individuals in each of 20 clusters in Busia County (high transmission) in rainy season. Blood samples were screened for P. falciparum parasites using quantitative polymerase reaction (qPCR) and microscopy. In Homa Bay and Kisumu the presence and density of blood gametocytes was measured by reverse transcription PCR (RT-qPCR). Differences in parasite and gametocyte densities across seasons were determined by unpaired t-test. Differences in the prevalence, proportion of submicroscopic and gametocyte positive infections across study sites were determined by χ2 test. A generalized linear mixed effect model was used to determine predictors of infections. Potential mosquito larval habitats and their number within 250 m of a household were determined by ArcMap. In Homa Bay and Kisumu, mean parasite densities did not differ in dry versus rainy season (P=0.562). Gametocyte densities were 3-fold higher in the rainy than dry season (rainy: 3.46 transcripts/uL blood, dry: 1.05 transcripts/uL, P<0.001). Parasite prevalence and densities, and gametocyte prevalence and densities were highest in the high transmission region. In contrast, the proportion of asymptomatic submicroscopic infections was highest in the low transmission region. Proportion of gametocyte positive infections did not differ across transmission intensities. In Busia County, across the 20 clusters, 3-folds and 4-folds variation in parasites prevalence by qPCR and microscopy respectively was observed. Three to 34 larval habitats per cluster, and 0-15 habitats within a 250m radius around households were observed. Low altitude, kitchen located indoors, open eaves, a lower level of education of the household head, younger age, and being male were significant predictors of higher prevalence. The number of habitats and their proximity to households was not a predictor for prevalence. In conclusion, parasites increase their investment in transmission in the rainy season, reflected by higher gametocyte densities. Seasonal changes of gametocytemia among infections need to be considered when designing malaria control measures. Pronounced variation in prevalence at small scales and the determinants need to be considered for malaria surveillance and control.
The effect of Pesticide Pollutants on Transmission of Schistosomiasis in Western Kenya
(Egerton University, 2023-08) Aziz, Ganatra Akbar Abdul
Schistosomiasis is caused by trematodes that utilise planorbid snails as their intermediate hosts in Africa. The study aimed to determine the effect of pesticides on the transmission of the disease. This was done by first investigating the effect of two commonly used pesticides, imidacloprid, a neonicotinoid, and diazinon, an organophosphate, on the host snails, Biomphalaria and Bulinus, to determine their tolerance. The tolerance of the snail’s competitors and predators was also investigated. Using laboratory experiments, sensitivity distribution graphs were used to determine that the host snails were the most tolerant taxa to the pesticides chosen. Data from the field showed that the snails were present in moderately polluted sites or greater, with a distinct lack of presence in pristine waters. Binomial and mixed effects general linear models were used to determine a minimum effects model of variables that show the distribution of host snails, and were put into a principal component analysis which showed an antagonistic relationship between pesticide pollution and competitors of host snails. This led the study to conclude that pesticide pollution in the field increases the abundance of host snails by reducing the number of competitors, due to the competitor’s higher sensitivity to the pesticides. The effect of pesticides on the parasite itself were then investigated by studying the effects of the same two pesticides on the free-living life-stages of Schistosoma mansoni. The dose-response calculations revealed the tolerance to be 50-60 times the concentration of what was found in the field. Miracidia were further exposed to sub-lethal doses at 20% the EC50s, where it was shown that these concentrations could reduce the proportion of infected snails. However, these concentrations were 500-600 times greater than those in the field. Therefore, the study here shows that pesticide pollution has the potential to increase snail hosts dominance over their competitors in polluted environments, while not affecting the parasite at environmentally relevant concentrations, leading to an overall increase in risk of disease transmission. As pesticide pollution could increase the risk of schistosomiasis, it must be monitored within habitats to determine the change in risk across seasons. The study evaluated the potential of the SPEARpesticide bioindicator for use in Kenya and found it to be promising. Thus, the government of Kenya could potentially use the bioindicator to cheaply and quickly assess pesticide pollution in the rivers of Kenya and use the information to map out potential areas where the risk of schistosomiasis could increase in the coming years.
Evaluation of anti-diabetic effects of phytochemicals from urtica dioica (stinging nettle),salvia officinali(sage),Psidium(Guava) and citrus limon(lemon) using an experimental mice model
(Egerton University, 2020-08) Kanana, Faith Mbiti
Diabetes mellitus affects millions of people Worldwide. In developing countries, diabetes mellitus causes signiﬁcant morbidity and mortality to both children and adults. Although extensive research has been conducted on diabetes mellitus, effective treatment has not yet been reported. Oral anti-diabetic drugs and insulin used in clinical management are expensive, unavailable or have side effects. Therefore, there is need for safer and effective bio-active drugs from medicinal plants. The aim of this study was thus to investigate the anti- diabetic efficacy of phytochemicals from Urtica dioica, Salvia oﬂicinalis, Psidium guajava and Cirrus limon leaf extracts. Three months old fresh leaves of the plants were collected from Egeﬂon University’s Botanical Garden for extraction of phytochemicals. Methanol Was used as the primary solvent for extraction. The resultant plants extracts were partitioned with Water, ethyl acetate and hexane and concentrated using a rotary vacuum evaporator to obtain ethyl acetate, hexane, and aqueous crude extracts. Diabetes was induced in the experimental mice using a single intraperitoneal injection of alloxan monohydrate at a dose of 200 mg/kg body Weight. The crude extracts Were subjected to preliminary in vivo bio-assays for 7 days Where they Were administered orally to experimental mice. Ethyl acetate extract of S. oﬂicinalis and methanol extract of C. limon did not reveal any anti-diabetic effect while the aqueous extract of S. Qﬂicinalis showed signiﬁcant hypoglycemic effect, p< 0.05 compared to other extracts. It Was, therefore, subjected to further hypoglycemic studies Where fasting blood sugar and live Weights of various groups were monitored at intervals of 72 hours for 15 days. There was a signiﬁcant drop in blood sugar levels of the groups treated With S. ojﬁcinalis aqueous extract at 400 mg/kg and 600 mg/kg dosage levels from 452.00 zk 11.13 Mg/dl and 431.00 :1: 10.65 Mg/dl to 256.33 :1: 5.12 Mg/dl and 256.67 :1: 8.74 Mg/dl and Weight gain improvement from 28.05 i 0.39 g and 27.38 i 0.52 g to 29.32 i 0.42 g and 28.55 zt 0.38g respectively compared to controls, p< 0.05. Histopathological analysis of liver and kidney tissues obtained from euthanized mice did not reveal any significant changes compared to the controls. This indicated that the extracts did not confer adverse effects on these tissues. Phytochemical tests of the extracts revealed presence of flavonoids, sterols, saponins, tannins, alkaloids, and triterpenes. Flavonoids and triterpenes particularly have been documented to possess anti-diabetic effects on alloxan induced mice. Results from this study indicate that U. dioica, S. ojjﬁcinalis, C. limon and P. guajava extracts are potential anti-hyperglycemic and can be used in modulating blood glucose with exception of ethyl acetate extract of S. oﬂicinalis and methanol extract of C. limon.
Antibacterial Activity of Chrysanthemum Cinerariaefolium (Pyrethrum) Secondary Metabolites and Green Synthesized Silver Nanoparticles
(Egerton University, 2022-08) Kosgei, Caroline Jepchirchir
The development of resistance to antibacterial agents by bacteria, drive efforts in bio prospecting for new novel compounds that can be used to target these resistant microorganisms. Plants are among natural sources of novel compounds with medicinal importance due to their desirable potency. Besides, plant phytochemicals can reduce metal ions to metal nanoparticles hence play important role in the green synthesis of nanoparticles. In the current study, bioactive compounds against selected bacteria were isolated from pyrethrum plant Chrysanthemum cinerariaefolium by carrying out bioassay-guided fractionation. The isolated compounds were characterized using 1D and 2D Nuclear Magnetic Resonance (NMR). Extracts of organic solvents and aqueous of C. cinerariaefolium were also used in the green synthesis of silver nanoparticles (Ag NPs) via reduction of silver ions present in silver nitrate. Synthesis involved mixing a fixed ratio of plant crude extracts with silver ions and storing the mixture in the dark. Observation of a color change to brown signified the formation of the nanoparticles. The nanoparticles were characterized using UV-Vis, Scanning Electron Microscopy, Transmission Electron Microscopy, EDX (energy dispersive X-ray analysis), and Fourier-Transform Infrared Spectroscopy (FTIR). The compounds isolated were (Z)-2 methyl-4-oxo-3-(pent-2-en-1-yl)cyclopent-2-en-1-yl2,2-dimethyl-3-(2-methylprop-1-en-1-yl) cyclopropane-1-carboxylate (jasmolin I), 2-methyl-4-oxo-3(Z)-penta-2,4-diene-1-yl)cyclopent-2-en-1-yl3-(E)-3-methoxy-2-methyl-3-oxoprop-1-en-yl-2,2-dimethylcyclopropane-1-carboxylate (pyrethrin II), and (Z)-2-(but-2-en-1-yl)-4-hydroxy-3-methylcyclopent-2-en-1-one (cinerolone). The compounds showed more activity on the bacteria as a mixture in the ratio of 1:1:1 than individual compounds, with MIC of 25 mg/ml against Pseudomonas aeruginosa. The compounds can therefore be used as lead compounds in drug discovery against bacteria. All the nanoparticles formed were generally spherical in shape. The smallest and largest nanoparticles had sizes of 22.8± 17.5 nm and 75.3± 19.7 nm and they belonged to dichloromethane-Ag NPs and ethyl acetate-Ag NPs respectively. The particles exhibited size-dependent activity on the selected bacteria. Safety studies on the nanoparticles and pyrethrum extracts on Vero cells showed that they were not cytotoxic hence safe for utilization in drug discovery. Pyrethrum plant therefore possesses phytochemicals that can be used in green synthesis nanoparticles. Other plants should be exploited to ascertain their ability to synthesis nanoparticles.
Effects of Structured Nutrition Education on Maternal Breastfeeding Self-Efficacy, Perceptions and Exclusive Breastfeeding Duration in Kiandutu, Thika-Kenya
(Egerton University, 2017-11) Mituki, Dorothy M.
Despite the fact that the overall benefits of exclusive breastfeeding (EBF) for the first half of infancy have well been established, especially for mother-infant pairs in low social economic status, the rates are low in Kenya. The study aimed at evaluating the effects of structured nutrition education on maternal breastfeeding self-efficacy, perceptions and EBF duration. A cluster randomized controlled intervention was carried out. The intervention included education sessions with the nutritionist at the health centre, monthly home visits by the community health workers (CHWs) plus the usual care at the Maternal Child Health (MCH) clinic. The intervention utilized the national manual on maternal infant and young child nutrition (MIYCN) and emphasized conditions infants were susceptible to with early complementary feeding, simple messages on the importance of positive attitude and making a decision to EBF, as the best choice for mothers, breastfeeding within the first hour of delivery; dietary diversity and importance of proper attachment. Monthly home visits were made by CHWs postpartum to encourage mothers to EBF and answer mothers‘ questions. Anthropometric and feeding data for the infants was collected at 6, 10, 14 and 24 weeks. Maternal anthropometric measurements (weight and height), and breastfeeding perceptions were collected at recruitment (28 weeks) at 38 weeks and 14 weeks postpartum while the feeding data was collected monthly. The primary outcome, duration of EBF for mothers in the intervention (n=256) compared to those in the comparison group (n=176) was examined. Secondary outcomes of the study (breastfeeding self-efficacy, and perceptions) were analysed in relation to involvement in the structured nutrition educational intervention or not. Analysis was done on intention to treat basis. A statistical significance difference was found between the two groups in regarding to EBF duration at 24 weeks log rank= 20.277, (1, n=314) p < 0.001. Intervention group (45.3%) compared to the comparison group (15.0%). The end line (p=0.001) maternal breastfeeding self-efficacy positively predicted EBF duration. Out of the four perceptions, only perceptions on barriers to EBF at end-line (p<0.05) positively predicted the outcome variable. Bivariate analysis yielded two socio-economic significant predictive variables of EBF duration, education level of mothers; (OR 4.75, 95% Cl 1.58-14.30, p=0.006) and household food security (OR 0.03, 95% Cl 0.01-0.09 p=0.001). Being in the intervention group, increased the likelihood of having higher BSE (Log odds 1.41, 95% Cl 0.08-2.75) and EBF duration (Log odds 10.32, 95% Cl 4.26-16.39) Structured nutrition education should be implemented to ensure mothers gain confidence and are able to deal with barriers associated with EBF for the first six months.
Biochemical Changes and Microbial Profiles Affecting Quality and Vase Life of Cut Gladioli (Gladiolus Grandiflorus L. ‘Fado’) Following Pulsing and Cold Wet Storage
(Egerton University, 2021-04) Chore, Judith Kavulani
Floriculture in Kenya remains among the top three foreign exchange earners. Gladiolus is one of the famous cut flowers in the world. Annual losses amounting to 30,000 metric tonnes valued at USD; 166.6 is incurred by farmers due to postharvest challenges. The aimof this study was to determine the vase life and quality parameters of cut Gladiolus grandiflorus L. cv.‘Fado’ as affected by pulsing with 600 ppm 8-hydroxyquinoline sulphate plus 5% sucrose prior to wet cold storage duration(0 – 5 days). The Gladiolus were grown in the open field from corms at the Horticulture Research and Teaching Field, in the department of Crops, Horticulture and Soils, Egerton University, Kenya, during the season of September to December 2014. A two by six factorial experiment embedded in a Completely Randomized Design with four replicates was adopted using Proc GLM model in two way ANOVA. Differences in means were determined using Tukey’s test at 5% level of significance. Pulsing treatments and interactive wet cold storage durations significantly affected cut Gladiolus quality parameters including fresh weight (P< 0.0031; 11.67% increase).,dry weight (P˂ 0.0272 ;17.62% increase)., mean water uptake (P < 0.0001; 38.14% increase)., opened florets (P˂ 0.00095; 59.8% increase) and number of unopened buds (P <0.0256 ; 61-28.88% reduction). The pulsing and cold storage treatments and their interaction significantly (P˂ 0.0001., P˂0.0003.,P˂0.0001 respectively) affected the vase life of the cut Gladiolus (11.5 ± 0.0.148 days versus 4.75 ± 0.148 days; 142% increase).The pulsing treatment coupled with wet cold storage and their interactive effects significantly (P < 0.0001) affected the concentrations of the senescence biomarkers: Total Free Amino Acids, (P<.0001; 21.97% reduction)), Total Soluble Sugars (P < 0.0001; 101.16% increase) and Total Starch(P <0.0001; 309.39 % increased) on the third day in the vase compared with the control. The levels of Total Phenols, anthocyanins and microbial proliferation were also significantly affected (P< 0.0003 (104.14% increase)., P ˂ 0.0012 (26.98% increase)., P < 0.0001 (6.032% reduction) respectively) on the third day in the vase in pulsed spikes wet cold stored for 3 days.Gladiolus cut flowers can be wet stored at 3 ± 1°C up to a maximum of 4 days without any adverse effect on their subsequent vase life and quality. Small scale farmers can adopt pulsing cutG. grandiflorus cv.Fadowith subsequent storage of upto 4 days at 3 ±1 OC to manage bulking and transportation of their produce to reduce postharvest losses. This may increase domestic livelihood withenhanced foreign exchange and consequently food and job security in Kenya.Knowledge from this study will augment existing technologies in improving quality and market value of Gladiolus cut flower.
Molecular products, thermal emissions, and radical kinetics from the thermal degradation of croton megalocarpus biodiesel and binary transport fuels
(Egerton University, 2020-06) Chelangat, Mosonik Bornes
There is an urgent interest initiated to develop clean energy resources with the aim of reducing exposure to environmental pollutants and explore model fuels that can hasten the achievement of clean energy combustion. In order to optimize the pyrolysis of binary transport fuels, diesel blends of ratios 1:1, 3:2 and 2:3 were each pyrolyzed at a contact time of 5 seconds in a quartz reactor at 1 atmosphere pressure, at a model temperature of 500 ºC. The surface morphology of the particulate emission was imaged using a field emission gun scanning electron microscope (FEG SEM) while free radical characteristics such as radical intensities and radical kinetics was investigated using an X-band electron paramagnetic resonance spectrometer (EPR). Surface bound functional groups on thermal char were studied using Fourier Transform infra-red spectrometer (FTIR). Optimized molecular structures were performed using the quantum level of theory incorporated in Gaussian ‗16 and CHEMISSIAN computational codes. The charcoal content for pure fossil diesel was compared with the binary diesel residue. Gas-phase molecular components were determined using Gas chromatography (GC) coupled to a mass selective detector (MSD). Elemental composition of thermal char was determined using Smart Elemental Analyzer. It was noted that at a ratio of 2:3 (Biodiesel: Fossil diesel), harmful molecular products reduced significantly, 76 – 99%. Elemental analysis data indicated that the carbon content from commercial diesel was very high (≈ 70.61%) as compared to approximately 53% for biodiesel-fossil diesel mixture in the same ratio 2:3. Interestingly, the free radical content was reduced by nearly 50% in favour of the biodiesel/fossil diesel mixture. Electron paramagnetic resonance (EPR) results gave a g-value of 2.0024 and a narrow ΔHp-p of 3.65 G. The radical concentration for the first EPR experiment was 9.12 × 1019 spins/g and 4.19 × 1017 spins/cm. The decay rate constant for the radicals was low ( while the half-life was ≈ 431 days. Fourier transform infrared (FTIR) results showed the presence of aromatic hydrocarbons, methyl and methylene groups on the surface of biochar while scanning electron microscopy (SEM) images indicated the existence a polymeric structure believed to be highly carbonaceous. The low g-values and low decay rate constant suggest that the free radicals in the biochar are carbon-based and stabilized by a strong π-π conjugated system. This study reports that a binary biodiesel – fossil diesel ratio of 2:3 is a future promising transport fuel because of reduced molecular emissions and decreased free radicals in
Antiplasmodial and toxicity activities and characterization of chemical compounds extracted from selected medicinal plants in Uganda
(Egerton University, 2018-11) Kodi, Philip
Malaria caused by Plasmodium parasite is at the moment the one of the highest killer disease in the tropics. In developing countries, where malaria is one of the most prevalent diseases, some people still rely on traditional medicine for the treatment of this disease. In the present study an ethnobotanical survey was conducted to document antimalarial medicinal plants. In vitro antiplasmodial and in vivo toxicity activities were carried out on crude root extracts and on the isolated pure compounds from Oncoba spinosa, Acacia sieberiana and Euclea latideus. Structure elucidation was also carried out on the isolated pure compounds. The ethnobotanical survey was conducted by use of semi-structured interviews and a guided questionnaire. The characterization of the isolated compounds was determined using NMR technique only. The antiplasmodial activity was performed using a fluorescence based SYBR Green 1 assay technique on 3D7 and Dd2 Plasmodium strains. Lorke’s method was used to determine the in vivo acute toxicity of the extracts on mice. Thirty three plant species from 30 genera belonging to 23 families were documented, of these ten species (30.3 %) were recorded for the first time as antimalarial plants. Acute toxicity studies showed that all crude extracts of E. latideus and A. sieberiana had LD50 > 5000 mg/kg. The LD50 for hexane and CH2Cl2 extracts of O. spinosa were > 5000 mg/kg while the EtOAc and MeOH had 547.72 mg/kg. The EtOAc extract of O. spinosa had high activity of (IC50) 3D7: 4.69 ± 0.01 μg/mL and Dd2: 3.52 ± 0.02 μg/mL. Extracts of E. latideus had high activity (IC50) 3D7: (9.75-38.21) μg/mL and Dd2: (2.78-38.93) μg/mL. A. sieberiana extracts had the highest activity of (IC50) 3D7: (4.45-27.32) μg/mL and Dd2: (3.38-21.87) μg/mL. Isolation resulted in the identification of eight known compounds which included; three triterpenoids Lupeol, betulin, 3β-(5-methoxyferuloyl)lup-20(30)-ene; two steroids β-sitosterol, stigmasitosterol; benzoic acid and an aliphatic acid chaulmoogric acid. Betulin and β-sitosterol had the highest activity (IC50) 3D7: 3.71 and 5.51 μM, respectively. Antiplasmodial activities of the extracts (IC50: 2.76- > 50) μg/mL, pure compounds (IC50: 3.71- > 120.77) μM of the three plants and the controls (IC50: 0.0056-0.0440) μg/mL showed significance among themselves at (P < 0.05). Extracts and compounds exerted a significant (P < 0.05) decrease in antiplasmodial activity compared to the standard controls. The findings show that the crude extracts and pure compounds have got high antiplasmodial activity and lack toxicity. Therefore the local communities can continue to use the three plants for the treatment of malaria and this justifies the ethanomedicinal use of the plants for the management of malaria.
Antimicrobial activity and phytochemical studies of turraea abyssinica, meyna tetraphylla and leonotis mollissima
(Egerton University, 2019-11) Kinuthia, Esther Wanjiru
Due to the high bills involved in the importation of modern medicinal drugs, about 80% of the African population use traditional medicine from plants to treat common infectious diseases caused by microorganisms. The main objective of this research was to determine the antimicrobial activity of crude extracts and isolated compounds from Turraea abyssinica, Meyna tetraphylla (Abyssinian coral tree) and Leonotis mollissima (Lion’s ear) from Meliaceae, Rubiaceae and Lamiaceae families respectively. They were studied in this research due to their wide use by local communities of Kenya for medicinal remedies. Plant materials were sampled from Kirinyaga East, Narok North, Baringo South, Tharaka Nthi Maua, Laikipia University and Mau Narok in Kenya. They were identified and voucher specimen kept for reference. All the plants crude extracts showed significant antimicrobial activity on all the test microorganism (Bacillus cereus, Staphylococcus aureus, Escherichia coli,Salmonella typhimurium and Candida albicans) at a concentration of 1 mg/ml despite been sampled from different regions of Kenya. They had lower MIC (Minimum Inhibition Concentration) as compared to the Amoxil® and Doxycycline® antibiotics that were used as positive control for comparison. From Turraea abyssinica stem bark dichloromethane crude extract (52.42 g), three compounds 176 (Sitosterol, 4.60 mg), 177 (Scopoletin, 6.00 mg) and 178 [2-(1’,2’ Dihydroxypropyl)tetradecanoic acid, 5.65 mg] were isolated. Of the three compounds only compound 176 showed significant activity on Bacillus cereus, Staphylococcus aureus, and Candida albicans) at a concentration of 2.5 mg/mL to 4.0 mg/mL. Meyna tetraphylla leaves dichloromethane crude extract (45.24 g) gave compounds 179 (Phaeophytin, 9.40 mg), 180 (Enantiomer, 5.80 mg), 118 (α-Amyrin, 5.65 mg) and 60 (Sitigmasterol, 5.82 mg). The Structures of the compounds were elucidated using 1D-and 2D NMR. Experiments. Compound (179) showed significant activity on Escherichia coli and Salmonella typhimurium at a concentration of 4.0 mg/mL while α-Amyrin (118) had significant activity on Salmonella typhimurium at a concentration of 4.0 mg/mL. Leonotis mollissima leaves dichloromethane crude extract (79.69 g) yielded compounds 181 (Sederin, 7.70 mg), 182 (20-hydroxylucidenic acid D2, 7.10 mg) and 183 [(13R)-19α,13α-epoxylabda 6β(19).16(15)-dioldilactone, 21.20 mg]. Only compound (182) showed significant antimicrobial activity on Escherichia coli at a concentration of 0.4 mg/mL. This was a confirmation that the three plants contain compounds that can be isolated and used as drugs to treat various diseases including microbial infectious diseases.
Screening and characterization of some anticancer compounds from Salicaceae, Myrtaceae, Euphorbiaceae and Solanaceae families
(Egerton University, 2019-10) Kipngeno, Chirchir Denis
The chemistry of natural products is very important since it has been used in the search for bioactive compounds for management of various human diseases including cancer. The increase in the incidence of cancer coupled with the undesirable side effects observed with chemotherapic agents urges the discovery of new agents from natural sources. In this study the four ethnomedicinal plants; Dovyalis abyssinica (Salicaceae), Solanum mauense (Solanaceae), Syzigium guinense (Myrtaceae) and Croton dichogamous (Euphorbiaceae) were investigated for their unvalidated anticancer activities. Crude extracts for stem bark of S. guinense, fruits of S. mauense, and roots of both D. abbysinica and roots of C. dichogamous were prepared via cold extraction method. The crude extracts were purified by repeated column chromatography and Thin Layer Chromatography. This resulted in various pure compounds which were analysed by use of 1D NMR, 2D NMR spectroscopic techniques and MS spectrometry. The NMR spectral data obtained together with MS data were interpreted, the structures of the compounds elucidated and their chemical structures proposed. A total of twelve compounds were isolated, purified, their chemical structures proposed and four of these compounds were evaluated for their anticancer activity. Two previously reported compounds; β-sitosterol (47) and betulinic acid (21), were obtained from stem bark extracts of S. guinense as well as from the fruits extracts of S. mauense. Two previously reported compounds; Tremulacin (29) and Benzoic acid (48) were isolated from the roots extract of D. abyssinica. Eight compounds were isolated from roots extract of C. dichogamous; Acetyl aleuritolic acid (49), 3β,4β:15,16-diepoxy-13(16),14-ent-clerodadiene (50), 3β, 4β:15, 16-diepoxy-13(16), 14-ent-clerodadien-17,12S-olide (51), 15,16-epoxy-5, 13(16), 14-ent-halimatriene-3-ol (52), crotodichogamoin A (53), crotohaumanoxide (54), crotodichogamoin B (55) and Cadin-1(6),2,4,7,9-penta-ene (56). Selected compounds were evaluated for their anticancer activity by use of cancer cell lines. Betulinic acid (21) was screened against 57 cell lines and only 25 gave positive results. Acetyl aleuritolic acid (49), 15,16-epoxy-5,13(16),14-ent-halimatriene- 3-ol (52) and crotodichogamoin A (53) were also evaluated for their anticancer activity and and their one dose mean value percentage growth at 15 μg/ml were 97.86, 99.39 and 100.6, respectively. The mean values of growth inhibition of the three compounds tested against one dose NCI cell line panel did not meet the standards for further testing against the five-dose NCI cell line panel. The study recommends toxicological studies be done on the medicinal plants extracts to enhance their full exploitation.
Chemical characterisation and antimicrobial activity of Compounds from some selected medicinal Kenyan ganoderma and trametes species
(Egerton University, 2020-06) Mayaka, Regina Kemunto
They are a unique group of fungi usually ignored by most fungi enthusiasts because of their typical inedibility, unfamiliar habitat and general opacity. In addition to their traditional use, contemporary research has suggested many applications for cancer treatment and boosting of the immune system. Due to increase in bacterial resistance to existing antibiotics infectious diseases have remained a major threat to human health. Hence bioactive compounds are continuously sought for disease prophylaxis and treatment. The main objective of the current work was to evaluate bioactive compounds from medicinal polypore species Ganoderma adspersum, Ganoderma applanatum, Ganoderma australe and Trametes elegans collected from Mau, Kericho area, Kabarnet and Kerio valley forests in Kenya. The dried, ground fruiting bodies of the species were extracted with methanol to give methanol crude extract, then consecutively extracted using ethyl acetate solvent to obtain an ethyl acetate extract. Fractionation and purification using column chromatography technique and further purification of some compounds was achieved on sephadex LH20. The chemical structures were determined on the basis of NMR spectroscopic data from 1H and 13C NMR, HSQC, HMBC, 1H-1H COSY and NOESY experiments, and by comparing obtained results to the values indicated in previous studies. The polypore Ganoderma adspersum yielded ergostane compounds namely ergosta-7,22-dien-3-one (54), ergosta-7,22-diene-3β -ol (55) and ergosta- 5,7,22-trien-3-ol (56). Ganoderma applanatum gave five compounds, 55, 56, 5α,8α– epidioxyergosta-6,9(11),22-trien-3β-ol (57), 5α,8α–epidioxyergosta-6,22-dien-3β-ol (58), 24- hydroxy-olean-12-en-3-one (59). The fruiting body of Ganoderma australe yielded compounds 55, 56 and 57 and Trametes elegans gave 55, 56, ergosta-7,22-dien-3,5,6-triol (60), lupeol (61) and 9,19-cycloartane-3,30-diol (62). Antimicrobial activity was assessed against important clinical bacterial and fungal strains and zones of inhibition examined using one-way ANOVA through Tukey’s PostHoc test. Most notable inhibition being against Streptococcus pyogenes 9.7 0.58 mm by compound 56, 9.0 0.58 mm by compound 55, 9.0 0.58 mm by a mixture of 57 and 58 and 8.0 0.33 mm by compound 59. It was observed that all Gram negative bacteria were insensitive to the treatment of compounds. In conclusion the study has indicated that the isolated compounds have antibacterial properties hence have demonstrated their potential as antibacterial agents. The research has also revealed that our natural indigenous forests still harbours novel natural bioactive substances and strains that needs to be investigated for novel myco-medicines in the future.
Physico-chemical qualities of selected potato (solanum tuberosum l.) cultivars and their suitability for product diversification in Rwanda
(Egerton University, 2019-11) Ndungutse, Vedaste
Potato (Solanum tuberosum L.) is bulky and perishable with up to 50% of losses in 3-5 months of storage. Losses can be reduced through processing into less bulky and more stable products. The aim of this study was to investigate morphological and biochemical factors which affect potato quality, effect of potato cultivars and fermentation on quality of French fries and crisps as well as starch characteristics. Cultivars used included vartieties like Gikungu, Kigega, Kinigi, Kirundo, Mabondo, and Sangema and clones such as CIP399075.22, CIP392617.54, CIP 393251.64 and CIP399062.115. Laboratory experiment was Completely Randomised Design (CRD) with three replications. The skin colours were red, white, yellow, pink or purple, while the flesh was yellow or white. Specific gravity was 1.075-1.099, dry matter (DM) 20.45-25.93%, starch 14.33-19.28% on Fresh Weight Basis (FWB). Reducing sugars were 0.10-0.20%, non-reducing sugars 0.16-0.35%, and total sugars 0.26-0.55% FWB. Kinigi, Kirundo, Mabondo, Sangema and CIP393251.64 were selected for processing suing discriminant analysis. Discriminant analysis did not distinguish these cultivars for crisps and French fries. Internal oil was higher than surface oil and lower for French fries than crisps. Total oil was 11.97-18.48% for French fries and 33.49-42.84% for crisps. Fermentation increased acidity 0.01-0.02%, reduced pH 7.30-4.31, acrylamide 629.6-267.73 μg/kg for French fries and 855.30-339.59 μg/kg for crisps. Potato flour had high water absorption capacity (WAC) 265.39-303.11%, oil absorption capacity (OAC) 99.21-123.14%, foaming capacity (FC) 6.27-18.05% and emulsification capacity (EC) 30.00-44.17%. Rapidly digestible starch was 0.82-2.00% for raw potatoes, 46.71-50.87% for French fries, 69.66-70.31% for crisps; slowly digestible starch was 5.89-14.40% for raw potatoes, 37.35-38.58% for French fries, and 23.50-27.21% for crisps; resistant starch was 83.61-93.30% for raw potatoes, 10.25-14.53% for French fries, 2.91-8.20% for crisps; glycemic index (GI) was 59.44-68.37% for French fries, 66.23-70.23% for crisps; glycemic load (GL) was 9.91-13.36% for French fries and 11.05-13.57% for crisps. High DM and low reducing sugars are indicators of good quality potato for fried and dehydtared products. Oil absorption reduced with increase of DM. Reduction of acrylamide increases safety of the products. High WAC of flour is an indicator for use in food as thickening agent and where bulk is needed and high OAC is good for flavour retention which inceases food palatability. GI and GL were medium for both as a crisps and French fries and they can be used for control of metabolic disorders. Therefore, potato in this study can be used
Haematological and tissue enzyme changes in a sheep model infected with Trypanosoma brucei rhodesiense
(Egerton University, 2017-11) Mavura, Hawa
Control and management of human African trypanosomosis faces many challenges including limited available drugs that are stage specific and also toxic, treatment failures and post treatment CNS and cardiac pathology which might be fatal. Because of ethical considerations, trypanosomosis and drug trial studies are conducted using animal models which have drawbacks. It is therefore important to develop models that can address the current drawbacks and also develop enzymatic disease staging markers to detect CNS and cardiac involvement in order to institute correct choice of trypanosome drugs and/or use of adjunct to mitigated conditions. The current study evaluated a sheep model infected with Trypanosoma brucei rhodesiense as a cheap and reliable model of human trypanosomosis. In addition the model was used to asses clinical signs, haematological changes and the use of total and isoenzyme CK and LDH levels in serum and CSF as markers of cardiac and staging of CNS infection, respectively. Eight sheep were infected with 1 × 10 4 T.b rhodesiense and two were uninfected controls. Blood was collected from the ear and jugular vein for parasitemia and for haematological and biochemical changes, respectively. CSF was also collected for cells and biochemical changes while total CK and LDH plus their respective isoenzymes were done by using starch gel electrophoresis and their quantification by a UN-SCAN IT densitometry. Infected sheep developed acute infection accompanied by clinical signs and haematological changes that mimicked infections in humans, including loss of body weight and fever.The infection was also characterized by an increase in MCH and MCHC. However, there was a decline in the levels of PCV, HCT, Hb, MCV and RBC counts. All parameters however recovered to control levels after treatment.This study also showed an increase in total protein, total LDH and total CK activities in both serum and CSF of infected compared to uninfected sheep. At the same time LDH and CK total enzyme and isoenzyme changes indicated cardiac involvement suggesting the diagnostic potential of the enzymes. However the infection did not develop a chronic CNS infection since following humane treatment of the infected sheep with berenil this resulted in cure of the infection and thus did not lead to late stage CNS infection. The study indicated that the T. b.rhodesiense sheep model can be a useful animal model of human African trypanosomosis. However, the study needs to be repeated using a less virulent or low dose of trypanosome to ensure the disease develops to the chronic stage.
Effects of some abiotic and biotic factors on the zooplankton community in Lake Baringo, Kenya
(Egerton University, 2014-10) Omondi, Reuben
Lake Baringo is a turbid lake that lies in a closed drainage basin of the Kenyan East African Rift Valley. The lake’s water quality has deteriorated in the recent past mainly due to sedimentation from its catchment arising from poor agricultural practices, deforestion and overgrazing. Its fishery has also declined since the 1980s and frequent lake closures to fishing activities have not alleviated the problem. This shows that there may be other critical ecological and environmental factors affecting the ecosystem. To understand problems facing the lake, there is need for well-coordinated and comprehensive ecological investigations considering the complexity of the ecosystem. Zooplankton is important in energy transfer from primary producers and constitute a significant component of the diets of the juveniles and some adults of many fish species. The objective of the present study was to determine the effect of some physical, chemical and biological factors on the spatial and temporal distribution, abundance and biomass of zooplankton in Lake Baringo. Stratified random design was used to allow for statistical comparison between zooplankton abundance and biomass at different stations and months with environmental factors using Analysis of Variance (ANOVA). The relatively stable environmental factors across the sampling stations in the lake were attributed to its small size, shallowness and the daily mixing by wind action. A total of 39 species of zooplankton belonging to Rotifera, Cladocera and Copepoda groups were recorded. The results indicate that distribution, diversity, abundance and biomass of zooplankton were influenced by environmental factors especially depth, conductivity and turbidity. Diel vertical distribution of zooplankton was the reverse of what is reported from clear lakes with organisms congregating to the surface during the day and descending to the bottom at night. Investigations into the diet of three main fish species in the lake showed that Oreochromis niloticus baringoensis mostly depended on algae, Clarias gariepinus depended on fish while Protopterus aethiopicus thrives on molluscs as their dominant food. The growth performance of the once dominant endemic fish, O. niloticus baringoensis could be affected by the high turbidity, which reduces primary production. Moreover, reduced clarity hampers the feeding success of this visual feeding fish and has decreased macrophytes to near extinction. There is urgent need for rehabilitation of Lake Baringo and the study recommend afforestation and reduction of livestock numbers in the catchment as some of the ways of reducing soil erosion and sediment input in the lake. The results of the study may be used as an important tool for the detection of stability and trophic levels of the ecosystem and to provide data for models on maximal resource production of the lake.
Influence of nutrition and value chain governance on enterprise performance in smallholder pig production in Kenya
(Egerton University, 2019-01) Muthui, Jonah N.
Smallholder pig production in Kenya is a popular livelihood strategy but is faced with serious challenges, key among them being high cost and poor quality of feeds and weak value chain governance which result in high enterprise costs. To minimise losses, smallholders use locally available alternative feed resources (AFR) which coud be impacting negatively on performance. This study investigated feeding decisions, bio-economic benefits of using alternative feed resources (AFR), benefits of exogenous dietary enzymes and the influence of value chain governance features on competitiveness of smallholder pig enterprises. A proportionate to size purposive sampling procedure was used to select 144 enterprises in Busia, Nakuru and Kiambu Counties using the snowballing method. Interviews were conducted using pretested structured questionnaires to collect data on enterprises. Feeding experiments were set up at Egerton University Tatton Agricultural Park. Mixed analytical methods including decriptive and inferential statistics and regression analysis were applied using SAS systems, SPSS and STATA statistical software. The study concluded that the daily allowances of dry matter, crude protein and metabolisable energy associated with AFR were significantly lower (p ≤ 0.05) than the recommended daily allowance. Sows fed on AFR had delayed puberty, lower litter sizes and longer farrowing intervals compared to sows fed on commercially compounded feeds (p ≤ 0.05). Inclusion of cold pressed canola meal and rice polishing in weaned piglet diets resulted in higher (p ≤ 0.05) metabolisable energy: average daily gain (ME: ADG) and feed cost: average daily gain (FC:ADG) ratios. Inclusion of rice bran in piglet diets did not offer any bio-economic benefits. Inclusion of a dietary multi-enzyme complex resulted in higher (p ≤ 0.05) apparent digestibility of Nitrogen, energy and feed cost efficiency. Finisher diets lower in protein (14.9 -16%) and higher in dietary fibre resulted in higher (p ≤ 0.05) killing-out percent, loin eye area and villous height. Cold pressed canola diet resulted in higher (p ≤ 0.05) back fat thickness and larger (p ≤ 0.05) crypt depth. Value chain governance features including technology adoption product quality and market access had significantly (p ≤ 0.05) positive influence on enterprise competitiveness. The quality of work in pig enterprises negatively (p ≤ 0.05) influenced competitiveness of pig enterprises. The study recommend capacity building for farmers and extension staff, animal feed testing and use of biotechnology to improve feeding decisions. Further research into waste conversion technologies, the effects of dietary components such as lipids, phenolics on carcass and digestive tract are recommended.
Analysis of micronutrients and heavy metals of indigenous reed salts and soils from selected areas in Western Kenya
(Egerton University, 2016-11) Tsikhungu, Phanice Wangila
Most communities in Western Kenya use plant indigenous salts for cooking, medicinal and numerous uses. Typha latifolia and Cyperus rotundus reeds are widely used in Busia and Lugari regions of Western Kenya to prepare indigenous salts. The suitability of these salts and validation of micronutrients and heavy metals is unknown. The objective of this study was to assess the suitability of the indigenous reed salt used in selected parts of Western Kenya. Micronutrients and heavy metal concentrations in soil habitats, C. rotundus and T. latifolia and reed salts were determined; In addition, the effect of the various methods of processing, storage conditions and the stability of iron and iodine nutrients has been investigated. Iodometric titration (Iodine), 1, 10-phenanthroline method (Iron II), flame photometric method (Na and K) and Atomic absorption spectrophotometric method (Pb, Cd, Fe, Cr) were used for analysis. Results showed that 85% of Lugari and Busia inhabitants in Western Kenya use C. rotundus and T. latifolia reed salts. Heavy metal in the soil was of the order Fe> Cr >Pb > Cd for the dry season and Cr > Fe > Cd > Pb for the wet season both in top and sub-surface soils with higher levels in the dry season. Salt iodine was of the order Kensalt >Top-chef salt > Herbal sea salt > Sea salt > C. rotundus salt > T. latifolia and Herbal sea salt >C. rotundus salt = T. latifolia salt > Sea salt > Kensalt = Top-chef salt for Fe2+. C. rotundus and T. latifolia reed salts had higher iodine (1.1 mg/kg) than the WHO limit of 0.015 - 1.1 mg/kg , while the concentration of Fe2+ (0.9 mg/kg and 1.0 mg/kg) was below the recommended limit of 8 - 45 mg/kg. The Na: K ratio of T. latifolia salt (3.2:1) was within the recommended limit of 2.5:1 - 4:1 while that of C. rotundus salt (0.9:1) is lower. Fe, Pb and Cd levels in both C. rotundus reed and T. latifolia reed salts exceeded the WHO/FAO permissible. Effectively all iodine and Fe2+ present in the reed salts was lost within six months of storage under normal conditions of temperature and RH with more losses at elevated temperature and relative humidity. T. latifolia salt prepared using complete evaporation method and stored in LDPE container for a period not more than three months is suitable for use as table salt. C. rotundus prepared by complete evaporation method is ideal for use as a low-sodium salt.
Molecular characterization of Trypanosoma brucei brucei and Trypanosoma brucei rhodesiense isolates and responses of Glossina pallidipes to Trypanosoma brucei brucei challenge
(Egerton University, 2016-04) Bateta, Rosemary Wanyona
African trypanosomiases are a group of related diseases that affect humans (Human African Trypanosomiasis - HAT) and their livestock (Animal African Trypanosomiasis), with devastating medical and economic consequences for Africa. The diseases are caused by trypanosome parasites cyclically transmitted by tsetse flies. Recent reports indicate that HAT is on the decline in sub Sahara Africa. However, the disease still remains a major health problem in some parts of Africa such as South Sudan, Democratic Republic of Congo and Uganda. Reports also indicate repeated irregular T. b. rhodesiense out breaks in traditionally endemic areas in south-east Uganda, with continued spread to previously unaffected areas in central Uganda. Although the disease has been reported to spread to new areas in Uganda, observations in the field indicate that the infection rates in tsetse flies are very low. Competence of the flies to transmit the parasite is determined by host midgut responses that either leads to clearance (self-cure) or establishment of the parasite infections. Investigations were conducted to determine evolutionary dynamics behind the origin of new foci and the impact of host species on parasite genetic diversity in Uganda. Trypanosoma brucei isolates {N = 269, n= 58(for Samples isolated from cattle)} were collected from different areas in Uganda and western Kenya and genotyped at 17 genetic marker loci (microsatellite). Analysis was carried out using Bayesian clustering and Discriminant Analysis of Principal Componens. Presence of serum resistance associated (SRA) gene in the isolates was determined using PCR. Results showed that the genotyped trypansosome isolates partitioned into three distinct genetic clusters. Clusters 1 and 3 included isolates from central and southern Uganda, whereas cluster 2 was composed of mainly isolates from western Kenya. FST values between sampling sites ranged from 0 to 0.67 while between the three genetic structures it ranged from0.24 to 0.46 with most values being statistically significant P<0.01. AMOVA results at p<0.05 indicated that the genetic variation was apportioned within (71.8%) rather than among the three clusters. These analyses revealed genetic admixture among the three genetic clusters and long-range dispersal, suggesting recent and possibly on-going gene flow between them and the new foci of HAT in central Uganda is as a result of northward movement of Trypanosoma brucei rhodesiense from the traditionally endemic foci. Therefore disease control efforts need to be enhanced to prevent continued spread to new foci. To determine molecular responses in Glossina pallidipes challenged with trypanosomes, teneral female Glossina pallidipes flies were challenged with Trypanosoma brucei brucei and vii dissected at 24 or 48 hours post challenge (hpc). Tissues were collected and analysed to establish key molecular responses mediating initial phase of establishment of the parasite in the fly. Transcriptomes of midguts and respective carcasses from the challenged and unchallenged flies were sequenced on illumina RNA-Seq platform, and analyzed for differentially expressed transcripts by mapping the RNA-Seq reads on G. pallidipes gene models. The transcripts were annotated and examined for enrichment of gene categories using, heat maps, BLAST2GO and R spider network software. Results from this study indicated that most of the differentially expressed transcripts at 24 hpc were associated with lipid remodeling/lipogenesis, proteolysis, urea cycle, carnitine trafficking, collagen metabolism, apoptosis, and cell growth/differentiation. Transcripts associated with 48 hpc included those linked to embryonic growth and development, muscle/motility, suppression of tumor, serine endopeptidase and related proteosomal degradation of target protein, enhanced translation of mRNA and neuronal development. There was pronounced expression of immune responsive transcripts 48 relative to 24 hpc, indicative of gradual maturity of immune responses in the fly or institution of vector-parasite endemic stability in the guts to facilitate the establishment of infection. Overall there was a systematic suppression of immunity in the G. pallidipes midgut in the initial phase of T. b. brucei challenge, which potentially facilitated initial establishment of the infection. Gradual and sequential immunological responses subsequently emerge contingent with the durations of challenge.

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