RP-Department of Chemistry
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Item Controlling Rate of Release of Tsetse Fly Repellent Blend byEncapsulating in β-Cyclodextrin Nanoparticles(Journal of Nanotechnology, 2025-05) Ratemo, Bernadatte M.; Wachira, Benson M.; Masika, Eric; Ng’ang’a, Margaret M.; Hassanali, Ahmed; Mireji, Paul O.Tsetse flies are major vectors of African trypanosomiasis, with devastating medical and veterinary consequences in sub-Saharan region of Africa. Insect repellents are promising tool for control of tsetse flies in the region. A four-component tsetse-repellent blend (δ-nonalactone, heptanoic acid, 4-methylguaiacol, and geranyl acetone) previously formulated and optimized was encapsulated in β-cyclodextrin for a slow controlled release. Here, we explored various methods of microencapsulating (kneading, coprecipitation, heating, or freeze-drying) tsetse fly repellent blend in β-cyclodextrin nanoparticles. We assessed release kinetics of the blends and individual compounds using gas chromatography linked with flame ionization detector and evaluated laboratory and field responses (repellence) of the flies by the encapsulated blends. We compared individual performances of releases kinetics of the encapsulated blend relative to nonencapsulated composites. Overall, kneading, coprecipitation, heating, and freeze-drying microencapsulation techniques retained 72.0%, 61.0%, 59.5%, and 57.3% of the blend, respectively. Release rates of blends in 400- and 200-microns thick polythene sachets were 6.73 and 11.82 mg/h, respectively, significantly higher (p < 0.05) than that of the kneaded encapsulated blend (5.35 mg/h). Laboratory and field responses of tsetse flies to the unencapsulated native (sachet) and kneaded encapsulated odor blends confirmed our laboratory findings. Microencapsulation technology of repellent odors can be used for controlled release of active molecules in order to give an extended protection period, potentially reducing operational cost in programs for control of tsetse flies and related insect vectors.Item Removal of Nitrites from Wetland Waters Based on Diazonium Silica(SAP, 2025) Kathambi Aquiline; Njoroge Peter W.; Opiyo Sylvia A.; Waweru Isaac; Mwangi Benson M.Diazonuim silica was prepared and used to remove nitrites in wetland waters. Raw silica was chlorinated using phosphorous pentachloride (PCl5). Chlorinated silica was further reacted with ethylenediamine (EDA) under reflux to give aminated silica. Thereafter, aminated silica was protonated to yield diazonium silica which was used as the adsorbent. The prepared diazonium silica material was characterized using Fourier Transform Infrared (FT-IR) showing bands at wavenumbers 1049 and 791 cm-1 of the anti-symmetric and symmetric stretching modes (Si-O-Si) of SiO4. The shift in spectra band of Si-O-Si from 1051cm-1 in raw silica to 1049cm-1 , was attributed to diazonium silica. Additionally, a new open chain azo (N=N) group band was found in the region 1575cm-1 -1630cm-1 . The physical adsorption parameters examined using batch adsorption system including: pH, initial concentration, contact time and temperature were made using sorption models, adsorption kinetics and thermodynamics. The results obtained showed 3.0 as the optimal pH for adsorption of NO2 - , 303K as the optimal temperature, optimum contact time as 60 minutes and optimal initial concentration as 20ppm. The adsorption capacity of nitrites using diazonium silica adsorbent was achieved at 16.45mg/g. For sorption of nitrites in diazonuim silica, Langmuir isotherm model was obeyed according to correlation coefficient R2 = 0.97182 close to unity. Adsorption kinetics of nitrites in diazonium silica pseudo second order was best obeyed while, thermodynamic parameters revealed that the sorption of nitrites into diazonium silica was exothermic in nature. From the results obtained, diazonium silica is an efficient adsorbent for adsorption of nitrites compared to raw silicaItem Levels of Cadmium, Copper, and Lead in Soils and Cassava Tubers Grown in Machakos County, Kenya(Applied and Environmental Soil Science, 2024-08)Item Dietary Mycotoxins: An Overview on Toxicokinetics, Toxicodynamics, Toxicity, Epidemiology, Detection, and Their Mitigation with Special Emphasis on Aflatoxicosis in Humans and Animals(MDPI, 2024-11) Kibugu, James; Munga, Leonard; Mburu, David; Maloba, Fredrick; Auma, Joanna E.; Delia, Grace; Lindahl, Johanna F.Mycotoxins are secondary metabolites of filamentous fungi and ubiquitous dietary contaminants. Aflatoxins, a group of mycotoxins with high prevalence and toxicity, have raised a high level of public health concern, the most prevalent and toxic being aflatoxin B1 (AFB1). Many aspects appertaining to AFB1 poisoning are not well understood. Yet this information is necessary to devise appropriate surveillance and mitigation strategies against human and animal aflatoxicosis. This review provides an in-depth update of work carried out on mycotoxin poisoning, particularly aflatoxicosis in humans and animals, to identify gaps in knowledge. Hypotheses explaining the functional significance of mycotoxins in fungal biology and their dietary epidemiological data are presented and briefly discussed. The toxicology of aflatoxins and the challenges of their mitigation are discussed in depth. It was concluded that the identification of potential mycotoxin-hazard-prone food items and quantification of the associated risk of cancer ailments in humans is a prime priority. There is a dearth of reliable sampling methodologies for estimating AFB1 in animal feed. Data update on AFB1 in animal feed and its implication in animal production, mitigation strategies, and elucidation of risk factors to this hazard is required. To reduce the burden of aflatoxins, surveillance employing predictive technology, and biocontrol strategies seem promising approaches.Item Analysis of Physico-Chemical Parameters and Selected Heavy Metals in Aquatic Ecosystems.(IOSR-JAC, 2023-09) MunenePaul M.; Mbugua, Gerald W.; Wanjau, Ruth N.; Ndiritu, N. JamesThe quality of aquatic ecosystems is of great concern. Elevation of pollutants in water could cause health disorders in human and destabilize the aquatic ecosystem. The case study investigated quality of water from five sites of Lake Turkana selected based on proximity to potential anthropogenic pollution sources. Temperature, pH, electrical conductivity (EC), dissolved oxygen (DO), salinity, total dissolved solids (TDS) and OxidationReduction Potential (ORP) were measured at the site using YSI Pro 1030 Multiparameter electrode while nitrates and phosphates were determined at Kenyatta University’s food science laboratory using Vis 130 Spectrophotometer. Selected heavy metals (lead, cadmium and chromium) were determined using flame atomic absorption spectroscopy. Sampling was performed in triplicates during the dry season. The results were: temperature (28.24±0.96 to 28.86±0.38°C), pH (9.04±0.21 to 9.46±0.06), electrical conductivity (281.57±0.41 to 289.46±3.95 Ωcm-1 ), dissolved oxygen (6.3±0.79 to 7.04±0.05 mg/L), salinity (1.67±0.00 to 1.70±0.01 ppt), TDS (2093.4±0.39 to 2135.8±4.86 mg/L), ORP (-54.22±0.12 to 588.14±0.51 mV), nitrates (5.52±0.31 to 10.04±1.82 mg/L) and phosphates (0.47±0.06 to 0.72±0.15 mg/L). Water lead (0.11±0.01 to 0.12±0.00 mg/L), cadmium (0.00±0.00 to 0.03±0.00 mg/L) and chromium (0.01±0.00 to 0.03±0.01 mg/L). The results showed that pH and TDS were beyond WHO standard of 6.5-8.5 and 600.0 mg/L respectively while phosphates exceeded USEPA limit of 0.024 mg/L in all sites. The electrical conductivity and nitrates complied with WHO standards of 400.0 Ωcm-1 and 50.0 mg/L respectively while the other parameters were not guided by WHO. The lead levels in water exceeded WHO standard of 0.01 mg/L in all sites. The cadmium levels in Impressa and Long’ech beaches in the upstream section exceeded WHO standard of 0.003 mg/L. However, chromium complied with WHO standard of 0.05 mg/L in all sites. These calls for measures keep all the parameters under surveillance to ensure water quality is maintained.Item Bioavailability of Antioxidant Vitamins in Selected Indigeneous Vegetables and their Potential use in Management of HIV/AIDS in Butula, Busia, Kenya(ACRI, 2024-04) Nambafu, Rachel WanjiruThe study investigated feeding pattern of PLWHA in Butula division, determined vitamin A, C and E content and bioavailability in selected indigenous foods for use in the management of HIV and AIDS. Animal and plants foods accounted for 45.17 %, 21.9 %, 17.48 % and 73 % respectively of total foods consumed. Fresh blanched vegetables, contained high levels of β-carotene; 4000- 9700µg/100g and α-tocopherol; 3000-7350µg/100g. Solar dried vegetables contained β-carotene of range 572-854µg/g DW and α-tocopherol of 281-673µg/g DW which is significantly lower (P<0.05) than fresh vegetables determined by HPLC. L-ascorbic acid content in fresh vegetables and fruits determined by redox titration ranged from 6 to 65mg/100g. Mean serum retinol, αtocopherol and β-carotene levels were 0.937, 0.144 and 17.787µmol/l respectively determined using HPLC. CD4+ cell counts in blood determined using flow cytometer were within the normal range of 500-1500 cells/µl while the CD8+ cell count was in the range of 300-3300 cell/µl of blood. Hb was less than 12 g/dL and RDW was less than 15.2% indicating anaemia. 88.35% of the subjects had a CD4/CD8 ratio of less than 1, 9.71% had a CD4/CD8 ratio range of 2-3 and 1.94% had a ratio greater than 4.77.95% of the subjects had a normal weight, 11.81% were underweight, 8.66% were overweight and 1.57% were obese. Bioavailability in foods estimated using algorithm indicated a +2.17 change in serum β-carotene and +7.776 changes in serum α-tocopherol levels indicating that consumption of the foods would result to improving bioavailability of these nutrients in PLWHA in Butula.Item Method Development and Optimization of Liquid Liquid Microextraction Based on the Decomposition of Deep Eutectic Solvent for the Determination of Chromium (VI) in Spinach: Assessment of the Greenness Profle Using Eco scale, AGREE, and AGREEprep(Springer, 2024-01) Moema, D.; Makwakwa, TA.; Nyambaka, H. N.; Dube, S.; Nindi, MMA simple, efective, and ligandless liquid-liquid microextraction (LLME) procedure based on the decomposition of hydrophobic deep eutectic solvents (HDES) was developed for the separation and pre-concentration of chromium (VI) ions in spinach leaves, before the determination by fame atomic absorption spectrophotometry. In the proposed study, the frst stage involved the leaching of chromium (VI) from spinach leaves with 0.1 M Na2CO3, and in the second stage, chromium (VI) extract was preconcentrated with the LLME procedure using a DES prepared from the combination of DL-menthol and formic acid as a chelating agent and extraction solvent. The DES decomposed in an aqueous donor phase resulting in the dispersion of menthol and extraction of Cr (VI) ions. Under optimal experimental conditions, the limits of detection (LOD) and quantifcation (LOQ) were 0.63 and 2.1 µg L−1, respectively. The relative standard deviation (RSD) was less than 7%, and the pre-concentration factor (PF) was found to be 31.25. The accuracy of the present methodology was tested by recovery experiments. The greenness of the developed method was assessed using three quantitative green metrics tools: Analytical Eco-scale, AGREE, and AGREEprep, with only Analytical Eco-scale qualifying the proposed method as green.Item Green Superabsorbent Hydrogel Derived from Activated Charcoal and Glycerol with Maleic Acid as a Cross-Linker(Journal of Experimental Sciences, 2024-02) Kasimu, Titus M.; Mbuvi, Harun M.; Maingi, Francis M.Superabsorbent hydrogels characterize a set of polymeric materials with three-dimensional structures capable of absorbing large amounts of water due to their hydrophilic functional groups on their surface. Their application in industries, agriculture, and the environment is of primary significance. This study reports the synthesis and characterization of green superabsorbent hydrogels derived from activated charcoal. The process involved a polymerization reaction between activated charcoal (AC) with glycerol (G) using sodium hydroxide as an initiator in the absence and presence of maleic acid as a crosslinker to synthesize HCG-1 and HCG-2 superabsorbent hydrogel respectively. Characterization of the hydrogels was done using Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscope (SEM), and X-ray diffraction (XRD). Optimization conditions were done by synthesizing hydrogel with varying dosages of both activated carbon and maleic acid as well as swelling time. The FT-IR results showed the appearance of strong sharp peaks at 1591.34 cm-1 and 1400.28 cm-1 in HCG-1 associated with -COO¯ symmetric stretching and asymmetric bending vibrations, indicating interlink between reacting monomers. Anew absorption band at 1639.48 cm-1 associated with -COO¯ bending in non-conjugated ester indicates ester-crosslink in HCG-2 hydrogel. XRD analysis showed a phase shift from semi-crystalline to crystalline structure upon crosslinking. SEM analysis showed a crystalline intact, rigid structure without voids and pores on its surface in HCG-1 compared to the smooth irregular pores and lamina structure observed in HCG-2 hydrogel. The dosage ratio of AC: G: maleic acid of 8:5:1 produced hydrogel with an optimal water absorption capacity of 1255.80±0.70%. Maleic acid was found to improve the water absorption capacity of the superabsorbent. The study is an eye opener towards the application of biodegradable hydrogels in agriculture, especially in semi and arid regions.Item Effect of Processing Methods on Nutrient and Anti-Nutrient Composition of Grasshopper and Termites(Tylor and Francis, 2023-11) Gachihi, Anne; Tanga, Chrysantus; Nyambaka, Hudson; Kimiywe, JudithDifferent processing methods could impact on the nutritional and anti-nutritional composition of edible insects. This study involved the analysis of nutrients and anti-nutrients in fresh and processed grasshopper (Ruspolia differens) and winged termites (Nasutitermes spp) in Kenya. Proximate analysis was done using AOAC methods, minerals analysis using AAS and anti-nutrients analysis using UVVIS and titration. Moisture content reduced significantly to less than 10% on processing, while ash content increased significantly by more than 50% on processing. Processing did not affect the crude fibre content but it led to a 0.2–90% decrease in crude fat. Processing increased significantly the protein content but did not significantly influence mineral levels; however calcium content was reduced considerably. Anti-nutrient levels decreased significantly on processing by 2%–70% with oxalates and phytates having the highest decrease. These results show that oven-drying and defatting methods retained higher nutrient composition in the edible insects.Item Review of the Effect of Grinding Aids and Admixtures on the Performance of Cements(Hindawi, 2023-11) Muthengia, Jackson Wachira; Munyao, Onesmus Mulwa; Mutitu, Daniel Karanja; Musyoki, David MunyaoGrinding aids (GAs) are polar chemicals introduced in cement mills in either liquid or powder form to improve on mill grindability efficiency. Studies have shown that some GAs not only help in grinding efficiency but also play vital roles in improving the product particle size distribution, product ability to flow in the mill, grinding energy reduction, and improvement on the separator efficiency. This review investigated the impacts of the GAs on the performance of some properties of cement when used as either mortar and/or concrete. The influence of the GAs incorporation in cement grinding on properties such as workability and setting times of the placed concrete and/or mortar has been covered in this review. The performance of GAs on ordinary portland cement (OPC) and blended cements with other supplementary cementitious materials such as pozzolana, fly ash, and slag has also been discussed. This is in view to tapping the maximum benefits of using GAs in cement production and use. This review work established that GAs have a positive influence on mill performance when properly applied. It further established that blended cements work better when dosed with additives such as GAs and/or quality improvers when compared to OPC. The review work demonstrated that some superplasticizers help in lowering the water demand in highly blended pozzolanic-based cements. The review finally recommended that the future course of action in the production of blended cements should apply GAs. This is in order to help produce highly replaced blended cements that are sustainable.Item Antimicrobial Activities of Some Constituents Isolated from a Kenyan Medicinal Plant, Capparis fascicularis DC(Hindawi, 2023-10) Kagika, Mary W.; Chhabra, Sumesh C.; Nonoh, James O. M.; Hassanali, AhmedBackground of the Study. Capparis fascicularis DC. is an indigenous medicinal plant belonging to the family Capparaceae found in Nyandarua County, Nairobi, Kenya, and many parts of Africa. It is a shrub whose roots are used traditionally to treat colds. Aim. The aim of the present study is to carry out antimicrobial activities of solvent extracts of diferent parts of Capparis fascicularis, characterize the phytochemical constituents of the most active extract, and identify the most active compounds. Place and Duration of the Study. All the experiments were carried out in the departments of Chemistry and Microbiology, Kenyatta University, Nairobi, Kenya. Methodology. Petroleum ether, ethyl acetate, methanol, and water extracts from the leaves, stem bark, and root bark of C. fascicularis were screened against selected strains of both Gram-positive (Staphylococcus aureus and Bacillus subtilis) and Gram-negative (Salmonella typhimurium and Escherichia coli) bacteria using disc difusion and tube dilution methods. Fractionation of the most active crude extract was carried out by column chromatography, and the fractions together with the most active crude extract were screened against the selected bacterial strains. Te most active fraction was further fractionated, and the subfractions were screened against the bacterial strains to test for possible synergistic efects between the subfractions and their constituents. Te most active fraction was then analysed by GC-MS and LC-ESI-MS methods to identify the major constituents. Results. Te ethyl acetate extract of C. fascicularis root bark (CFR2) showed a signifcant in vitro antibacterial activity. From the seven fractions of CFR2 obtained, fraction 2 (F2) had the lowest MIC value and was thus most active. Moreover, F2 was found to be more active compared to the four subfractions obtained from it. Tis suggested that constituents of F2 worked in synergy. Fraction 2 contained phenols, terpenes, and favonoids. Two compounds were identifed by GC-MS as 2,4-di-tert-butylphenol and (E,E)-2,4-decadienal, while three compounds were identifed by LC-ESI-MS as tanshinone II A, cryptotanshinone, and danshensu. Conclusion. Te study revealed that CFR2 is the most active extract on bacteria, suggesting that most antimicrobial compounds are concentrated in the roots of C. fascicularis. A follow-up study is directed towards chromatographic separations to obtain the other chemical constituents and screen them against various strains of bacteria.Item Ethnobotany of Some Members of the Genus Cassia (Senna)(Novelty Jourrnals, 2023-09) Osunga, Salome; Amuka, Omari; Machocho, Alex K.; Getabu, AlbertThe Genus Cassia, also known as Senna, is a large group of leguminous plants belonging to the family of Fabacea. They have a wide range of ethnobotanical uses, including medicinal, ornamental, and industrial applications. In traditional medicine, the Genus has been used in the treatment of various diseases all over the world. Various pytochemicals with diverse bioactivities have been isolated from the Cassia species. However, this has not been done exhaustively in all the species. This review relates the ethnobotanical uses of various Cassia species and emphasizes the importance of doing scientific research on these secondary metabolites for the benefit of the general public.Item Comparative Responses of Ovipositing Anopheles Gambiae and Culex Quinquefasciatus Females to the Presence of culexegg Rafts and Larvae(Medical and Veterinary Entomology, 2010-11) Wachira, W.; Ndung’u, M.; Njagi, P.G.N.; Hassanali, A.Field observations have demonstrated that gravidAnopheles gambiaeGiless.s. (Diptera: Culicidae) are selective in their choice of oviposition sites. Forexample, immature stages ofAn. gambiae s.s.are rarely found in water that containsCulex quinquefasciatusSay immatures. The possibility that this may, in part at least,reflect a response by ovipositingAn. gambiae s.s.females to volatile signals associatedwithCulexjuveniles was evaluated by testing the response ofAn. gambiae s.s.femalesto varying densities ofCx. quinquefasciatusegg rafts and/or larvae in ovipositionchoice assays. For comparison, the oviposition choices ofCx. quinquefasciatusto conspecific egg rafts and/or larvae were similarly assayed. At a low densityofCx. quinquefasciatusegg rafts (1–15 egg rafts/100 mL water),An. gambiae s.s.females laid more eggs in the treatment water than in the control, with a maximumof twice as many in the treatment water at 5 egg rafts/100 mL water. At higheregg raft densities and in all treatments that includedCx. quinquefasciatuslarvae,oviposition decreased significantly in the treatment dishes in a density-dependentmanner. As previous studies have indicated, ovipositingCx. quinquefasciatusfemaleswere attracted to and laid egg rafts in dishes containing conspecific egg rafts and,interestingly, also in dishes containing larvae.Item Novel Cross-Stage Solitarising Effect of Gregarious-Phase Adult Desert Locust (Schistocerca Gregaria (Forska ˚l)) Pheromone on Hoppers(Elsevier Ltd, 2010-01) Bashira, Magzoub O.; Hassanali, AhmedPrevious studies had demonstrated stage differentiation in the cohesion (aggregation) pheromone systems of the desert locust, Schistocerca gregaria. In laboratory arena, the nymphal and adult stages responded aggregatively to their own pheromone, but dispersed evenly within the arena in the presence of the other. In the present study, we explored the effects of longer-term contact of field gregarious hopper bands and laboratory crowd-reared nymphs with the major constituent of the adult pheromone. During the first few days, hoppers in treated bands became relatively hyperactive. Over the next few days, their movements became random and they stopped marching as coherent groups, they started to roost for longer periods on vegetations, and they fragmented into smaller and smaller groupings and individuals. When attacked by birds, they demonstrated subdued levels of collective defensive behaviour compared to normal hoppers, and there were clear signs of increased predation and cannibalism at the roosting sites. In cage experiments, crowd-reared nymphs treated with the pheromone component became hyperactive, showed abnormal diel patterns and reduced feeding on plants but increased cannibalism. Our observations show that the major adult pheromone constituent has asolitarising effecton gregarious hoppers. The mechanism underlying this effect and the potential of the agent in desert locust control are discussed.Item Antimosquito and Antimicrobial Clerodanoids and A Chlorobenzenoid from Tessmannia Species(Natural Product Communications, 2009-08) Kihampaa, Charles; Nkunya, Mayunga H.H.; Joseph, Cosam C.; Magesad, Stephen M.; Hassanalic, Ahmed; Heydenreiche, Matthias; Kleinpeter, ErichThe clerodane diterpenoids trans-kolavenolic acid, 18-oxocleroda-3,13(E)-dien-15-oic acid, ent-(18-hydroxycarbonyl)-cleroda3,13(E)-dien-15-oate, 2-oxo-ent-cleroda-3,13(Z)-dien-15-oic acid and trans-2-oxo-ent-cleroda-13(Z)-en-15-oic acid, and the chlorobenzenoid O-(3-hydroxy-4-hydroxycarbonyl-5-pentylphenyl)-3-chloro-4-methoxy-6-pentyl-2-oxybenzoic acid were isolated from Tessmannia martiniana var pauloi and T. martiniana var matiniana. Structures were established based on interpretation of spectroscopic data. Some of the compounds exhibited significant antimosquito, antifungal and antibacterialItem Biological cost of tolerance to heavy metals in the mosquito Anopheles gambiae(National Institute of Health, 2010-06) Mireji, P. O.; Keating, J.; Hassanali, A.; Mbogo, C. M.; Muturi, M. N.; Githure, J.I.; Beier, J.C.The global rate of heavy metal pollution is rapidly increasing in different habitats. Anopheles malaria vector species appear to tolerate many aquatic habitats with metal pollutants, despite their normal proclivity for ‘clean’ water (i.e., generally water free of organic matter). Investigations were conducted to establish whether there are biological costs for tolerance to heavy metals in Anopheles gambiae Giles sensu stricto (Diptera: Culicidae), and to assess the potential impact of heavy metal pollution on mosquito ecology. Anopheles gambiae s.s. were selected for cadmium, copper or lead tolerance through chronic exposure of immature stages to solutions of the metals for three successive generations. Biological costs were assessed in the fourth generation by horizontal life table analysis. Tolerance in larvae to cadmium (as cadmium chloride, CdCl2), copper (as copper II nitrate hydrate, (Cu (NO3)2. 2·5H2O) and lead (as lead II nitrate, (Pb (NO3)2), monitored by changes in LC50 concentrations of the metals, changed from, 6.07, 12.42 and 493.32 μg/L to 4.45, 25.02 and 516.69 μg/L, respectively, after 3 generations of exposure. The metal- selected strains had a significantly lower magnitude of egg viability, larval and pupal survivorship, adult emergence, fecundity and net reproductive rate than the control strain. The population doubling times were significantly longer and the instantaneous birth rates lower in most metal- selected strains relative to the control strain. Our results suggest that although An. gambiae s.s. displays the potential to develop tolerance to heavy metals, particularly copper, this may occur at a significant biological cost, which can adversely affect its ecological fitnessItem Adsorption of Lead (ii), Chromium (vi) and Manganese (ii) metal ions from water using modified Pennisetum purpureum Schumach plant stalk(2022) Murage, D.; Masika, E.; Wanyonyi, W. A.Water pollution is a global problem affecting humanity. Availability of clean water is a fundamental prerequisite to public health safety and the survival of the human race as well as animals. However, pollution of river water by heavy metal ions deposition is a grave environmental problem. Presence of the heavy metals in the water, pose a serious health risk particularly to rural populations which rely majorly on the river water for domestic purposes. Several methods for elimination of the heavy metal pollutants from river waters have been previously employed. However, most of these methods are expensive and cumbersome, hence not sustainable. This research explored the potential of modified Pennisetum purpureum Schumach plant adsorbent in removal of Lead (II), Manganese (II) and Chromium (VI) ions from spiked water samples by adsorption. Surface analysis of the adsorbent using FTIR Photometer confirmed presence of functional groups such as -NH2, C=O and O-H responsible for adsorption of heavy metal ions. Concentration of heavy metal ions in water samples was determined before and after adsorption process using Atomic Absorption Spectroscopy (AAS) and means concentration computed. Effect of changes in pH on adsorption was investigated by conducting adsorption at three different pH conditions of 5, 7 and 9. Modification of the adsorbent surface improved its adsorption capacity. For instance, at pH 5, adsorption of Cr+6 increased from 12% to 14.82% when modified adsorbent was used. The modified adsorbent achieved greater % adsorption in all the three metals. Increase in the pH of adsorption from 5 to 9 had a reducing effect on the percent adsorption. At pH of 5 the % adsorption of Pb+2 reduced from 90.26% to 73.75% at pH of 9. This reductions in percentage adsorption were recorded for Pb+2 and Mn+2 ions but not significant for Cr+6 ions. These results show the potential of P. purpureum plant for use as an adsorbent in purification/detoxification of river water which would present a cheaper and more readily available alternative to many current adsorbents and adsorption methods in use. However further research is needed to determine the optimal set of conditions as well as the most suitable modification treatment for maximum adsorptionItem Effects on Nanaofertilizers on Cd AND Pb Uptake in Kales Grown in Medially Polluted Experimental Soil.(IOSR Journal of Applied Chemistry (IOSR-JAC), 2020-03) Ngorwe, E.N.; Nawiri M.; Murungi J.; Nyambaka H.; Ongera T.Background: Most agriculturalists use excess commercial fertilizers with the notion that some will be eroded and leached eventually causing eutrophication and alters soil pH that increases Cd and Pb uptake in crops .Nanoparticles have numerous adsorption sites that reduce Cd and Pb uptake in crops and it has controlled release of nutrients guaranteeing longer interaction with the crops to ensure safer and higher crop yields to feed sporadic growing population. Materials and Methods: This study uses nanohydroxyapatite adsorbents from waste bones to synthesis nanofertilizers by encapsulating with DAP and NPK commercial fertilizers. Pots study in green house for contaminated soils were conducted with eight treatments in triplicate; DAP added, NPK added, NPK-DAP added, DAP nanofertilizer, NPK nanofertilizer, NPK-DAP nanofertilizer and non-treated control (ck) treatments, for sukuma wiki (kales) in Kitutu Chache south sub-county, Kisii County, Kenya. Nine pots were set for each treatment with one seedling each planted per pot. Nanofertilizers were applied at normal application rates during planting. Crops were left grown for 30 days to 90 days until they matured and harvested three times on a monthly basis. Harvested leaves were washed with distilled deionized water, oven dried and then acid digested and then analyzed by AAS for Cd and Pb. Data obtained was analyzed by ANOVA and t-test to compare means of various treatment, Cd and Pb in contaminated soils. Results: The nanofertilizers treatment recorded lowest levels of Cd and Pb in sukuma wiki harvested leaves. The bone ash (nHA added) had the lowest concentration levels of Cd (18.14±0.29) and Pb (15.91±0.57) with NPK nanofertilizers also recording lower concentration levels of Cd (27.29±0.50) and Pb (21.59±0.74). The DAP added fertilizers recorded highest concentration levels of Pb (56.74±5.75) while NPK added fertilizers recorded highest concentration levels of Cd (53.46±2.55). The bone nanofertilizer grown sukuma wiki had higher growth performance and lower levels of Cd and Pb to the permissible levels allowed by WHO/FAO in Kenyan vegetables. The bone ash nano treatment posted the lower heavy metals concentration levels of Cd (18.14±0.29) and Pb (15.91±0.57) while in synthetic experiments leaves harvested from synthetic ash nanofertilizer treated pots had Cd (23.71±1.92) and Pb (14.60±0.30). Cadmium concentration levels in kales harvested from bone ash recorded the highest reduction of 60.69% as compared with the non-treated control followed by bone NPK nanofertilizer with 30.70% cadmium uptake reduction. Lead uptake in bone set-up was most efficiently reduced by bone ash (nHA) by 59.25% while reduction by same treatment in synthetic experiment was 58.71%. The bone NPK nanofertilizer had 44.70% lead uptake reduction. However fertilizer amendment increased lead uptake with DAP added treatment hiking lead uptake in kales by 14.04%. Conclusion: The result is recommended for nanofertilizers to be used in growing other crops such as maize, beans, spinach potatoes, wheat, rice and other vegetative crops in medially polluted soils, especially in periurban farming to boost food productivity to feed ever growing population.Item Characterization of Flavonoids from Candidate Striga Grass in Controlling Diet Legumes Cicer Arietinum and Vigna Radiata(BIOFARMASI J NAT PROD BIOCHEM, 2018-08) Akumu, Anyango Anna; Nyambaka, Hudson; Kuate, Serge Philibert; Torto, BaldwynAkumu AA, Nyambaka H, Kuate SP, Torto B.2018. Characterization of flavonoids from candidate striga grass in controlling diet legumes Cicer arietinum and Vigna radiata.Biofarmasi J Nat Prod Biochem 16: 83-98. In Africa, intercropping of some legumes with cereal plants has been noticed to generate exceptional reduction of Striga invasion and enhanced production of cereal crop. Desmodium uncinatum administers Striga invasion in intercrop with cereals through an allelopathic technique, which includes post-sprouting accretion inhibitors emanated from the roots. Having a potential to be a new technique for grass administering, Allelopathy is a natural and environmentally friendly method. A standardized profiling technique based on Reverse Phase-High Performance Liquid Chromatography (RP-HPLC) and Liquid Chromatography coupled with Mass Spectrometry (LC/MS) was utilized to determine flavonoids in extracts of chickpea (Cicer arietinum) and mung bean (Vigna radiata), potential trap plants for Striga grass. Nine flavonoids involving mono-and diglycosyl derivatives of fisetin, baicalein, rhamnetin, isorhamnetin, formononetin, quercetin, isosakuranetin, and sakuranetin were temporarily distinguished. The obtained phenolics were available at concentrations higher than 0.001% of the dry materials. Many of these phenolic mixtures have been claimed to possess human health advantages. These glycosylated flavones are noted for the first time in these two species. The comprehensive analysis of the polar secondary metabolites in these leguminous plants was useful for comprehending their inhibitory chemistry and proposed biosynthesis by C-glucoside characteristics. All the segregated and described mixtures in the diet legume C. arietinum were O-glucosylated. While, Food legume V. radiata should be observed further to see if it can attain Desmodium’s allelopathic ability since it possesses inhibitory chemistry and proposed biosynthesis by C-glucosylation.Item Antimicrobial Photodynamic Activity of Phthalocyanine Derivatives(Hindawi, 2018) Nyamu, Samuel N; Ombaka, Lucy; Masika, Eric; Ng’ang’a, MargaretMicrobial pathogens have increasingly shown multidrug resistance posing a serious threat to the public health. Advances in technology are opening novel avenues for discovery of compounds that will mitigate the ever-increasing drug-resistant microbes. Use of photodynamic photosensitizer is one of the promising alternative approaches since they ofer low risk of bacteria resistance as they use generated reactive oxygen species to kill the microbes. Phthalocyanine (Pc) is one such photosensitizer which has already shown promising antimicrobial photodynamic therapeutic properties. Previous studies have shown efectiveness of the Pc against Gram-positive bacteria. However, its efectiveness toward Gram-negative bacteria is limited by the impermeability of the bacteria’s outer membrane which is made up of lipopolysaccharides layer. Te efectiveness of this photosensitizer is determined by its photophysical and photochemical properties such as singlet/triplet lifetimes, singlet oxygen quantum yields, and fuorescence quantum yield. Terefore, this review focuses on the recent signifcance advances on designing Pc that have this improved property by either conjugating with nanoparticles, quantum dots, functional groups in peripheral position, considering efect of cationic charge, and its position on the macrocycle.