Background: Plants are new sources of antibacterial agents, hence the need to determine and evaluate the antibacterial properties, antioxidant activity and gas chromatography – mass spectrometer (GC-MS) profile of medicinal plants. Methodology: In this study, sequential extraction of Prunus africana and Harrisonia abyssinica was used to obtain ethyl acetate and methanol extracts. Antioxidant activity was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH), whereas the total phenolic and total flavonoid contents were estimated using Folin-Ciocalteu and aluminium chloride, respectively. Antibacterial properties of the extracts against Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa, Escherichia coliand Candida albicans were estimated using the disc diffusion method and compared against streptomycin. Results: Screening of crude methanolic extracts revealed the presence of secondary metabolites which was further confirmed by Fourier transform infrared (FT-IR) characterisation that revealed the presence of H-bonded OH functional groups. The extracts revealed that P. africana had a higher total phenolic and total flavonoid contents compared to H. abyssinica. Methanolic extracts of both plants had moderate activity against selected microorganisms and both inhibited DPPH radical scavenging activity. GC-MS analysis of P. africana and H. abyssinica extracts revealed the presence of several phytochemicals that have been reported to have medicinal uses. Total phenolic and flavonoid contents showed positive correlations with the DPPH radical scavenging activity and negative correlations with EC50. Conclusion: Prunus africana and H. abyssinica extracts had moderate antimicrobial properties against the selected microorganisms because of the presence of secondary metabolites.

Aim: This study assessed the levels of Pb, Cr, Cd and Zn in settled indoor dust and paint chips. Study Design: Samples were obtained from twelve selected residential houses within Nairobi County, Kenya.

Wild indigenous vegetables make considerable contributions to food baskets among subsistence farmers in sub‐Saharan Africa. The aim of this study was to evaluate the proximate analysis, mineral composition, vitamin C content, β‐carotene content, and GC‐MS profile of crude methanolic extracts of Asystasia mysorensis and Sesamum angustifolia . Crude extracts obtained through sequential extraction using ethyl acetate and methanol were screened for the presence of secondary metabolites. Functional groups present were determined with a Shimadzu FT‐IR spectrophotometer, while β‐carotene content and ascorbic acid content were evaluated using a Shimadzu HPLC and Shimadzu UV‐VIS spectrophotometer, respectively. Secondary metabolites present in the extracts were determined qualitatively using a Shimadzu GC‐MS system equipped with a NIST spectral database. From the results obtained, the two plants could supply the recommended daily requirement for micronutrient and vitamin C content needed for a healthy diet. The total phenolic and flavonoid contents in S. amgustifolia were higher as compared to A. myorensis; hence, their consumption is highly beneficial as some compounds identified in the GC‐MS profile have been reported to have medicinal properties. The findings on the mineral and chemical composition, GC‐MS profile of A. mysorensis and S. angustifolia indicate that their consumption may provide the recommended nutritional requirements needed for a healthy diet.

Water samples were taken from five sampling points and their quality assessed through analysis of physical and chemical characteristics. Turbidity, temperature, conductivity, pH, dissolved oxygen and total suspended solids were determined on site during sample collection, using potable meters. Anions were determined using UV/Visible spectroscopy while heavy metals were determined using flame Atomic Absorption Spectroscopy (AAS) in accordance with AWWA standard methods. Turbidity was the highest recorded parameter during the wet season with a mean of 481.83 NTU. 53% of the parameters showed significant seasonal variation (P<0.5) with the mean concentration of 56 % of the parameters being higher during the wet season. The parameters that exceeded the WHO limit were turbidity, phosphates, lead, iron, nickel, chromium and cobalt indicating poor quality of water in River Sio. Poor agricultural practices, domestic and industrial wastewater are the main factors that contribute to pollution of the River. The study proposes proper land use, proper treatment and disposal of sewage and use of organic manure and biological control as means of preventing water and soil pollution.

Agricultural activities, discharge of raw sewage into farms and the rise in urbanization have greatly contributed to soil pollution. During the rainy season, surface runoff from farms find their way into water bodies and deposits these contaminants into Rivers and Lakes which poses a threat to both aquatic and terrestrial organisms that depend on that water source. The objective of this research was to determine the level of anions and heavy metals from sediments in River Sio, Busia County, Kenya. Five sediment samples were taken from five sampling points and the levels of anions and heavy metals in them determined. Anions were determined using Shimadzu 1800 UV/visible spectrophotometer while heavy metals were determined using Shimadzu 6200 flame atomic absorption spectrophotometer (AAS). Copper, lead and nickel were above the allowed WHO limits while cadmium was below detection limit. The levels of nitrates, phosphates and chlorides were higher during the wet season due to surface runoff that carried these nutrients from the farms and deposited them on the bottom of the River. The levels of heavy metals were high during the dry season due to evaporation of water from the River, leading to an increase in the analyte concentration during the dry season. High levels of copper and nickel in the sediments points to the use of herbicides and pesticides in farming and washing of vehicles and motorcycles on the banks of the River. According to Igeo nickel showed moderate pollution during the dry season. The contamination factor for lead was very high during the dry season, while pollution load index confirmed pollution due to anthropogenic activities in sampling sites 1 – 4 during the dry season and no pollution due to anthropogenic activities during the wet season.  The study recommends reduced use of inorganic fertilizers in order to save the River from the danger of eutrophication. Excessive use of agrochemicals such as herbicides and pesticides should be discouraged. In addition, pesticide leaching and the level of microbes in soil and sediments should be considered for further research