Antimicrobial Investigations, Phytochemical Constituents and Cytotoxicity Evaluation of Acokanthera Schimperi (a. Dc.) Schweinf. Leaves Crude Extract

Abstract

Phytomedicine, a significant area of study and an intervention towards alleviation of mankind and animal suffering using ethnomedicine and ethnoveterinary approaches, has catapulted bioprospection in drug discovery. This strategic approaches have led to our cynosure on Acokanthera schimperi (A. DC.) Schweinf. (Apocynaceae family). In the study, botanical identification and collection of plant voucher specimen was done in the company of both an herbalist and a Taxonomist. The latter was then deposited in the University of Nairobi Herbarium, School of Biological Sciences, Chiromo Campus where a voucher specimen number was issued. Approximately 5kg leaves of the study plant were sampled from several shrubs and transported to the Department of Pharmacology and Toxicology, University of Nairobi, College of Agriculture and Veterinary Services. Shade drying for two weeks was done after which, the leaves were pulverized using Chrisky Hunt machine 800 laboratory Mill at LARMAT to fine powder. About 4.5 grams of the dried powder was divided and put in three separate large conical flasks into which respective solvents were added. Hydroethanolic (50:50), distilled water and acetone (analytical grade) were the extraction solvents of choice. The conical flasks were air-tightly corked and put in a dark chamber for 24 hours to allow for extraction. Corresponding extracts obtained were labelled Hydroethanolic, Aqueous and Acetone extracts respectively. The determination of the extracts’ cytotoxicity, antimicrobial activity and qualitative phytochemistry was done. The in vitro antimicrobial activity of the extracts were tested against standard reference organisms viz. Escherichia coli (ATCC 25922), Staphylococcus aureus (ATCC 25923), Pseudomonas aeruginosa (ATCC 27853), Bacillus cereus (ATCC 11778) and Candida albicans (ATCC 102231). Moreover, the safety of the generated extracts was evaluated using the BSLA using Artemia salina Leach. Qualitative phytochemistry analysis was also included in the study so as to identify secondary metabolites present in the extracts...