PHARMACOGNOSTIC AND ANTIMICROBIAL STUDIES ON THE STEM-BARK OF FICUS KAMERUNENSIS WARB. (MORACEAE)

PHARMACOGNOSTIC AND ANTIMICROBIAL STUDIES ON THE STEM-BARK OF FICUS KAMERUNENSIS WARB. (MORACEAE), A RESEARCH PROJECT TOPIC ON MICROBIOLOGY

ABSTRACT

Ficus kamerunensis is an epiphytic shrub or tree growing up to 20 m high. The plant used in ethnomedicine to treat microbial infections such as sexually transmitted infections. Pharmacognostic studies were conducted on the fresh and dried whole stem-bark of F. kamerunensis. The quantitative physical standards were carried out. Preliminary phytochemical screenings of the powdered stem bark of the plant were conducted using appropriate chemical reagents. The powdered stem bark (1 kg) of the plant was extracted using cold maceration technique with 3 L of 95% methanol in a glass jar for 3 days (72 hours) at room temperature, then partitioned with diethylether, ethyl acetate and n-butanol. Thin-layer chromatography was carried out using diethyl ether fraction to obtain the best solvent system to be used for column chromatography. A combination of column chromatography and preparative thin layer Chromatography using Column chromatography were carried out using the best solvent system obtained (Hexane: Ethyl acetate 7:3) for compound isolation. The structure of the isolated compound was determined by the analysis of ¹H NMR, ¹³C NMR, and 2D NMR spectral data, as well as comparison with reported data. Antimicrobial evaluations of the stem-bark of the plant were carried out for diethyl ether, ethyl acetate, n-butanol and 95% methanol extract at different concentrations (50, 25, 12.5, 6.25 and 3.125 mg/ml) and tested against four Gram-positive bacteria—Staphylococcus aureus, Streptococcus pyrogenes, MRSA, and Neisseria gonorrheae, and four Gram-negative bacteria—Corynebacterium ulcerans, E. coli, Pseudomonas aeroginosaand Proteusmirabilis as well as four fungi— Candida albicans, Candida krusei, Candida stellatoidea and Candida tropicalis. Mc-farland’s turbidity standard scale (number 0.5) was used to standardize the test micro organisms. Agar Diffusion method was used to screen the extracts while the minimum inhibitory concentrations (MIC) as well as minimum bactericidal and fungicidal concentrations (MBC/MFC) were determined using broth dilution method.The acute toxicity studies (LD₅₀) was carried out using Lorke method. Phytochemical screening of the powdered stem-bark of Ficus kamerunensisreveals the presence of carbohydrates, anthraquinones, saponins, cardiac glycosides, terpenoids, flavonoids, tannins and alkaloids. Physicochemical studies showed moisture content, total ash acid insoluble ash, water soluble ash, alcohol extractive and water extractive values of 11.7, 8.8 1.7, 3.7, 10.4 and 18.4 % respectively. Antimicrobial evaluation shows that the extracts have activity against E. coli, Candida albican, Candida stellatodea, Corynebacterium ulcerans, MRSA,Neisseria gonorrhea, Pseudomonas  aeroginosa  Staphylococcus  aureus  while  Candida  tropicalis, Candida  krusei, Proteus mirabilis and Streptococcus pyrogens were resistant to the tested extracts. Known compound (pentacyclic triterpene) α-amyrin acetate was isolated and characterized from the diethyl ether fraction of the methanol extract of the plant material.

CHAPTER ONE

1.0 INTRODUCTION

The World Health Organization (WHO) estimates that up to 80% of the population in Africa make use of traditional medicine as well as about 65% of the world’s population (Fabricant and Farnsworth, 2011). Plants used in traditional medicine, also called phytomedicine are plant-derived medicines that contain chemicals, more usually, mixtures of chemical compounds that act individually or in combination on the human body to prevent disorders and to restore or maintain health (Van- Wyk, et al,1997).

PHARMACOGNOSTIC AND ANTIMICROBIAL STUDIES ON THE STEM-BARK OF FICUS KAMERUNENSIS WARB. (MORACEAE), A RESEARCH PROJECT TOPIC ON MICROBIOLOGY