Chromatographic Analysis of Ethanol Extract of Funtumia elastica leaves and stem bark and their antimicrobial activity

Abstract

The study evaluated the antimicrobial activity based on chromatographic analysis of ethanolic extract of Funtumia elastica leaves and stem bark. Funtumia elastica leaf and stem bark samples were air dried, grinded and extracted in ethanol by soxhlet extraction. The defatted ethanol extract was partitioned in dilute sodium hydroxide, hydrochloric acid and chloroform to obtain basic, neutral and acidic metabolites. The phytochemical test on the defatted crude extract of Funtumia elastica leaf and stem bark show the presence of tannins, alkaloids, flavonoids, saponins, terponoids, anthraquinone, phenolics and steroids. The crude extract, basic, neutral and acidic metabolites, and the fractions obtained by thin layer chromatography were screened for their antimicrobial activity at concentration of 100mg/ml against Streptococcus pneumoniae(sp), Staphylococcus aureus(sa), Salmonella typhi(st), Escherichia coli(ec) and Candida albicans(ca). The results show that the crude extract of stem with inhibition zone diameter(mm) of 22, 18, 20, 22 and 20 against (sp), (sa), (st), (ec) and (ca) respectively had better antimicrobial activity than the crude extract of leaf with inhibition zone diameter(mm) of 16,10,16,14 and 12 against (sp), (sa), (st), (ec) and (ca) respectively. Also the TLC fractions exhibited lower antimicrobial activity when compared to that of the basic metabolites. The fractions obtained by thin layer chromatography which showed promising antimicrobial activity were analysed by gas chromatography mass spectroscopy (GC/MS). The GC/MS spectra revealed thirty-nine peaks from which thirty nine compounds were identified. The identified compounds were mainly carboxylic acids and esters. The results of antimicrobial screening show that the crude extracts of the stem bark with inhibition zone diameter (mm) of 22, 18, 20, 22 and 20 were comparable to the standard drugs ciprofloxacin with inhibition zone diameter (mm) of 18, 20, 20, and 15 and gentamycin with inhibition zone diameter (mm) of 10, 20, 15, 12, and 18.