Phytochemical Evaluation of Tephrosia Hildebrandtii For Antimicrobial Principles

Abstract

Pathogenic diseases caused by microbes are a main public health problematic around the world causing death. Medicinal plants contain bioactive compounds (metabolites) that serve an important therapeutic role in curing and healing human maladies caused by these microbes. Plant metabolites such as flavonoids have been reported to display antimicrobial properties against some strains of microbes. The genus Tephrosia (Fabaceae) is known to be rich in flavonoids. In this study, flavonoids and other secondary metabolites from the aerial parts of Tephrosia hildebrandtii were isolated, characterized and assayed for their antimicrobial activities. The investigation of phytochemicals the aerial parts of this plant led to the isolation of four flavone derivatives, a sterol, a triterpene and a carotenoid. One of the isolated compounds is new and the structures were established using a combination of techniques including NMR, UV and MS. Both the crude extract (MeOH/CH2Cl2 1:1 v/v) and the isolated compounds were tested for antimicrobial activity against Escherichia coli, Bacillus cereus and Candida albicans. The crude extract, compounds 1 and 2 showed significant activity against Escherichia coli. The crude extract and compound 1 also exhibited good activity against Candida albicans, while compounds 4, 5 and 6 showed moderate activity. Compound 1 and a mixture of compounds 2 and 3 showed moderately good activities against Bacillus cereus, while the crude extract and compound 2 were moderately active. Compound 4 was treated with hydrazine hydrate and guanidine hydrochloride in presence of alkali to yield a new pyrazoline derivative 8 and a new guanidine derivative 9, respectively. Both derivatives showed activities against the tested bacterial and fungal strains. Compound 8 showed not only the highest antifungal activity against C. albicans compared to compound 9, it also was the most active on the gram negative and gram positive bacteria tested........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................