Screening for Bioactive Extracts and Targeted Isolation of Antimicrobial Agents from the Stem Bark of Adenanthera pavonina L.

Abstract

Bioactive secondary metabolites can be isolated from medicinal plants as antimicrobial agents. Based on ethnopharmacological relevance, Adenanthera pavonina L. is recognized as a plant with good medicinal values and forms the integral part systems of traditional medicine in Borno state, and other parts of Nigeria. Despite the widespread used, most of the information available to consumers about the plant is not backed by credible scientific data. Only a limited number of studies have probed into the scientific evidence for bioactivity and safety of this medicinal plant. Such studies rarely progress to isolation and evaluation of the active antimicrobial agents. In the present study, four solvent-extract (ethanol, ethyl acetate, chloroform and n-hexane) were subjected to antimicrobial activity test against E. coli (E.C), S. typhi (S.T), S. aureus (S.A), A. flavus (A.F), C. albican (C.A) and M. specie (M.S) and toxicity test against Artemia salina. The ethyl acetate extract showed outstanding activity against the microbes (bacteria and fungi) and Artemia salina, respectively. The activity and toxicity effects of the ethyl acetate extract suggests the presence of active antimicrobial agents and hence provides a way forward for column chromatographic isolation of the targeted Antimicrobial agents. The targeted compounds isolated (AP-X38 and AP-X44) were also subjected to antimicrobial test using three bacterial species and found to be even more active that the solvent extract of ethyl acetate. This study justifies part of ethno medicinal claims on the plant.