Antimicrobial of extract and compounds from the bark of Drypetes afzelii (Pax) Hutch

Abstract

The objective of the present study is to evaluate in vitro the antimicrobial activities of the extract and compound of Drypetes afzelii used in Cameroonian medicine. The evaluation of the antibacterial and antifungal activities was determined on eighteen of microorganisms which 6 Gram-positives bacteria, 10 Gram-negatives bacteria and 2 fungi. This study focused on the determination of the Minimal inhibition and microbicidal concentrations. Nystatin and Gentamicin were used as reference antibiotics. The fractionation was realized by chromatographic methods (TLC, HPLC, MPLC) and the structures of the isolated compounds were established using spectroscopic analysis (one and two-dimensional nuclear magnetic resonance (NMR). Five compounds were isolated from the bark of Drypetes afzelii whose namely the terpenoid (lupeol), lignan (sesamin) and flavonoids (Acacetin, Isosakuranetin, 5,7,4’-trihydroxyflavanone). The most sensitive bacteria were Bacillus stearothermophilus and Klebsiella pneumoniae with MIC values 20.1-20.2 µg/mL for Bacillus stearothermophilus and 20.2 µg/mL for Klebsiella pneumoniae. The MMC values of 25.2-40.3 µg/mL for Citrobacter freundii and 40.3 µg/mL for Klebsiella pneumoniae. The results indicated that this plant has great interest for the future production of the new drugs against infectious diseases.