Cytoxicity and antimicrobial activity of methanol extract and fractions of Entandrophragma angolense (Welw) C. Dc. (Meliaceae) Leaves

Abstract

The antibacterial activity and brine-shrimp lethality (BSL) assay of methanol extracts of Entandrophragma angolense, used to treat gastro-intestinal tract (GIT) infections in South-Western Nigeria was investigated. The extract and chromatographic fractions were tested at 20 and 10 mg/in! respectively against Staphylococcus aureus (ATCC 25923), Pseudomonas aeruginosa (ATCC 27853). Salmonella typhi (clinical isolate), Salmonella typhimurium ATCC 14028, Escherichia coli (ATCC 25922) and Bacillus subtilis (ATCC 6633) using agar-well diffusion method. Minimun Inhibitory Concentrations (MIC) were determined by agar dilution method. Further, the extract was fractionated on silica gel (70-230 mesh) using column chromatography. The diameter of zois of inhibition were between 15.0-30.5mm which vas comparable with gentamicin (10μg/ml) used as control. The MIC was 80.0μg/ml on Staph. aurer: and 350μg/ml on Salmonella typhi. The more polár fractions contained the antimicrobial compou de as the less polar fractions showed no antimicrobial activity as tested. Phytochemical screening revealed the presence of tannins, flavonoids, reducing sugars and steroidal compounds. Brine shrimp lethality assay gave a value of 62.5μg/ml. Therefore E. angolense leaves contains antimicrobial agents and cytotoxic principles to justify its folkloric uses and phytotherapeutic potentials in treating infections.