Evaluation of Antibacterial Activity and Phytoconstituents of the Aqueous Leaves Extract of Alchornea Cordifolia

Abstract

Alchornea cordifolia Schum and Thonn. (Euphorbiaceae) is a plant widely used in traditional medicines of Ghana for the treatment of skin and other infections. This study evaluated the antibacterial properties and phytoconstituents of the aqueous leaves extract of A. cordifolia with particular reference to methicillin-resistant Staphylococcus aureus (MRSA). Minimum inhibitory and bactericidal concentrations (MIC and MBC) of the aqueous leaves extract of the plant were evaluated against 32 clinical isolates of MRSA and controls by the microdilution technique in Iso-sensitest broth. Growth and time-kill curves were also carried out using spectroscopy at 490 nm and viable cell counts method. Mean diameter of zones of inhibition ranged 18-30 mm of the aqueous extract of the plant were found against MRSA. MIC and MBC values ranged 1.6-3.1 mg/ml and 6.5-12.5 mg/ml of the aqueous leaves extract of A. cordifolia were found against the 32 clinical isolates of MRSA with most of the strains having MIC value of 3.1 mg/ml and MBC value of 12.5 mg/ml. Growth and time-kill curves indicate bacteriostatic activity of the plant extract on MRSA. Phytochemical analysis of the extract showed low concentrations of alkaloids and saponins but very high concentrations of tannins present in the leaves of the plant. From the results of the study, aqueous leaves extract of A. cordifolia may contain antibacterial compounds that justify its usage in traditional medicine.