Phytochemical Study and Antibacterial Properties of the Leaf Extracts of Swartzia madagascariensis Desv (Fabaceae)

Abstract

This study evaluated the phytochemical and antibacterial properties of the hexane, ethyl acetate and ethanol leaf extracts of Swartzia madagascariensis Desv (Fabaceae). Ethno-medicinally, the leaves are used in the treatment of cutaneous wounds, diarrhoea, malnutrition, inflammations and scabies among others. The phytochemical screening using standard methods, revealed the presence of alkaloids, flavonoids, tannins, cardiac glycosides, saponins, triterpenes and steroids. The antibacterial activities of extracts (2.5, 5, 10, 20 and 40 mg/ml) of S. madagascariensis were tested against three Gram-positive—Staphylococcus aureus, Streptococcus pyogenes, and Corynebacterium ulcerans; one Gram-negative—Escherichia coli pathogens. The activity was determined using well diffusion method with zones of inhibition ranges of 17-18 mm for hexane, 24-27 mm for ethyl acetate and 21-22 mm for ethanol extracts. Minimum Inhibitory Concentration (MIC) of the extracts was determined using 0.5 scale Mc-farland’s turbidity standard. The extracts at 20 mg/ml (hexane), 5-10 mg/ml (ethyl acetate) and10 mg/ml (ethanol) inhibited the growth of the isolates. It also gives Minimum Bactericidal Concentrations ranging from 40 mg/ml (hexane extract), 20 mg/ml (ethyl acetate) and 40 mg/ml (ethanol extract). Zone of inhibitions of extracts were compared to that of standard antibacterial drug, ciprofloxacin (32-37 mm). The results from this study support the traditional use of the leaves of S. madagascariensis in the treatment of bacterial infections.