Antibacterial activity assessment of different crude extracts obtained from the leaves of Caesalpinia decapitala grown in Rwanda

Abstract

In this study, both crude extracts and essential oils extracted from Ceasalpinia decapitala leaves have been chemically analysed and their biological activity evaluated. Phyto-chemical screening showed that leaves of this plant contain flavonoids, saponins, tannins and terpenoids. Coupled gas chromatography/mass spectroscopy (GC/MS) analysis indicated that essential oil of this plant was rich in both α and β-pinene (25.5 and 8.4%)), α-phellandrene (4.5%), β-ocymene (31.6%), caryphyllene (7.5%) and geraniol (5.9%). The evaluation of antibacterial activity of different organic crude extracts, against the growth of Escherichia coli, Salmonella typhimurium, Listeria innocua and Staphylococcus aureus showed that only methanol crude extract is active against the growth of Staphylococcus aureus and Salmonella thyphimurium. After further analysis of this active extract, it was found that tannins could be responsible of this antibacterial activity. All bacteria tested in this study were sensible to essential oil extracted from Ceasalpinia decapitala leaves.

Keywords: Antibacterial activity, Caesalpinia decapitala leaves, crude organic extracts, essential oil

Rwanda Journal, Volume 24 Series E 2011