A pentacyclic triterpene from the leaves of Combretum collinum Fresen showing antibacterial properties against Staphylococcus aureus

Leaf extracts of six different plants, many of which are used by traditional healers, were screened for antibacterial activity. These include Adina microcephaha, Combretum aurea, Combretum bracteosam, Combretum collinum, Filicium decipiens and Ficus moraceae. The highest mass of 118 mg was extracted with acetone from F. decipiens and the lowest mass of 18 mg was extracted from F. moraceae. The bioautography showed antibacterial activity of the dichloromethane and acetone extracts of C. collinum subspecies suluense and F. decipiens against Escherichia coli. It also showed antibacterial activity of the acetone extract of C. collinum subspecies suluense against Staphylococcus aureus. Two compounds were isolated from these extracts and characterized. Their minimum inhibitory concentrations were determined. One compound from C. collinum subspecies suluense had MIC value of 0.5689 mg/ml and compound E had 1.479 mg/ml. The chemical structure proposed for the compound was determined by correlation of HNMR and GC-MS data. The chemical structure of the other compound was not proposed.