Isolation of a Major Antimicrobial Compound from Stem Bark of Glossonema boveanum (Decne)

Medicinal plants have been used as traditional remedies for the treatments of different ailments, and large number of human population still depends on these medicinal plants for their preventive and curative properties Glossonema boveanum is a medicinal plant widely used in a folk medicine in both West and North Africa. Column chromatography of the ethyl acetate extract from stem bark of Glossonema boveanum yielded one pentacyclic triterpenoid (betulinic acid) which is reported for the first time in this plant. The structure of the isolated compound was identified on the basis of 1D NMR (1H, 13C and DEPT), 2D NMR (COSY, HSQC, HMBC and NOESY) and by comparison with reported data. The compound was then tested for its antibacterial activity against two Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis) and three Gram-negative bacteria (Salmonella typhi, Shigella dysenteriae and Escherichia coli) and was found to be effective against the bacteria. The result of the MIC revealed that the lowest concentration of betulinic acid that inhibited the growth of the bacteria was 3.125 µg/ml for S. aureus and S. dysenteriae. This study concluded that the stem bark of G. boveanum, used traditionally as a medicinal plant for the treatment of typhoid fever, bacillary dysentery, diarrhoea and stomach pain has antibacterial activities against the causative bacteria.