Antimicrobial activity of the alkaloidal constituents of the root bark of Eupomatia laurina

From the root bark of Eupomatia laurina were isolated four anti-microbial alkaloids; sampangine (I), eupomatine-1 (II), liriodenine and lanuginosine. The isolated alkaloids, the fraction from which I+II were isolated (EI), the dichloromethane fraction of the root bark (RD) and the ethyl acetate fraction of the stem bark (SE) were screened against 13 Gram(+) and 12 Gram(-) bacteria, a protozoan and nine fungi. All extracts were found to be active against all the bacteria and protozoan. Antifungal activity was demonstrated by EI, RD and SE fractions only. Compound II and fraction EI were found to be far superior to the standard used, both in broadness and level of activity. MIC was performed on EI and was found to be in most cases 0.5 mug while in some case it was 0.1 mug. Broad-spectrum antifungal activity was exhibited by fraction El,(10 mug disc), RD (4 mg disc) and SE (4 mg disc). MIC was done on EI and was 10 mug. The activity of EI, RD and SE was found to be far superior to the standard ketoconozole (20 mg disc) and griseofulvin (25 mg disc).