In vitro antibacterial activity of alkaloid extract from stem bark of Mahonia manipurensis Takeda

The genus Mahonia belongs to one of the primitive groups of plant family Berberidaceae. A number of species from this genus are widely used in traditional and folk medicine systems in different parts of the world. Mahonia manipurensis crude alkaloid extract was obtained from the stem bark by extracting from 80% of methanol extract. In vitro antibacterial activity of the alkaloid extract was screened against five different pathogenic bacteria of clinical origin including two species of gram-negative and three species of gram-positive bacteria. Using agar well diffusion method, growth inhibition was observed in four of the five tested pathogens at two different concentrations (5 and 2.5 mg/ml). The result indicates that the alkaloid extract exhibited significant antibacterial activity. Similar antimicrobial activity was also reported from other species of this genus by previous workers. Minimum inhibitory concentration (MIC) was also determined using agar dilution method, following two-fold serial dilution and observed that the lowest value was exhibited by Bacillus cereus and Enterococcus faecalis each corresponding to 256 mu g/ml concentration.