Screening of eight alkaloids and ten flavonoids isolated from four species of the genus Boronia (Rutaceae) for antimicrobial activities against seventeen clinical microbial strains

Eight alkaloids and ten flavonoids isolated from four species of Boronia of the Rutaceae were screened against 17 clinical microbial strains. Of the test compounds, three acridone and one quinolone alkaloids and eight flavonoids were reported as novel natural products. Screening was carried out by the standard disc diffusion method. Of the tested compounds, six alkaloids and seven flavonoids including the novel products were active against six clinical strains. The active compounds showed mild to moderate activities against Bacillus subtilis, Staphylococcus aureus, Sarcina lutea, exterotoxigenic Escherichia coli, Salmonella typhi and Klebsiella sp. Of the active flavonoids, some exhibited fairly significant activity towards Staphylococcus aureus, Sarcina lutea, Salmonella typhi and Klebsiella sp. The flavonoids were observed to have higher spectrum and magnitude of activity than those of the alkaloids. A standard ampicillin disc was used to compare the results. Copyright (C) 2002 John Wiley Sons, Ltd.