Antimicrobial activity of the dichloromethane extract from in vitro cultured roots of Morinda royoc and its main constituents.

The dichloromethane extract and seven anthraquinones isolated from in vitro cultured roots of Morinda royoc L. were tested for their antimicrobial activity against seven yeast and seven bacterial strains. The extract showed a minimum inhibitory concentration (MIC) value of 15.6 microg/m against all species of Candida tested; except C. glabrata (MIC 1.95 microg/mL), and it inhibited the growth of oxacillin-resistant Staphylococcus aureus (MIC 31.2 microg/mL). Only morindone showed activity against all yeast strains (MIC 1.9 microg/mL), and against oxacillin-resistant Staphylococcus aureus (MIC 15 microg/mL).