Novel bioactivities of Curcuma longa constituents.

Bioassay-directed fractionation of ethyl acetate extract from Curcuma longa Linn. rhizomes yielded three curcuminoids, which displayed topoisomerase I and II enzyme inhibition activity. Curcumin III (3) was the most active curcuminoid, inhibiting topoisomerase at 25 micrograms mL-1. Curcumin I (1) and curcumin II (2) inhibited the topoisomerases at 50 micrograms mL-1. Fractionation of the volatile oil from the rhizomes afforded ar-turmerone (4), which displayed mosquitocidal activity with an LD100 of 50 micrograms mL-1 on Aedes aegyptii larvae. Bioassay-directed fractionation of hexane extract from the turmeric leaves yielded labda-8(17),12-diene-15,16 dial (5) with antifungal activity against Candida albicans at 1 micrograms mL-1 and inhibited the growth of Candida kruseii and Candida parapsilosis at 25 micrograms mL-1. In addition, 5 displayed 100% mosquitocidal activity on A. aegyptii larvae at 10 micrograms mL-1.