IDENTIFICATION OF AN ACTIVE PRINCIPLE IN ESSENTIAL OILS AND HEXANE-SOLUBLE FRACTIONS OF CURCUMA-XANTHORRHIZA ROXB SHOWING TRIGLYCERIDE-LOWERING ACTION IN RATS

Curcuma xanthorrhiza Roxb. (C. xanthorrhiza), known as temu lawak or J avanese turmeric, has been traditionally used in Indonesia for food an d medicinal purposes. As little attention has been focused on the role of C. xanthorrhiza in lipid metabolism, the hypotriglyceridaemic acti vity and the active principles of the essential oil and hexane-soluble fractions prepared from C. xanthorrhiza were investigated in rats. Th e major component (approx. 65%) of the essential oil was identified as alpha-curcumene by capillary gas chromatography/mass spectrometry. Ad dition of essential oils (0.02%), prepared by steam distillation, to a purified diet resulted in a lower hepatic triglyceride concentration without influencing the serum triglyceride, whereas addition of the he xane-soluble fraction (0.5%) resulted in a lower concentration of seru m as well as liver triglycerides. Rats fed the essential oil and hexan e-soluble fraction had lower hepatic fatty acid synthase activity. The fraction containing alpha-curcumene, prepared from the hexane-soluble fraction by silica gel column chromatography, suppressed the synthesi s of fatty acids from C-14acetate in primary cultured rat hepatocyte s. Thus, alpha-curcumene is one of the active principles exerting trig lyceride-lowering activity in C. xanthorrhiza.