Variation of bioactive components in Curcuma longa in Thailand

Abstract

Curcuma longa L. (turmeric) is a popular medicinal herb of Thailand as a spice and a colouring agent. Medicinal uses of the rhizome arise from volatile oil as a carminative and for antifungal activity, and yellow curcuminoids for anti-oxidative and anti-inflammatory properties. In Thailand, C. longa is mainly used in forms of capsules/tablets of turmeric powder for herbal medicine, while its extract is popularly used in herbal cosmetics. Thus quality assessment of this plant needs to be controlled for the limits of volatile oil and total curcuminoids contents. This study was undertaken to evaluate the contents of essential oil and total curcuminoids in dried powder of C. longa rhizome collected from 13 locations from North, Northeast, Central and South Thailand during January to April 2005. The highest content (8.20 ± 1.66% v/w) of essential oil was found in samples from the North where the climate is cool, while the lowest oil content (7.00 ± 0.00% v/w) was found in samples from the South where it rains all year. In contrast, the highest total curcuminoids content (8.99 ± 0.83% w/w) was found in the southern samples while the lowest content (4.80 ± 1.83% w/w) was found in the northern samples. The total curcuminoids in all samples was found in the limit of 3.07 ± 0.09 to 9.58 ± 0.20% dry weight. The average of volatile oil content was found to be 7.77 ± 1.20% w/w, while the average of total curcuminoids content was found to be 6.24 ± 1.95% w/w. This information will be useful as a guidance for standardization of C. longa powder and the extracts, and finding sources of good quality of C. longa in Thailand.