Curcuminoid and essential oil components of turmeric at different stages of growth cultivated in Iran

Abstract

Turmeric is an important herb used as medicines,

Turmeric is an important herb used as medicine, condiment and cosmetic. Its main active compounds are curcuminoids and essential oils. The biomass production, essential oil composition and curcuminoid content of Curcuma longa are known to be dependent on the growth and development conditions of rhizome. Iran is a major importer of turmeric in the Middle East. The aim of this work was, therefore, to evaluate the curcuminoids and essential oil composition as well as curcumin content at different stages of growth of C. longa rhizome cultivated in Isfahan. Rhizomes of C. longa were obtained from Thailand and cultivated in University of Isfahan greenhouse. The growth media was 10 cm diameter pots containing perlite and cocoperlite watered using Hoagland nutrient solution. Plants were harvested at different stages of growth and rhizomes’ fresh and dry weights were measured. The curcuminoids and the essential oils were analyzed by TLC and GC-MS, respectively.  a-Phellanderen, terpinolen,  a-zingiberene, b-sequiphellanderen, r-turmerone, and a-turmerone were the main components of essential oils. The curcuminoids were detected as curcumin, desmethoxy curcumin, and bisdesmethoxy curcumin. The turmerone in harvested rhizome accounted for almost 90% of the oil composition. It has been reported that the major compounds found in turmeric oil, up to 50-60%, are the sesquiterpene ketones, ß-, and r-turmerone. The rhizomes of the C. longa cultivated in Iran have similar flavor and color to those of the turmeric rhizome imported to Iran. It seems that Iranian turmeric production can be cured and dried for condiment use.