Intraspecific Chemical Variability of Essential Oil of Curcuma caesia (Black Turmeric)

Abstract

Rhizome essential oil of Curcuma caesia has myriad of therapeutic activities which is being practiced since ages as folklore remedy but commercially remained underutilized till date. Though previous reports had characterized the phytoconstituents of C. caesia essential oil, a comparative assessment will lead to identify a good germplasm for commercialization. Quality germplasm should have high yield and quality constituents. Hence, the current study deals with intraspecific variability of C. caesia rhizome essential oil associated with two geographical regions, i.e., Odisha and West Bengal. The Principal Component Analysis and Agglomerative Hierarchical Clustering analysis distinguished two groups of essential oils on the basis of the phytoconstituents. The highest oil yield was found in Mayurbhanj (0.64 ± 0.015% w/w) population, whereas the lowest oil yield was in South 24-Parganas population (0.39 ± 0.01% w/w). The chemical constituents of C. caesia were analyzed by Gas Chromatography–Mass Spectrometry which detected a total of 34 compounds accounting to 90.08–97.94% of the total oil. Oxygenated monoterpenes constituted the major fraction followed by oxygenated sesquiterpenes. West Bengal accessions were dominated by oxygenated monoterpenes (34.8–45.41%) followed by oxygenated sesquiterpenes (26.63–38.06%). However, Odisha accessions were rich in oxygenated monoterpenes (37.6–54.36%) followed by sesquiterpene hydrocarbons (21.9–33.8%). In this study, phytochemical variability in C. caesia associated with geographical distribution patterns has been successfully studied in respect of essential oil yield and quality.