Essential oil composition of Curcuma species and drugs from Asia analyzed by headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry

Essential oils (EOs) comprised of various bioactive compounds have been widely detected in the Curcuma species. Due to the widespread distribution and misidentification of Curcuma species and differences in processing methods, inconsistent reports on major compounds in rhizomes of the same species from different geographical regions are not uncommon. This inconsistency leads to confusion and inaccuracy in compound detection of each species and also hinders comparative study based on EO compositions. The present study aimed to characterize EO compositions of 12 Curcuma species, as well as to detect the compositional variation among different species, and between the plant specimens and their related genetically validated crude drug samples using headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry. The plant specimens of the same species showed similar EO patterns, regardless of introducing from different geographical sources. Based on the similarity of EO compositions, all the specimens and samples were separated into eight main groups: C. longa; C. phaeocaulis, C. aeruginosa and C. zedoaria; C. zanthorrhiza; C. aromatica and C. wenyujin; C. kwangsiensis; C. amada and C. mangga; C. petiolata; C. comosa. From EOs of all the specimens and samples, 54 major compounds were identified, and the eight groups were chemically characterized. Most of the major compounds detected in plant specimens were also observed in crude drug samples, although a few compounds converted or degraded due to processing procedures or over time. Orthogonal partial least squares-discriminant analysis allowed the marker compounds to discriminate each group or each species to be identified.