Essential oil components in the seed masses of Amomum xanthioides and its related species from Southeast Asia and China.

Previously, to develop an objective identification method for Amomi Semen (AS), the nucleotide sequences of nrDNA ITS region and two cpDNA regions of nine Amomum taxa specimens from Southeast Asia and China were determined, and the generated phylogenetic tree showed six taxa specimens were divided into four groups. In this study, 51 crude drug samples of AS in Japanese markets were classified into four groups or species based on their ITS sequences. Approximately 67% of samples were derived from A. villosum var. xanthioides or A. xanthioides, A. villosum var. villosum and A. longiligulare prescribed in Japanese Pharmacopoeia, and the rest were mixed with A. uliginosum and A. microcarpum. Subsequently, the essential oil compositions of Amomum taxa specimens and AS samples were determined by GC-MS to characterize each group or species. Group 1(A. xanthioides) samples were characterized by containing higher amount of camphor(6) than bornyl acetate(9), and a specific germacrene D-4-ol; group 2(Chinese A. villosum var. villosum and var. xanthioides) by containing higher amount of 9 than 6, a specific isobornyl acetate; group 3(Laotian A. villosum var. villosum and A. longiligulare) by containing higher amount of 6 than 9, and a characteristic neointermedeol, except for A. longiligulare specimen from Hainan, China; group 4(A. uliginosum) by containing equivalent amount of 6 and 9, and the specific (E,E)-farnesyl acetate and (E,E)-farnesol. A. microcarpum samples were discriminated from the above groups by absence of 6 and 9, and with higher amount of (E)-nerolidol. There was a good correlation between genetic classification and chemical discrimination.