Schramm A, Ebrahimi SN, Raith M, Zaugg J, Rueda DC, Hering S, Hamburger M. Phytochemical profiling of Curcuma kwangsiensis rhizome extract, and identification of labdane diterpenoids as positive GABAA receptor modulators.
Phytochemistry 2013;
96:318-329. [PMID:
24011802 DOI:
10.1016/j.phytochem.2013.08.004]
[Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Revised: 07/29/2013] [Accepted: 08/09/2013] [Indexed: 06/02/2023]
Abstract
An ethyl acetate extract of Curcuma kwangsiensis S.G. Lee & C.F. Liang (Zingiberaceae) rhizomes (100 μg/ml) enhanced the GABA-induced chloride current (IGABA) through GABAA receptors of the α1β2γ2S subtype by 79.0±7.0%. Potentiation of IGABA was measured using the two-microelectrode voltage-clamp technique and Xenopus laevis oocytes. HPLC-based activity profiling of the crude extract led to the identification of 11 structurally related labdane diterpenoids, including four new compounds. Structure elucidation was achieved by comprehensive analysis of on-line (LC-PDA-ESI-TOF-MS) and off-line (microprobe 1D and 2D NMR) spectroscopic data. The absolute configuration of the compounds was established by comparison of experimental and calculated ECD spectra. Labdane diterpenes represent a new class of plant secondary metabolites eliciting positive GABAA receptor modulation. The highest efficiency was observed for zerumin A (maximum potentiation of IGABA by 309.4±35.6%, and EC50 of 24.9±8.8 μM).
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