Isolation and Identification of 6-Methylapigenin, a Competitive Ligand for the Brain GABA_A Receptors, from Valeriana wallichii

Abstract

Using the guidance by a competitive assay for the benzodiazepine binding site in the GABA_A receptor, active compounds were isolated from the rhizomes and roots of Valeriana wallichii DC. The UV, NMR and mass spectral data permitted the identification of 6-methylapigenin. This flavonoid has a Ki = 495 nM for the BDZ-bs and a GABA ratio of 1.6 - 2.0, which suggests possible agonistic properties. The calculated percentage of 6-methylapigenin in the crude drug is in the range: 0.013 % to 0.0013 %.

Abbreviations

BDZ-bs:benzodiazepine binding site

GABA ratio:gamma amino butyric acid ratio

GABA_A:gamma amino butyric acid type A receptor

³H-FNZ:tritium flunitrazepam

Ki:inhibition constant

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