ABSTRACT
Objective: To investigate the chemical constituents from Isodon amethystoides distributed in Libo. Methods: Chemical constituents were isolated and purified by chromatography with silica gel, MCI gel CHP 20P, and Sephadex LH-20. The structures of all compounds were elucidated by physicochemical properties, comprehensive spectral data and references. Results: Eighteen known compounds were isolated from the methanol extract of I. amethystoides, which were elucidated as lophanic acid (1), rubesanolide D (2), fladin A (3), 3,4-secoisopimara-4(18),7,15-triene-3-oic acid methylester (4), 3,4-secoisopimara-4(18),7, 15-triene-3-oic acid (5), isopimara-7,15-dien-3-one (6), isopimara-7,15-dien-3β-ol (7), alpiniol (8), (-)-clovane-2,9-diol (9), ursolic acid (10), oleanolic acid (11), epimaslinic acid (12), 7α-hydroxysitosterol (13), β-sitosterol (14), stigmasterol (15), sesamin (16), paulownin acetate (17) and dibutyl phthalate (18). Conclusion: Compound 4 is a new natural product, and compounds 2-9, 15-18 are isolated from I. amethystoides for the first time.