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A New Prenylated Xanthone from Latex of Garcinia cowa Roxb.

Zhi Na , Qishi Song and Hua b in Hu

Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan, 666303 , P. R. China

Laboratory of Tropical Plant Resource Science, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan, 666303, P. R. China

Abstract: A new prenylated xanthone, 1,6-dihydroxy-3,7-dimethoxy-2-(3,7-dimethyloct-2,6-dienyl) xanthone (3-O-methylcowaxanthone) (1), together with four known xanthones, cowaxanthone (2), 7-O-methylgarcinone (3), α-mangostin (4) and γ-mangostin (5) were isolated from the latex of Garcinia cowa. The structure of compound 1 was elucidated on the basis of spectroscopic data interpretation, including 1D and 2D NMR and HREIMS. The cytotoxic activitiy of 1 against five human cancer cell lines, HL-60, SMMC-7721, A-549, MCF-7 and SW480, was evaluated, but it was inactive (IC 50>40μM).

Keywords: Garcinia cowa Roxb . ; Guttifer ae; prenylated xanthone; 3-O-methylcowaxanthone .