Four New Stilbenoids from the Lianas of Gnetum montanum f. megalocarpum

Abstract

From the lianas of Gnetum montanum Markgr. f. megalocarpum Markgr., four new stilbenoids, gnetumontanins A - D (1 - 4) were obtained together with 16 known compounds. Gnetumontanin A (1) is the first oligostilbene dimerized from two oxyresveratrol units, gnetumontanin B (2) is a new stilbene trimer oligomerized from two oxyresveratrol and one resveratrol units, gnetumontanin C (3) is a new stilbenoid with a novel skeleton having a δ-lactone moiety and gnetumontanin D (4) is a glucoside of 3. Their structures were determined by means of spectroscopic evidence, especially 2D NMR techniques. Gnetumontanin B showed potent inhibition of TNF-α with an inhibitory ratio of 58.1 % (P < 0.05) at a concentration of 10 ^{- 5} mol L^-1 and the IC₅₀ was 1.49 × 10 ^{- 6} mol L^-1.

Key words

Gnetum montanum f. megalocarpum - Gnetaceae - gnetumontanins A - D - δ-lactone - tumor necrosis factor inhibitory activity

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