Abstract: The aim of this research was to investigate the chemical constituents from Dendrobium heterocarpum Lindl.and antioxidant and anti-inflammatory activities of selected compounds.15 compounds were isolated and purified from Dendrobium heterocarpum Lindl.by silica gel column chromatography,Sephadex LH-20 and semipreparative HPLC.And their structures were identified as 3,4′-dihydroxy-5-methoxybibenzyl (1),batatasin Ⅲ (2),3-hydroxy-4′,5-dimethoxybibenzyl (3),3-O-methylgigantol (4),gigantol (5),3,4-dihydroxy-4′,5-dimethoxybibenzyl (6),moscatilin (7),dendrocandin A (8),(S)-3,4,α-trihydroxy-4′,5-dimethoxybibenzyl (9),densiflorol A (10),dendrocandin I (11),dendrocandin F (12),coelonin (13),carthamidin (14),4-hydroxy-2-methoxy-3,6-dimethylbenzoic acid (15) based on extensive spectroscopic methods1H NMR,13C NMR,HSQC,HMBC).Compounds 1-15 were isolated from Dendrobium heterocarpum for the first time,of which compound 14 were obtained from this genus for the first time.Some isolates were evaluated for the inhibitory activities on nitric oxide production and the ABTS and DPPH radical scavenging activity.Compounds 3,5 and 11 showed inhibitory effect on the NO production in RAW264.7 macrophage cell.And Compounds 5 and 6 showed DPPH and ABTS+ radicals scavenging activity.

Key words: Dendrobium heterocarpum, bibenzyl, carthamidinl, RAW264.7 macrophage cell, DPPH radical