Abstract: Ten compounds were isolated from Noni (Morinda citrifolia) fermented juice by chromatography methods and identified as esculetin (1),7-hydroxycoumarin (2)、scopoletin (3),6-hydroxy-7-methoxylcoumarin (4),7-hydroxy-4-methylcoumarin (5),1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid (6),(1S,3S)-1-Methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid (7),(1R,3S)-1-Methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid (8),p-hydroxybenzoic acid (9) and gentisic acid (10) by spectroscopic methods.The antioxidative activities were evaluated by DPPH and ABTS^{+ ·} radical scavenging assay.Compounds 1,3,4,10 showed potential antioxidant antivity,in particular,1 and 10 scavenged strongly DPPH and ABTS^+· free radical with IC₅₀ 160.87,8.32 and 6.17,9.71 μmol/L,respectively.Compounds 2 and 5-8 were isolated from Noni for the first time.

Key words: Noni fermented juice, coumarin, organic acid, β-carboline, antioxidative activity