Constituents of Dendrobium devonianum and their antioxidant activity

Objective: To study the chemical constituents of Dendrobium devonianum and identify the material basis components of its function,and then provide the basis for development and utilization of D.devonianum.Method: The constituents were separated and purified on the chromatography of silica gel,Sephadex LH-20 and RP-18 silica gel,and then their structures were elucidated based on the spectra data.ABTS method was used to evaluate the free radical scavenging activity of the phenolic compounds among them.Result: Nine compounds were isolated and identified as 2,3,4,9-tetrahydro-1H-pyridoindole-3-carboxylic acid(1),2′-deoxythymidine(2),adenosine(3),N-trans-p-coumaroyl tyramine(4),N-trans-p-feruloyl tyramine(5),3-methoxy-4-hydroxybenzaldehyde(6),4-hydroxybenzaldehyde(7),3,4-dihydroxybenzoic acid methyl ester(8),and 4-hydroxy-3,5-dimethoxybenzoic acid(9).Compound 5 showed good antioxidant activity with IC50 1.61 mmol·L-1,Compound 9 showed weak antioxidant activity with IC50 35.72 mmol·L-1.Conclusion: All these compounds were isolated from D.devonianum for the first time.Among them,compounds 5 and 9 had some antioxidant activity.