[Coumarins from branch of Fraxinus sieboldiana and their antioxidative activity].

OBJECTIVE

To investigate the chemical constituents from the branch of Fraxinus sieboldiana, and evaluate their antioxidative activity.

METHODS

The chemical constituents were isolated and purified by chromatographic techniques over silica gel, macroporous adsorbent resin, Sephadex LH-20, and preparative HPLC. Structures of the compounds were identified by spectroscopic methods. The antioxidant activity was evaluated by Fe(+2)-cystine induced rat liver microsomal lipid peroxidation.

RESULTS

Eight coumarins were obtained and their structures were elucidated as esculin (1) , esculetin (2), fraxin (3), fraxetin (4), 6, 7-di-O-beta-D-glucopyranosylesculetin (5), scopoletin (6), cleomiscosin D (7) and cleomiscosin B (8). At a concentration of 10(-6) mol x L(-1), compound 4 showed antioxidative activity inhibiting Fe(+2)-cystine induced rat liver microsomal lipid peroxidation with inhibitory rate of 60%.

CONCLUSIONS

Compounds 5, 7 and 8 were obtained from the genus Fraxinus for the first time. Compound 4 showed remarkable antioxidative activity, which was higher than that of VE (35%).