Isolation and structure determination of cypritibetquinone A and B, two new phenanthraquinones from Cypripedium tibeticum.

OBJECTIVE

To study the chemical constituents of Cypripedium tibeticum.

METHODS

Compounds were isolated by repeated silica gel chromatography and purified on Sephadex LH-20 and structures were determined by spectral analysis.

RESULTS

Cypritibetquinones A and B were isolated from the ethyl acetate residue and their structures were determined as 7-hydroxy-2-methoxy-1 4-phenanthraquinone (1) and 7-hydroxy-2, 10-dimethoxy-l1 4-phenanthraquinone (2), respectively, by extensive spectral analyses.

CONCLUSIONS

Cypritibetquinones A and B are two new phenanthraquinones.