Chemical study of the Chinese medicine Pi Han Yao.

The aim of the present study was to ivnestigate the chemical constituents of the Chinese medicine Pi Han Yao (Gueldenstaedtia delavayi Franch) decoction. Following this, the quantitative determination of the formononetin and maackiain content in Pi Han Yao was established. The chemical constituents were isolated by column chromatography and their structures were elucidated by analysis of spectrometric data and chemical evidence. High-performance liquid chromatography (HPLC) was used for the determination of the formononetin and maackiain content in Pi Han Yao. Seven flavanones were isolated from the Pi Han Yao decoction. Five of the chemical structures were elucidated as 1, 7,2'-dihydroxy-4'-methoxy-isoflavanol; 2, maackiain; 3, formononetin-7-O-β-D-glucoside; 4, formononetin; and 5, 9-(β-D-ribofuranosyl)-adenosine. The other two compounds and their structures require further study. Additionally, the linear range of formononetin and maackiain were 0.03992-0.3992 and 0.0292-0.292 µg, and their recoveries were 100.31 and 100.44%. To the best of our knowledge, compounds 1-5 were obtained from Pi Han Yao for the first time. The HPLC method use for determination of formononetin and maackiain in Pi Han Yao was simple, accurate and reliable. Findings from the present study suggest that these methods may be used to evaluate the quality of Pi Han Yao and provide an experience basis for quality standards of this medicinal material.