Comparison of raw and processed Radix Polygoni Multiflori (Heshouwu) by high performance liquid chromatography and mass spectrometry

BACKGROUND Radix Polygoni Multiflori is the dried root tuber of Polygonum multiflorum Thunb. (Fam. Polygonaceae). According to Chinese medicine theory, raw (R-RPM) and processed (P-RPM) Radix Polygoni Multiflori possess different properties. The present study investigates the differences in chemistry between raw and processed Radix Polygoni Multiflori. METHODS Five pairs of R-RPM and P-RPM as well as 15 commercial decoction pieces were analyzed with high performance liquid chromatography (HPLC) and mass spectrometry (MS). RESULTS Two anthraquinones, namely emodin-8-O-(6'-O-malonyl)-glucoside and physcion-8-O-(6'-O-malonyl)-glucoside disappeared or decreased significantly and 2,3,5,4'-tetrahydroxystilbene-2-O-beta-D-glucopyranoside, emodin-8-O-beta-D-glucopyranoside and physcion-8-O-beta-D-glucopyranoside decreased after the R-RPM samples being processed. On the other hand, the contents of emodin and physcion generally increased after processing. CONCLUSION The present study indicates that processing Radix Polygoni Multiflori may change the contents and types of chemicals in it. These changes are probably responsible for the various pharmacological effects of R-RPM and P-RPM as well as hepatotoxicity.