The Hypolipidemic Effect of Active Components in the Decoction of Alisma Orientale and their Chemical Structures Characterized by LC-QTOF-MS/MS

Background: The decoction of Alisma orientate is used as a traditional medicine for the treatment of hyperlipidemia in China with a long clinical history. The present study undertook a detailed investigation to compare the hypolipidemic effect and chemical composition of two extracts of Alisma orientate prepared by boiling water and organic reagent, respectively. Methods: The hyperlipidemic mice were induced by administration of a High-Fat Diet (HFD) for one month. The body weight of mice and the serum Cholesterol (TC), high-density lipoprotein cholesterol HDL-C), Superoxide Dismutase (SOD), malondialdehyde (MDA), aspartate Aminotransferase (AST) and alanine aminotransferase (ALT) levels were determined. Meanwhile, the chemical constituents of the extracts were characterized using liquid chromatography-quadrupole time of flight mass spectrometry (LC-QTOF-MS/MS). Results: The better hypolipidemic effect was observed in mice administered with the decoction compared to that of methanol extract. In addition, the liver protective effects were confirmed by the photo-graphs stained with oil red lipid stain. As for the chemical constituents in the extracts, twenty major components were identified or characterized using LC-QTOF-MS/MS. Among them, eight oligopeptides were characterized for the first time and proved to only exist in the decoction of Alisma orientate. Conclusions: It is reasonable to assume that the oligopeptides may partially contribute to the hypolipidemic effect of Alisma orientate. The structural characterization procedures also provide a suitable method to analyze oligopeptide analogues in plant samples.