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 orientale 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 orientale 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 photographs 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 orientale. Conclusions: It is reasonable to assume that the oligopeptides may partially contribute to the hypolipidemic effect of Alisma orientale. The structural characterization procedures also provide a suitable method to analyze oligopeptide analogues in plant samples.