A quality evaluation method of lotus leaf based on its lipid lowering components using QAMS and chemometrics

INTRODUCTION: Lotus leaf has long been used as food and medicine in China and is well-known for its lipid-lowering effects. However, there is a lack of a comprehensive quality evaluation for lotus leaf due to the absence of consideration of the correlation between various components and their efficacy. OBJECTIVES: This study aims to find out the key bioactive components that can be used for quality evaluation of lotus leaf on lipid-lowering effect. METHODS: Thirteen compounds were characterized in the lotus leaf using ultra-high- performance liquid chromatography-time-of-fight mass spectrometry (UPLC-Q-TOF-MS). Five alkaloids and four flavonoids were identified according to their lipid-lowering activities reported in literatures. Then, the contents of these nine components were analyzed in 39 batches of lotus leaves growing in different locations using high performance liquid chromatography diode-array detector (HPLC-DAD), and further evaluated by quantitative analysis of multi-components by single marker (QAMS) and chemometrics. The anti-adipogenic activity of lotus leaves were evaluated for their inhibitory effect on the PPARγ expression by luciferase assay. RESULTS: The 39 batches were clustered into two regions, the north and the south, based on the contents of these components. Three alkaloids, nuciferine, N-nornuciferine, and asimilobine, and three flavonoids, astragalin, hyperoside, and trifolioside, were found to serve as the key factors behind the region differences. Their contents were higher in Guangchang County of Jiangxi Province than other habitat locations. Moreover, the luciferase assay combined with chemometrics showed that these components were positively correlated with lipid-lowering activity of lotus leaf. CONCLUSIONS: Three alkaloids and three flavonoids were screened out and could be used as key compounds for quality evaluation of lotus leaf on lipid-lowering effect.