Inhibitory Effect of Polyphenols from Arctium lappa Roots on Lipase

In order to demonstrate the inhibitory effect of polyphenols from Arctium lappa roots (ALP) on lipase, the ALP were extracted and enriched. The content of total polyphenol was determined by Folin-Ciocalteu method, and the index components in ALP were determined by high performance liquid chromatography-UV (HPLC-UV) method. The inhibitory effect and type on lipase of ALP and its index components were determined by p-nitrophenyl butyrate (p-NPB) method. Combined inhibitory effect of them were evaluated by equivalent line diagram method and drug combination index (CI). The results showed that the total polyphenol of ALP reached 51.23%, and the contents of the five index components, i.e., neochlorogenic acid, cryptochlorogenic acid, caffeic acid, chlorogenic acid, and isochlorogenic acid A accounted for 12.87%. ALP showed reversible competitive inhibition on lipase with half maximal inhibitory concentration (IC₅₀) value 1.706 mg/mL. The IC₅₀ of neochlorogenic acid, cryptochlorogenic acid, caffeic acid, chlorogenic acid, and isochlorogenic acid A were 0.872, 0.910, 0.280, 0.847, 0.244 mg/mL, respectively. When the concentration ratio of chlorogenic acid and isochlorogenic acid A was 1:2.15, the CI value was 0.549, and when the concentration ratio of caffeic acid to isochlorogenic acid A was 1:0.87, the CI value was 0.282, which indicated synergistic inhibition effect on lipase. This study provides a theoretical basis for exploring the chemical basis of the lipid-lowering effect of Arctium lappa roots and its lipid-lowering mechanism, and layed a foundation for the development of Arctium lappa roots.