Abstract: Ethanol extract of lotus leaves was first obtained, and the extract wa s then purified using chloroform. The effects of several factors on inhibitory a ctivity are studied. An inhibitory mechanism of the lotus leaf derived lipase i nhibitor is proposed. This inhibitor does not act directly on the lipase molecul e but blocks the enzyme substrate contact by modifying the emulsion of the lipi d substrate. The inhibitory constant ( K i) is 0.2 mg/mL. Based on Dixon plo ts and Linweaver Burk plots, the lipase inhibitor demonstrates uncompetitive inhibiti on for lipase.

Key words: alkaloid, lipase, lotus leaf