Abstract: A HPLC method was established for the determination of HMG\|CoA reductase inhibitor activity in vitro by measuring the concentration of NADPH in the determination system. The chromatographic conditions were as follows: Symmetry C18 column （5 μm， 4.6 mm×250 mm）; mobile phase: V（K2HPO4\|KH2PO4）:V（methanol）=85∶15; pH 7.2; flow rate: 1 mL·min-1; detection wavelength: 337 nm; sample quantity: 20 μL; column temperature: 25℃. In this condition， the NADPH linear range was 0.6-600 μmol·L-1. The standard addition recovery rate was 94.48%-101.81%， and the relative standard deviation （n=5） was less than 4.49%. The lowest detection limit was 0.01 μmol·L-1. The inhibitor activity of silkworm chrysalis protein peptide HMG\|CoA reductase was measured by the above method， and the inhibition rate was 28.70% at the concentration of 0.5 mg·mL-1.

Key words: hypolipidemic peptide, HMG\, CoA reductase, NADPH, HPLC