Inhibitory effects of an aqueous extract of Apocynum venetum leaves and its constituents on Cu2+-induced oxidative modification of low density lipoprotein

An aqueous extract of Apocynum venetum leaves and its constituents inhibite d thiobarbituric acid reactive substances (TBARS) and conjugated-diene form ation in the Cu2+-induced oxidation of low density lipoprotein (LDL) in vit ro, The TEARS formation was most strongly inhibited by chlorogenic acid wit h an IC50 value of 1.9 muM, but other constituents were in a range of 2.3-2 3.3 muM. On the other hand, the lag time in the conjugated-diene formation was dose- dependently prolonged by addition of the aqueous extract, Catechin prolonge d the lag time more than 300 min and other constituents such as chlorogenic acid, epicatechin, epigallocatechin, hyperoside and isoquercitrin led to n o conjugated-diene formation within 700 min under the experimental conditio ns, Copyright (C) 2000 John Wiley & Sons, Ltd.