Inhibition of human low density lipoprotein and high density lipoprotein oxidation by oligostilbenes from rhubarb

Abstract

The objective of the present study was to elucidate the beneficial properties of ampelopsine B (1) and ε-Viniferin (2), two oligostilbenes isolated from rhubarb, toward cardiovascular disease by protecting human lipoproteins against lipid peroxidation. In low density lipoprotein (LDL) oxidation, both 1 and 2 exert an inhibitory activity against Cu2+-, 2,2′-azobis-(2-amidinopropane) hydrochloride (AAPH)-induced, as exhibited by prolongation of lag time from 52 to 118 and 136 min, respectively, and also increasing the lag time 38 to 105 and 128 min in high density lipoprotein (HDL) oxidation for 1 and 2, respectively, at the concentration of 3.0 μM. In generation of thiobarbituric acid reactive subtances (TBARS), compounds 1 and 2 inhibited LDL oxidation mediated by either catalytic Cu2+ or thermo-labile radical initiator (AAPH) in a dose-dependent manner with IC 50 values of 3.6 and 6.0 μM for 1, and 1.7 and 3.2 μM for 2, respectively. In addition, compounds 1-2 also showed strong ability to protect HDL oxidation induced by both Cu2+ and AAPH with low IC50 values. The results suggest that oligostilbenes 1-2 may have a role in preventing lipoprotein oxidation. © 2008 Pharmaceutical Society of Japan.