Protective effect of ginsenosides Rg2 and Rh1 on oxidation-induced impairment of erythrocyte membrane properties

The extract from Panax ginseng has been reported to improve the microcirculation in various organs. However, the mechanisms underlying this phenomenon are still poorly understood. In the present study, using the rheological properties of erythrocytes as an index, we have screened the components of Panax ginseng extract and identified Rg(2) and Rh(1) as the active ingredients. These two ginsenosides prevented the oxidative stress-induced elevation of erythrocyte suspension viscosity and the impairment of erythrocyte elongation in response to shear stress. Rg(2) and Rh(1) ginsenosides did not have antioxidant activity in an aqueous phase and did not inhibit the peroxidation of membrane lipids, either. However, they inhibited the oxidation-induced decrease of SH-groups in band 3 (anion exchanger-1), one of the important structural proteins of the erythrocyte membrane, but not in other structural proteins: bands 1 and 2 (spectrins), band 4.2 or band 5 (actin). These results suggest that ginsenosides Rg(2) and Rh(1) protect the rheological functions of erythrocytes against oxidative stress by preventing the oxidation of SH-groups in band 3 protein.