The effect of trans-resveratrol and pterostilbene on lipid peroxidation in human erythrocytes in vitro.
|Krzysztof Soboń , Renata Mikstacka , Wanda Baer-Dubowska|
Poznan University of Medical Sciences, Department of Pharmaceutical Biochemistry, ul. Swiecickiego 4, Poznań 60-781, Poland
Reactive oxygen species (ROS) induce oxidative stress and damage to cellular macromolecules. Free radical-induced peroxidation of membrane lipids and oxidative damage of DNA are considered to be associated with a wide variety of health problems, such as cancer, atherosclerosis and aging. Antioxidative action of phytochemicals seems to be of great importance in cancer chemoprevention, especially at the initiation and promotion stage.
trans-Resveratrol (3,5,4’-trans-trihydroxystilbene) is a natural phytoalexin, which occurs in mullberries, peanuts, skin of grapes and red wine. Its dimethyl ether, pterostilbene (3,5-dimethoxy-4'-hydroxystilbene) is present in human diet mainly as a component of grapes and blueberries. Chemopreventive action of resveratrol has been already established at numerous experimental models. Recently, it was reported that pterostilbene exhibits the cancer chemopreventive activity comparable to that of trans-resveratrol. Furthermore, pterostilbene was shown to have hypoglycemic activity and to be effective as a lipid/lipoprotein lowering agent. Both stilbene derivatives exhibit significant antioxidative properties. Pterostilbene was found to have activity comparable to that of resveratrol in DPPH radical scavenging assay. Both compounds were more effective than Trolox (a reference inhibitor) as free radical scavengers of ABAP-derived peroxyl radicals. In our studies the effect of resveratrol and pterostilbene on lipid peroxidation was determined in human red blood cells in vitro. Peripheral blood was obtained from healthy volunteer blood donors. Erythrocytes were centrifuged, washed three times with 0.9% NaCl and twice with phosphate-buffered saline, pH 7.4, and preincubated with continuous mixing for 2 h. The lipid peroxidation was initiated by 10 mM hydrogen peroxide; while simultaneously catalase activity was inhibited by sodium azide (2 mM). After 1 h incubation with studied compounds, the lipid peroxidation was estimated by spectrophotometric method. The absorbance of TBARS (thiobarbituric acid reactive substances) was measured at 532 nm. The effects of resveratrol and pterostilbene were examined in the range of concentrations from 2,5 µM to 100 µM. Both stilbene derivatives influenced H2O2 - induced lipid peroxidation in human erythrocytes. However, resveratrol inhibited the process of oxidation at higher concentrations (EC 50 > 100 µM); while at the lower concentrations (up to 10 µM) stimulating effect was observed. Pterostilbene effectively inhibited TBARS formation in the studied concentration range with EC 50 equal to 35 ± 4 µM.
The results of this study confirm our previous observations that resveratrol analogues might be more effective as modulators of some biochemical processes than the parent compound. Beneficial activity of pterostilbene seems to be worth further investigations.
Presentation: Poster at Zjazd Polskiego Towarzystwa Biochemicznego, Sympozjum M, by Krzysztof Soboń
See On-line Journal of Zjazd Polskiego Towarzystwa Biochemicznego
Submitted: 2007-04-27 11:30 Revised: 2009-06-07 00:44