Comparison of the antioxidant effects of equine estrogens, red wine components, vitamin E, and probucol on low-density lipoprotein oxidation in postmenopausal women

Objective: Oxidized low-density lipoprotein (LDL) seems to play an important role in the etiology of atherosclerosis. To further study this, we performed two studies: (1) we determined the ability of 10 estrogen components of the drug, conjugated equine estrogen (CEE), trans-resveratrol (t-resveratrol) and quercetin (red wine components), trolox (vitamin E analog), and probucol (a serum cholesterol-lowering drug) to delay or prevent the oxidation of plasma LDL isolated from untreated postmenopausal women, and (2) we assessed the effect of long-term (>1 year) estrogen replacement therapy and hormone replacement therapy on LDL oxidation by ex vivo methods. Design: For the in vivo study, three groups of postmenopausal women were selected based on whether they were on long-term CEE therapy (group A: 0.625 mg CEE; n = 21), on combination CEE plus progestogen therapy (group B: 0.625 mg CEE + 5.0 mg medroxyprogesterone acetate, 10 days; n = 20), or not on any hormone therapy (group C; n = 37). For the in vitro study, only LDL samples obtained from group C were used. The kinetics of LDL oxidation were measured by continuously monitoring the formation of conjugated dienes followed by determination of the lag time. Results: All compounds tested protected the LDL from oxidative damage. The relative antioxidant potency of estrogen components was generally greater than that of the other compounds. The minimum dose (nmoles) required to double the lag time from...
Source: Menopause - Category: OBGYN Tags: Commemorative Papers Source Type: research