Free radical-scavenging activity of Korean red ginseng for erectile dysfunction in non-insulin-dependent diabetes mellitus rats

Objectives. To investigate the antioxidant activity of Korean red ginseng (KRG) and its effect on erectile function in non-insulin-dependent diabetes mellitus (NIDDM) rats. Oxidative stress is an important factor in vascular complications of diabetes. Methods. A total of 84 male Sprague-Dawley rats were included in this study. NIDDM was induced by an intraperitoneal injection of 90 mg/kg of streptozotocin on day 2 after birth. According to the diabetic period, they were classified as either short-term (22 weeks, n = 32) or long-term (38 weeks, n = 32) diabetics. Of those, 20 (10 short-term and 10 long-term) were fed 30 mg/kg of KRG three times weekly for 1 month. The remaining diabetic rats (22 short-term and 22 long-term) and their age-matched controls (n = 10 each for each group) were fed a normal diet. Erectile function was measured after electrostimulation of the cavernous nerve. The total cavernous malondialdehyde and glutathione levels were measured using a spectrophotometric assay. Results. The intracavernous pressure after nerve stimulation and cavernous glutathione level were significantly lower in the long-term than the short-term diabetics with a normal diet and were markedly decreased compared with their age-matched controls (P < 0.01 and P < 0.05, respectively). The malondialdehyde content was markedly increased in the short-term diabetics compared with the controls (P < 0.05). In contrast, erectile function was not impaired in the diabetic group treated with KRG. Furthermore, both glutathione and malondialdehyde levels in those treated with KRG were comparable to their age-matched controls. Conclusions. Oxidative stress to cavernous tissue may be a contributory factor in erectile dysfunction in diabetics. KRG may preserve potency in the NIDDM rats through its antioxidant activity. (c) 2005 Elsevier Inc.