Preventive effects of North American ginseng (Panax quinquefolius) on diabetic retinopathy and cardiomyopathy.

Ginseng (Araliaceae) has multiple pharmacological actions because of its diverse phytochemical constituents. The aims of the present study are to evaluate the preventive effects of North American ginseng on diabetic retinopathy and cardiomyopathy and to delineate the underlying mechanisms of such effects. Models of both type 1 (C57BL/6 mice with streptozotocin-induced diabetes) and type 2 diabetes (db/db mice) and age-matched and sex-matched controls were examined. Alcoholic ginseng root (200 mg/kg body weight, daily oral gavage) extract was administered to groups of both type 1 and type 2 diabetic mice for 2 or 4 months. Dysmetabolic state in the diabetic mice was significantly improved by ginseng treatment. In both the heart and retina of diabetic animals, ginseng treatment significantly prevented oxidative stress and diabetes-induced upregulations of extracellular matrix proteins and vasoactive factors. Ginseng treatment in the diabetic animals resulted in enhancement of stroke volume, ejection fraction, cardiac output, and left ventricle pressure during systole and diastole and diminution of stroke work. In addition, mRNA expressions of atrial natriuretic factor and brain natriuretic factor (molecular markers for cardiac hypertrophy) were significantly diminished in ginseng-treated diabetic mice. These data indicate that North American ginseng prevents the diabetes-induced retinal and cardiac biochemical and functional changes probably through inhibition of oxidative stress.