Effects of water extract of 1 : 1 mixture of Phellodendron cortex and Aralia cortex on polyol pathway and oxidative damage in lenses of diabetic rats

Enhanced activity of the polyol pathway and oxidative damage have been impl icated in the pathogenesis of diabetic cataract. We decided to investigate whether these changes in diabetic lenses could be prevented by the water ex tract of Phellodendron cortex and Aralia cortex (P55A), Aldose reductase ac tivity was inhibited significantly by the treatment with P55A. Consequently , it caused a dramatic reduction in the high sorbitol contents observed in the lenses of diabetic rats. In addition, the greatly elevated content of t hiobarbituric acid reactive substances (TBARS) and carbonylated protein in diabetic rats were reduced by P55A treatment. These results suggest that P5 5A extract exerts an antioxidant effect by reducing lipid peroxidation and protein carbonylation res well as having an inhibitory action against aldos e reductase in the lenses of diabetic rats, Copyright (C) 1999 John Wiley & Sons, Ltd.