Kim YS, Kim NH, Lee SW, Lee YM, Jang DS, Kim JS.
Department of Herbal Pharmaceutical Development, Korea Institute of Oriental Medicine, 461-24 Jeonmin-dong, Daejeon 305-811, Republic of Korea.
Advanced glycation end products and transforming growth factor-beta (TGF-beta) have been implicated in the development of diabetic complications such as cataract. The diverse metabolic effects of protocatechualdehyde (PCA, 3, 4-dihydroxybenzaldehyde) include the inhibition of aldose reductase and oxidation, two processes that are involved in the development of complications in diabetic patients. Here, the potential therapeutic effects of PCA in the treatment of diabetic complications were studied by determining this compound's ability to inhibit the formation of advanced glycation end products-bovine serum albumin (BSA) and the expression of receptor for advanced glycation end products and TGF-beta1 in human lens epithelial cells cultured under diabetic conditions. In addition, the ability of PCA to suppress lens opacification in streptozotocin-diabetic rats was analyzed. PCA significantly reduced advanced glycation end products-BSA formation in vitro and was more effective than aminoguanidine. In human lens epithelial cells, PCA significantly inhibited the induction of receptor for advanced glycation end products protein and mRNA expression by the receptor for advanced glycation end products-specific ligand S100b. Moreover, PCA inhibited high glucose- or S100b-induced TGF-beta1 protein and mRNA expression as well as nuclear accumulation of phosphorylated Smad2/3. In streptozotocin-induced diabetic cataract in rats, oral administration of PCA (25 mg/kg body weight) for 8 weeks significantly ameliorated the development of lens opacity (cataract) with effect on glycemic control. These results suggest that PCA is of therapeutic interest with respect to the prevention of diabetic complications such as diabetic cataract.
[Prevention of galactose-induced cataractogenesis in rats by salvianolic acid A]
[Article in Chinese]
Du GH, Qiu Y, Tian YE, Zhang JT.
Institute of Materia Medica, Chinese Academy of Medical Sciences, Beijing.
Salvianolic acid A has been demonstrated to have efficient antioxidative and free radical scavenging effects. In the present experiments, the preventive effects of salvianolic acid A on galactose-induced cataract in rats were investigated. Dropping 0.05% salvianolic acid A in the eyes (two times a day) was found to delay the development of cataract. The contents of MDA and H2O2 in the cataract lens were decreased in salvianolic acid A treated rats. The protein and non-protein thiols in the cataract lens of the salvianolic acid A treated rats were higher than those of control rats. In in vitro experiments salvianolic acid A was shown to inhibit aldose reductase activity. These results indicate that salvianolic acid A can prevent galactose-induced cataract by antioxidation and inhibition of aldose reductase.
Effect of protocatechualdehyde on receptor for advanced glycation end products and TGF-beta1 expression in human lens epithelial cells cultured under diabetic conditions and on lens opacity in streptozotocin-diabetic rats.
Kim YS, Kim NH, Lee SW, Lee YM, Jang DS, Kim JS.
Department of Herbal Pharmaceutical Development, Korea Institute of Oriental Medicine, 461-24 Jeonmin-dong, Daejeon 305-811, Republic of Korea.
Advanced glycation end products and transforming growth factor-beta (TGF-beta) have been implicated in the development of diabetic complications such as cataract. The diverse metabolic effects of protocatechualdehyde (PCA, 3, 4-dihydroxybenzaldehyde) include the inhibition of aldose reductase and oxidation, two processes that are involved in the development of complications in diabetic patients. Here, the potential therapeutic effects of PCA in the treatment of diabetic complications were studied by determining this compound's ability to inhibit the formation of advanced glycation end products-bovine serum albumin (BSA) and the expression of receptor for advanced glycation end products and TGF-beta1 in human lens epithelial cells cultured under diabetic conditions. In addition, the ability of PCA to suppress lens opacification in streptozotocin-diabetic rats was analyzed. PCA significantly reduced advanced glycation end products-BSA formation in vitro and was more effective than aminoguanidine. In human lens epithelial cells, PCA significantly inhibited the induction of receptor for advanced glycation end products protein and mRNA expression by the receptor for advanced glycation end products-specific ligand S100b. Moreover, PCA inhibited high glucose- or S100b-induced TGF-beta1 protein and mRNA expression as well as nuclear accumulation of phosphorylated Smad2/3. In streptozotocin-induced diabetic cataract in rats, oral administration of PCA (25 mg/kg body weight) for 8 weeks significantly ameliorated the development of lens opacity (cataract) with effect on glycemic control. These results suggest that PCA is of therapeutic interest with respect to the prevention of diabetic complications such as diabetic cataract.