Beneficial effects of Chinese prescription Kangen-karyu on diabetes associated with hyperlipidemia, advanced glycation endproducts, and oxidative stress in streptozotocin-induced diabetic rats

Abstract

Aim of the study: In the present study, we investigated the effects of Kangen-karyu, a traditional Chinese prescription comprising six herbs, on diabetes. Materials and methods: Kangen-karyu extract (50, 100, or 200 mg/kg body weight) was administered to streptozotocin (STZ)-induced diabetic rats and serum and hepatic biochemical factors, and protein expressions associated with oxidative stress and advanced glycation endproduct (AGE) formation were measured. Results: The oral administration of Kangen-karyu significantly ameliorated hypertriglyceridemia induced by STZ injection, while serum levels of glucose and total cholesterol were mildly affected. Kangen-karyu also markedly reduced the levels of AGEs and malondialdehyde (MDA), a lipid peroxide product used as an indicator of oxidative stress in both serum and hepatic tissue. In addition, Kangen-karyu dose-dependently lowered the expression levels of Nε-(carboxymethyl) lysine, one of the major component of AGEs closely associated with the pathogenesis of diabetes and liver cirrhosis, and receptor for AGEs, as well as the expression levels of nuclear factor-κB, inducible nitric oxide synthase, and cyclooxygenase-2 (COX-2) associated with oxidative stress. Especially, MDA levels in both serum and hepatic tissue and COX-2 expression increased by STZ were recovered by Kangen-karyu (200 mg/kg body weight) to normal levels. Conclusions: Kangen-karyu showed favorable effects on hypertriglycemia, AGE formation, and oxidative stress in STZ-treated rats, suggesting beneficial effects on diabetes, diabetic hepatopathy, and liver diseases such as cirrhosis, as well as cardiovascular and cerebrovascular diseases. ? 2009 Elsevier Ireland Ltd. All rights reserved.