The antioxidant effect of carnosol in bovine aortic endothelial cells is mainly mediated via estrogen receptor α pathway.

Antioxidant action is critical for maintaining the normal cardiovascular function and vascular endothelial cell is an important target of estrogen action through estrogen receptor (ER) pathway. This study is carried out to explore the antioxidant effect of carnosol in bovine aortic endothelial cells (BAECs) via ER pathway. The ER subtype specific estrogenic effect of carnosol was further demonstrated by luciferase reporter gene assay in human embryonic kidney (HEK) 293 cells. Carnosol was extracted from Chinese medicine Rosmarinus officinalis. ER positive BAECs were employed in cell proliferation assay and cell apoptosis tests. Oxidative stress by intracellular reactive oxygen species (ROS) were measured via 2'7'-dichlorofluorescein (DCF) production. ERα and ERß specific antagonists 1,3-bis(4-hydroxyphenyl)-4-methyl-5-[4-(2-piperidinylethoxy)phenol]-1H-pyrazole (MPP) and 4-[2-phenyl-5,7-bis(trifluoromethyl)pyrazolo[1,5-a]pyrimidine-3-yl]phenol (PHTPP) were employed as tools in the experiment. ER negative HEK 293 cells were employed in luciferase reporter gene assay. The results indicate that carnosol can effectively attenuate H(2)O(2) induced slowing down of cell growth and increasing of cell apoptosis. At the meantime, carnosol pretreating can also effectively reduce the H(2)O(2) induced intracellular ROS elevation in BAECs. ERα and ERß antagonist, especially ERα antagonist, can effectively decrease the above antioxidant effects of carnosol. The reporter gene analysis further demonstrates that the action of carnosol on inducing ERE dependent luciferase expression is realized via ER pathway. The conclusion is that carnosol can exert antioxidant effects towards oxidative stress induced by H(2)O(2) in BAECs. And such effects are realized via ER, especially ERα pathway. The results contribute to explain the mechanism of cardiovascular protective function of carnosol in postmenopausal women.

Antidiabetic effects of Tangnaikang on obese Zucker rats and the mechanism.

OBJECTIVE: To observe the effects of Tangnaikang (TNK), a compound traditional Chinese herbal medicine, on glucose metabolism and insulin resistance in obese Zucker rats. METHODS: Twelve male obese Zucker rats, 6 weeks old, were randomly divided into control group and TNK group (3.24 g/kg) after being fed for 2 weeks. All rats received high-fat diet and 4-week treatment. Body weight and blood glucose were tested every week. Oral glucose tolerance test (OGTT) was performed and fasting insulin level was tested on days 0, 14 and 28. Triglyceride, cholesterol, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and free fatty acids (FFA) were tested on day 28. Glucose infusion rate (GIR) was tested by hyperinsulinemic-euglycemic clamp from day 29. The protein expressions of protein kinase B (Akt), phospho-Akt (p-Akt) (Thr308) and glucose transporter protein 4 (GLUT4) in skeletal muscle and GLUT4 in adipose tissue were measured after hyperinsulinemic-euglycemic clamp test. RESULTS: Compared with the control group, the fed blood glucose level and glucose level of OGTT at 120 min had a significant decline in TNK group on day 28, and TNK caused no alteration of the fasting serum insulin, and the GIR increased significantly in hyperinsulinemic-euglycemic clamp study. Furthermore, TNK increased Akt and p-Akt (Thr308) protein expressions in skeletal muscle and decreased the protein expression of GLUT4 in white adipose tissue. Body weight, and triglyceride, cholesterol, LDL-C and FFA contents were slightly decreased in the TNK group, but there were no statistically significant effects. CONCLUSION: TNK increases the protein expressions of Akt and p-Akt (Thr308) of the signal transduction pathway to influence the translocation of GLUT4 in skeletal muscle and improves glucose metabolism by reducing insulin resistance.