Vasorelaxant effects of 50 commonly used traditional herbal prescriptions on isolated rat aortic rings.

OBJECTIVE: To investigate the vasorelaxant activities of 50 common traditional herbal prescriptions (THPs) on isolated rat aortic rings. METHODS: An electric extractor was used to extract THPs. Rat aortic rings were precontracted using phenylephrine in organ chambers containing Krebs-Henseleit solution. Decoctions of THPs were added in increasing concentrations (10-1000 µg/mL) to investigate vasorelaxant activities. The vasorelaxant effects of THPs were calculated as percentage of contraction in response to phenylephrine. RESULTS: Several THPs such as Tianwangbuxin Dan, Banxiaxiexin Tang, and Mahuang Tang, significantly relaxed precontracted aortic rings. In contrast, Xiaochaihu Tang, Shensuyin, and Guizhifuling Wan significantly contracted aortic rings. Furthermore, these THPs increasingly relaxed or contracted aortic rings relaxed by amlodipine. CONCLUSION: Our findings suggest that hypertension can be treated using THPs. However some THPs can counteract treatment of hypertension. Further studies should be developed on use of THPs for treatment of hypertension are critical, and guidelines for use of traditional herbal medicines to treat hypertension.

Natural compounds, fraxin and chemicals structurally related to fraxin protect cells from oxidative stress

Coumarins comprise a group of natural phenolic compounds found in a variety of plant sources. In view of the established low toxicity, relative cheapness, presence in the diet and occurrence in various herbal remedies of coumarins, it appears prudent to evaluate their properties and applications further. The purpose of this study is to investigate cellular protective activity of coumarin compound, fraxin extracted from Weigela florida var. glabbra, under oxidative stress, to identify genes expressed differentially by fraxin and to compare antioxidative effect of fraxin with its structurally related chemicals. Of the coumarins, protective effects of fraxin against cytotoxicity induced by H2O2 were examined in human umbilical vein endothelial cells (HUVECs). Fraxin showed free radical scavenging effect at high concentration (0.5 mM) and cell protective effect against H2O2-mediated oxidative stress. Fraxin recovered viability of HUVECs damaged by H2O2- treatment and reduced the lipid peroxidation and the internal reactive oxygen species level elevated by H2O2 treatment. Differential display reverse transcription-PCR revealed that fraxin upregulated antiapoptotic genes (clusterin and apoptosis inhibitor 5) and tumor suppressor gene (ST13). Based on structural similarity comparing with fraxin, seven chemicals, fraxidin methyl ether (29.4% enhancement of viability), prenyletin (26.4%), methoxsalen (20.8 %), diffratic acid (19.9%), rutoside (19.1%), xanthyletin (18.4%), and kuhlmannin (18.2%), enhanced more potent cell viability in the order in comparison with fraxin, which showed only 9.3% enhancement of cell viability. These results suggest that fraxin and fraxin-related chemicals protect HUVECs from oxidative stress.