ABSTRACT
Objective: To optimize the purification process of total coumarin from Fraxini Cortex using macroporous resin. Methods: The single factor methods have been used to investigate the choice of type, adsorption performance, and desorption performance and the purification of the total coumarin from Fraxini Cortex by macroporous resin. The adsorption rate, resolution, resolution rate, and transfer rate of the total coumarin from Fraxini Cortex, four kinds of coumarin constituents, such as aesculin, aesculetin, fraxin, and fraxetin were used as examining indexes. Results: The ADS-5 was the most suitable type for the purification of total coumarin from Fraxini Cortex among the seven kinds of macroporous resin. Adsorption parameters: Crude drug-the resin was 0.8 g/g which was the sample amount; The concentration of sample solution was 0.75 g crude drug/mL; The pH value of sample liquid was 4.0-4.3 (liquid sample); The speed of the sample through the resin column was 2-4 BV/h. Elution parameters: The volume of the water cleaning fluid impurities was 1 BV; The elution solvent was 25% ethanol; The elution speed was 2 BV/h; The elution volume was 3 BV. After the purification, the transfer rate of total coumarin from Fraxini Cortex was 74.27%, the transfer rate of four kinds of coumarin was 83.06%, the extract rate of total coumarin was 7.35%, the removal of impurities was 14.00%, among which the content of total coumarin was 54.72%, the contents of the four kinds of components were 36.01%, the total coumarin extraction yield was 4.02%. Conclusion: This method to purify the total coumarin from Fraxini Cortex using ADS-5 can get better purification effect, the purification process is also stable.
ABSTRACT
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.