Studies On Extraction And Activity Of Dihydroquercetin From Larch

In this study, we extracted dihydroquercetin from larch, optimized the extraction process and aimed to find a new purified material. The activity of dihydroquercetin was studied through the experiment of antioxidant activity in vitro.The experiment investigated the effects of extraction solvent, extraction method, mesh material, extraction temperature, time and solid-liquid ration on the extraction rate of dihydroquercetin, and conducted the orthogonal experiment using temperature, time and solid-liquid ratio as three single factors. Ultimately, the results determined the optimum extraction condition:3times of heat reflux extraction with water at90℃for40minutes with the solid-liquid ration of1:12. Tested with HPLC, the dihydroquercetin extraction rate could get up to85%at the optimum condition.The experiment explored the effects of activated carbon adsorption, ethanol precipitation, macroporous resin adsorption, and polyamide resin adsorption on the purification of dihydroquercetin crude extract. The results suggested that activated carbon adsorption was not suitable for the purification of dihydroquercetin, while the polyamide resin adsorption was the best purification method. Furthermore, the combination of ethanol precipitaion and macroporous resin could be used as a new method for purification of dihydroquercetin. The results of this study revealed that optimum condition of purification could be summarized as follows:concentrate extraction to liquid ratio1:2, add95%ethanol under the mixing state until final concentration of70%, stay in refrigerator at4℃for3hours, centrifuge for15minutes under4000r/min. Then, solution absorbed by H103resin for12hours, desorbed for4hours by60%80mL/g ethanol. The retention rate of dihydroquercetin could be97.8%.In addition, antioxidant activity of the dihydroquercetin compared with L-ascorbic acid in vitro. The results showed that the effect of dihydroquercetin was weaker than L-ascorbic acid in the reducing power, the DPPH radical scavenging ability, and especially in the-OH radical scavenging ability. However, dihydroquercetin was slightly stronger than L-ascorbic acid in the ABTS radical scavenging capacity, and was significantly effective than L-ascorbic acid in inhibiting erythrocyte hemolysis.Macroporous resin was used in purification of dihydroquercetin, and obtained good results. This method may broaden the way of dihydroquercetin purification. The results of the antioxidant activity experiment showed that the dihydroquercetin had a better protective effect for the red blood cells, and was able to prevent the oxidative hemolysis. Therefore, dihydroquercetin revealed a better antioxidant capacity in reducing oxidative damage of capillaries.