Patent ID: 9206152
Filing Date: 2015-12-08
Classification: C07D

Abstract:
1. A method for extracting dihydroquercetin from roots of larch trees, comprising steps of: {circle around (1)} raw material selection: content of dihydroquercetin in the roots of larch trees selected falls between 2.9%-3.9%; {circle around (2)} raw material cleaning and washing: cutting off the roots of the larch trees selected, removing root hair, washing off dirt and sand with a high-pressure water jet, then air-drying the roots, and storing a same away from light in a relative humidity of 65%; {circle around (3)} raw material processing: crumbling the raw material stored in step {circle around (2)} into wood pieces with a particle size of 3×3×6 mm and a specific surface area of approximately 16, wherein fibers are in a torn state; {circle around (4)} extraction and concentration: using a thermal reflux percolation method to add the wood pieces processed in step {circle around (3)} into an extracting tank and add a mixed solvent consisting of deionized water and acetonitrile at a volume ratio of 1:1, wherein the wood pieces and the mixed solvent have a weight ratio of 1:10, and extracting temperature is 60° C., using a single-effect external circulation evaporator for concentration, wherein the process should be completed within six hours, collecting extracts when the specific gravity of the extracts is 1.04-1.05; {circle around (5)} hydrolyzation: adding the extracts obtained in step {circle around (4)} into a hydrolyzation tank filled with water three times the weight thereof, then adding hydrochloric acid and stirring the mixture, heating a same when pH value is equal to 6, stirring the mixture for 45 minutes at a constant temperature of 75° C., then cooling down a same to the temperature of 30° C., and standing for 2 hours; {circle around (6)} further extraction: adding the hydrolysate of step {circle around (5)} into the extraction tank, then adding an extractant consisting of methyl tert-butyl ether and dioxane at a volume ratio of 3:1, wherein the hydrolysate and the extractant have a weight ratio of 1:0.35-0.4, heating while stirring the mixture, further stirring a same for 30 minutes at a constant temperature of 30° C., then following a cooling process, and standing for 1 hour at a temperature of 22° C., then collecting the supernatant; {circle around (7)} concentration: vacuum sucking the supernatant obtained in step {circle around (6)} into the single-effect external circulation evaporator for concentration, removing the extractant under an atmospheric pressure and at a temperature of 45° C., collecting the sample in a form of powder after the extractant is completely removed; {circle around (8)} recrystallization: adding the powders into a crystallization tank, then adding purified water, wherein the powders and the purified water have a weight ratio of 1:10, heating and stirring the mixture, further stirring a same for 20 minutes at a constant temperature of 75° C., following a cooling process after stopping stirring, standing for 12 hours at a constant temperature of 4° C., collecting the crystals in a tray and delivering a same to a vacuum oven; and {circle around (9)} drying: obtaining dihydroquercetin after a 12-hour drying process at a temperature of 65° C. and a vacuum degree of 0.08 MPa.