Method for preparing ursolic acid by using paulownia leaves as raw material

Abstract

The invention discloses a method for preparing the ursolic acid with the paulownia leaves as raw materials, comprising the following steps that: 1. the dry paulowina leaf powders with a particle size ranging from 20 to 60 meshes are taken and 3 to 5 times amount of the ethanol with a concentration over 90 percent is added in the dry paulowina leaf powders with carrying out the reflux extraction; the reflux extraction is conducted for 1 to 2 hours each time and goes for altogether 3 times; the ethanol-extracts are combined and are filtered so as to remove the impurities; the filtrates are driven to rest for over 12 hours after the ethanol is recycled and the precipitates are collected after filtration; the precipitates are dried and then the brown grey or black brown crude products of the ursolic acids are obtained. 2. the crude products of the ursolic acids are dissolved using the ethanol with a concentration ranging from 50 percent to 70 percent and the macroporous adsorption resin is used with carrying out the dynamic absorption; the solution is subject to the absorption till the solution approaches the saturated state before the solution is washed using 2 to 3 times of the deionized water by resin concentration for 3 to 5 times and then the obtained solution is eluted using the ethanol solvent with a concentration ranging from 85 percent to 99 percent; the precipitates are decolored using the activated carbon before the precipitates are crystalized for 2 to 3 times using the double solvents of the ethanol so as to obtain the target products. The advantages of the invention lie in that the goal of the industrialized batch production of the ursolic acids is realized with the paulownia leaves having wide sources as raw materials, and the purity and stability of the products both exceed 95 percent and no discharge of waste gas, waste residue and organic solvents exists in the invention.

Description

technical field [0001] The invention relates to a method for preparing ursolic acid with plants, in particular to a method for preparing ursolic acid with paulownia leaves (commonly known as paulownia leaves) as raw materials. Background technique [0002] Ursolic acid (Ursolic acid) is a macromolecular structure. It has a variety of biological activities and low toxicity. It can be used directly as a pharmaceutical raw material, or as a pharmaceutical and chemical intermediate, at the -OH, -COOH position or other positions of the five-membered ring By introducing other active groups on the surface, new pharmaceutical and chemical intermediates or finished substances can be developed. Due to the difficulty in the chemical synthesis of the five-membered ring and the market demand, ursolic acid has a high development value. [0003] At present, ursolic acid is mostly extracted from plants such as Ligustrum lucidum, hawthorn, Hedyotis diffusa, loquat leaves, Prunella vulgaris a...

AI Technical Summary

Problems solved by technology

[0003] At present, ursolic acid is mostly extracted from plants such as Ligustrum lucidum, hawthorn, Hedyotis diffusa, loquat leaves, Prunella vulgaris and Cornus officinalis, and is extracted by organic solvents, such as methanol, chloroform, dichloromethane, acetone, n-hexane The extraction of alkane, and then use petroleum ether, ether and ethyl acetate to remove impurities, etc., but this method has high production costs and cannot be mass-produced, and the use of organic solvents such as methanol and acetone is very polluting to the environment; The extraction method is difficult to achieve the production of ursolic acid with a purity ≥ 95%; although repeated solvent recrystallization methods can improve the purity of ursolic acid, repeated repetitions will increase the cost of solvents and limit the mass production of products