Technique for extracting and purifying oleanolic acid and ursolic acid from sweet tea

The invention discloses a technique for extracting and purifying oleanolic acid and ursolic acid from sweet tea, which includes the following steps: absolute ethyl alcohol is adopted for ultrasonic extraction and suction filtration; combined extract is concentrated, so that an extract is obtained, chloroform is used for dissolving the obtained extract, and after recovering chloroform by concentration, a brown extract is obtained; 5 percent of sodium hydroxide is used for carrying out alkali dissolution and acid precipitation on the extract, and a method, such as silica gel column chromatography separation, is carried out on precipitate, so that high-purity oleanolic acid and ursolic acid are obtained; by adopting a high-performance liquid chromatography method to carry out content determination, the purities of both oleanolic acid and ursolic acid are 90 percent or more, the yield of oleanolic acid is 20mg/100g or more, and the yield of ursolic acid is 90mg/100g or more. The technique disclosed by the inventi