Method for extracting persimmon leaf flavone with content of more than or equal to 85 to 98 percent from persimmon leaf

Abstract

The invention discloses a method for extracting persimmon leaf flavone with content of more than or equal to 85 to 98 percent from a persimmon leaf. The method comprises the following steps of: grinding the persimmon leaf; performing microwave extraction for 1 to 5 times by using water in an amount which is 2 to 10 times that of the persimmon leaf, wherein the pH value of the water is 10 to 14, extraction at each time lasts for 10 to 60 minutes and the extraction temperature is between 30 and 60 DEG C; combining extracting solution and adjusting the pH value to be 5 to 7; adding a flocculation clarifying agent; stirring, standing and filtering; performing ultrafiltration membrane purification and reverse osmosis (RO) membrane dehydration on the filtrate; adjusting the pH value of concentrated solution to be 4 to 5; extracting the obtained concentrated solution by using ethyl acetate for 2 to 6 times; concentrating the extraction liquid; and drying to prepare the persimmon leaf flavones. By the method, the process is simple; the production cost is low; the extraction time is short; environmental pollution is small; and the flavonoids content of the extract is high and can reach 85 to 98 percent.

Description

technical field [0001] The invention relates to the extraction of flavonoids, in particular to a method for extracting flavonoids from persimmon leaves with a content of 85-98%. Background technique [0002] The main active ingredients in persimmon leaves are flavonoids. The total content of flavonoids in persimmon leaves is 121.3mg / 100g. The flavonoids that have been found so far include astragaloside (molecular weight: 446.36), isoquercetin (338.27), Naphthol 3-o-β-D-glucoside, kaempferol (286.24), quercetin (338.27), kaempferol 3-o-α-L-rhamnoside, kaempferol 3-β- D - xyloside, kaempferol 3- o - α - L - arabinoside, quercetin 3 - o - [ 2″- o - (3. 4.5 - trihydroxybenzoyl) ] - glucoside, Rutin (664.57), hyperoside (quercetin-3-galactoside), myricetin (464.38), astragalus glycoside, etc., the sugars combined with flavonoid glycosides are all monosaccharides, the molecular weight Both are less than 1000. Therefore, the molecular weights of flavonoids in persimmon leaves ar...

AI Technical Summary

Problems solved by technology

This method uses a macroporous resin for purification, which is cumbersome to operate, has a long cycle, and requires heating processes such as steam, which consumes a large amount of ethanol and is costly; (4) Chinese patent CN 101637492A uses 70% ethanol for water bath reflux extraction or Ethanol with a concentration of 70% is extracted by microwave heating and reflux or 70% ethanol is extracted by ultrasonic heating and reflux, and purified with a macroporous resin. This method also needs to use heating processes such as steam, which is high in cost, long in cycle, and cumbersome. (5) Chinese patent CN 101322737A adopts low-carbon alcohol extraction, macroporous resin is purified, and the method of ethyl acetate extraction obtains flavonoid extract content to be 80-98%, but this method also needs to adopt heating process such as steam, consumes The amount of ethanol used is large, the time is long, and the cost is high; (6) Chinese patent CN 1709542A adopts a two-phase extraction method, extracts with ethanol, two-phase extraction, and back-extracts with ethyl acetate to obtain a flavonoid content of 12.1%. This method Organic reagents such as ammonium sulfate are required, and the content of flavonoids is low, so it is not suitable for human use