PURPOSE: To extract a tannin fraction, particularly a catechin compound in high yield, by eluting caffeine from a water-soluble extract of green tea leaves (Thea sinensis L.) or/and a gambir (Uncaria gambin Rubiaceae), extracting the residual liquid continuously with ether, and carrying out the above-mentioned operation at a low temperature under shielded light.
CONSTITUTION: A water-soluble substance is extracted from green tea leaves (Thea sinensis L.) and/or a gambir (Uncaria gambin Rubiaceae) with a solvent, e.g. water, acetone-water or a lower alcohol-water, etc., and the resultant extract is then brought into contact with a polar solvent, e.g. chloroform, to elute caffeine converting into an inhibitory factor in extracting a catechin compound. The resultant residual liquid after eluting the caffeine is then continuously extracted with ether, and all the above-mentioned operations are carried out at a low temperature under shielded light, e.g. 40°C or below, to suppress the decomposition of tannin and give advantageously the aimed tannin fraction, particularly catechin compound useful as an anitoxidant for improving the prevention quality of foods and cosmetics.
UCHIDA YOSHIHIRO
FUJIKAWA AKIO
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