Separation of catechin compounds from different teas

Abstract

Catechin compounds from Korean and Chinese green tea, and pu-erh, Indian black, Longjing, Tieguanyin, Bamboo, Jasmine, Oolong, Flower, Red teas, as potential anticancer and antioxidant components, were target material in this work. After extracting the green tea with water at 50 degrees C for 4 h, the extract was partitioned with water/chloroform, which was best suited to remove caffeine impurity from the extract. Further, the resulting extract was partitioned with water/ethyl acetate to deeply purify the five catechin compounds epigallocatechin, (+) catechin, epicatechin, epigallocatechin gallate and epicatechin gallate. The extracted samples were analyzed by reversed-phase high performance liquid chromatography. The mobile phase applied was the binary system of A (water/acetic acid, 100/0.1 vol%) and B (acetonitrile/acetic acid 100/0.1 vol%) from 90:10 to 70:30 (A:B vol%) in a linear gradient over 30 min time. The amount of catechin compounds extracted from Chinese green tea was 114.65% higher than from the Korean green tea. Comparing various tea sorts, the green teas contained more than 1.7 times of the five catechin compounds contained in other teas.

Ultrahigh pressure extraction as a tool to improve the antioxidant activities of green tea extracts

“…Conventional extraction was performed as described by Jin et al (Jin, Jin, & Row, 2006) with some modifications. Sample was weighed exactly (10 g) in a three-neck flask, and 200 ml 50% ethanol extraction solvent was added.…”

Effect of Extraction Conditions on the Soluble Oxalate Content in Water Infusions of Green and Herbal Teas

“…Podjęte badania miały także na celu sprawdzenie na ile opisywane w literaturze alternatywne metody ekstrakcji wykorzystywane przy oznaczaniu zawartości innych bioaktywnych związków w herbatach zielonych i czarnych, m.in. katechin [2,11,13,20,23], mogą mieć wpływ na wyniki oznaczania rozpuszczalnych szczawianów.…”

Separation of major catechins from green tea by ultrahigh pressure extraction

“…The four major catechins and caffeine in the extracts were determined using the HPLC procedure of Yinzhe et al (2006). Stock solutions of four catechins, gallic acid, and caffeine were prepared by dissolving weighed quantities of commercial standards into water.…”

“…Then, the extracts were filtered through a syringe filter. The extraction solution was centrifuged at a speed of 4000 rpm for 10 min, and the supernatant was collected, evaporated under vacuum at 40 • C, and stored at 4 • C in refrigerator for subsequent HPLC determination (Ho and Jin, 2006).…”

“…Recently it had been successfully used for extraction of lycopene from tomato paste waste (Jun, 2006), ginsenoside from Korean red ginseng (Kim et al, 2007), anthocyanins from grape skins (Corrales et al, 2008(Corrales et al, , 2009, and corilagin from longan fruit pericarp (Nagendra Prasad et al, 2010). Many efforts successfully separated tea catechins using supercritical CO 2 (Chang et al, 2000), soxhlet extraction (Price and Spitzer, 1993) and organic solvent extraction (Ho and Jin, 2006). However, to our knowledge, no study has been carried on separating catechins using ultrahigh pressure extraction.…”