Flavonoids Of Green Tea And Its Antitumor Effect

Tea is one of the most widely consumed beverages in the world, next only to water.It hasbeen 5000 years since the appearance of tea and its healthy benefits have also beenrecognised ,but the history of researches on the assotiation of its components and its positiveactivities is of no more than 30 years. There are growing interests in the green tea for itshealthy effects .In this experiment, 70% ethanol was used to get the extraction of green tea and thecontent of flavonoids in the extraction determined by spectrometry is 21.76% ,while theEGCG in the extraction is 8.91% determined by high performance liquid chromatogram. Invitro, MTT assay, acridine orange(AO)fluorescence stainning, Flow CytoMetry(FCM) ,and DNA ladder assay were used to study the abilities of the extraction to inhibit the growthand induce the apoptosis of gastric cancer cell line BGC823. The result of MTT showed thatgreen tea extraction could suppress the proliferation of BGC823 in a dose-dependentmanner. BGC823 cells stained with acridine orange showed "apoptotic bodies" in the nucleus.The result of FCM showed that it could arrest the cells in S phase and its apoptosis peak wasmarked. The DNA ladder test also showed the characteristics of apoptosis.The suppressive effect of the green tea extraction on S180 sarcoroma bearing mice wasstudied, and the results showed that the green tea extraction could significantly inhibit thegrowth of sarcoma S180, the inhibition rate reached to 52.65% when the concentration of thisextraction was 200mg/kg.The arising of the level of TNF-α in the blood serum of the greentea extraction treated mouse suggested that the extraction may have immunomodulatoryeffects. The suppressive effect of Epigallocatechin-3-Gallate(EGCG) which is the purecomponent of tea catechins on gastric cancer cell line BGC823 was also studied. The resultsshowed that the effect of 40μg/ml EGCG was similar to the effect of 150μg/ml the extraction.It could inhibit the growth of BGC823 via inducing its apoptosis.The experiment on the effect of the extraction and EGCG on the proliferation of mousespleen cells showed that they could stimulate the proliferation of spleen cells both used singlyand with ConA in a concentration-dependant way. The research of their effect on LPSstimulated macrophage RAW264.7 NO release showed that it could reduce the NOproduction in a dose-dependant manner.