RESUMO
There is epidemiological evidence showing that drinking green tea can lower the risk of esophageal cancer (EC). The effect is mainly attributed to tea polyphenols and their most abundant component, (-)-epigallocatechin-3-gallate (EGCG). The possible mechanisms of tumorigenesis inhibition of EGCG include its suppressive effects on cancer cell proliferation, angiogenesis, DNA methylation, metastasis and oxidant stress. EGCG modulates multiple signal transduction and metabolic signaling pathways involving in EC. A synergistic effect was also observed when EGCG was used in combination with other treatment methods.
Assuntos
Catequina/análogos & derivados , Neoplasias Esofágicas/tratamento farmacológico , Antineoplásicos/química , Antineoplásicos/farmacologia , Catequina/química , Catequina/farmacologia , Proliferação de Células/efeitos dos fármacos , Metilação de DNA/efeitos dos fármacos , Humanos , Polifenóis/química , Transdução de Sinais/efeitos dos fármacos , CháRESUMO
An adsorption separation method using Polyamide-6 (PA) as an adsorbent was developed to separate catechins from green tea extract. The adsorption capacity of total catechins for PA was 193.128 mg g⻹ with an adsorption selectivity coefficient K(A)(B) of total catechins over caffeine 21.717, which was better than macroporous resin model HPD 600. The Langmuir model and the pseudo-second order mode were primely fitted to describe its equilibrium data and adsorption kinetics, respectively. PA column separation by two-step elution using water and 80% (v/v) aqueous ethanol was established to prepare catechins complex which contained 670.808 mg g⻹ total catechins and 1.828 mg g⻹ caffeine. It is considered that PA was a promising adsorbent for selective isolation of catechins.
