We examined the effects of many of the polyphenols present in green tea in different cell lines: MDAmb231, MDAmb468, MCF7 (mammary carcinoma cell lines), HeLa (a cervical carcinoma cell line), and HepG2 (an hepatocarcinoma cell line). Among the main polyphenols present in green tea—epigallocatechin, epicatechingallate, gallic acid, epigallocatechin-3-gallate (EGCG) and epicatechin—only EGCG inhibited the expression of genes typically involved in inflammatory processes as inducible nitric oxide synthase (iNOS or NOS II) and the interferon regulating factor-1 (IRF-1). Incubation of cells with EGCG leads to a decrease of the phosphorylation of transcription factor STAT-1α, whose activation is needed for the transcription of these genes, while other involved transcription factors such as NFκB, SP-1, AP-1 are not modulated. In conclusion, our study revealed that EGCG, by inhibiting STAT-1 activation, may play an important role in modulating the entire process of inflammation. It may be a promising candidate as a drug to modulate STAT-1α signal transduction.
Antiinflammatory action of EGCG, the main component of green tea, through STAT-1 inhibition
Tedeschi E.;Suzuki H.;Menegazzi M.
2002-01-01
Abstract
We examined the effects of many of the polyphenols present in green tea in different cell lines: MDAmb231, MDAmb468, MCF7 (mammary carcinoma cell lines), HeLa (a cervical carcinoma cell line), and HepG2 (an hepatocarcinoma cell line). Among the main polyphenols present in green tea—epigallocatechin, epicatechingallate, gallic acid, epigallocatechin-3-gallate (EGCG) and epicatechin—only EGCG inhibited the expression of genes typically involved in inflammatory processes as inducible nitric oxide synthase (iNOS or NOS II) and the interferon regulating factor-1 (IRF-1). Incubation of cells with EGCG leads to a decrease of the phosphorylation of transcription factor STAT-1α, whose activation is needed for the transcription of these genes, while other involved transcription factors such as NFκB, SP-1, AP-1 are not modulated. In conclusion, our study revealed that EGCG, by inhibiting STAT-1 activation, may play an important role in modulating the entire process of inflammation. It may be a promising candidate as a drug to modulate STAT-1α signal transduction.
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