Theaflavin-2 (TF-2), a major component of black tea extract, induces apoptosis of human colon cancer cells and suppresses serum-induced COX-2 expression [1]. Here, we explored the mechanisms for activation of apoptosis, evaluated the impact on inflammatory genes in a broader panel of cells and tested whether topical anti-inflammatory effects could be observed in vivo. TF-2 triggered apoptosis in five other transformed cancer cell lines, inducing cell shrinkage, membrane blebbing, and mitochondrial clustering within 3 h of treatment. Among a set of pro-apoptotic genes, TF-2 quickly induced the up-regulation of P53 and BAX, suggesting mitochondria as the primary target. Using a cell model for inflammatory response, we showed that TF-2 suppressed the TPA-induced COX-2 gene expression, and also down-regulated TNF-α, iNOS, ICAM-1, and NFκB. A reporter gene assay showed that TF-2 down-regulated COX-2 at the transcriptional level. We also demonstrated that TF-2 exhibited anti-inflammatory activity in two mouse models of inflammation. Topical application with TF-2 significantly reduced ear edema and produced a pattern of gene down-regulation similar to that observed in the cell model. These results suggest that the anti-inflammatory and pro-apoptotic activity of TF-2 may be exploited therapeutically in cancer and other diseases associated with inflammation.

Epigallocatechin gallate (EGCG) and flavonols are important phenolic compounds in green tea. These compounds are sensitive to thermal condition and their structural alteration results in making browning the green tea infusion. This study aimed to research the interaction between EGCG and flavonols during thermal infusion. EGCG and flavonols model solutions were prepared based on concentration in green tea infusion, and their colors appearance and attributes were analyzed in 10 h by thermal treatment. Results showed that kaempferol, quercetin, and myricetin accelerated the oxidation of EGCG and made the model solution browning. HPLC analysis revealed there was an obvious shift of a broaden peak in the mixed model solution of EGCG and flavonols after thermal treatment. This broaden peak was further purified on HPLC and solid phase extraction methods to yield colored complexes. The complexes showed the maximal absorption around 424, 442, and 482 nm. MS/MS analysis revealed that the complexes possessed of three components those were consisted of the interaction between EGCG and myricetin. These results indicated that the interaction between EGCG and flavonols might form complexes during thermal treatment, The complexes were contributed to make green tea infusion browning.

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