Green tea catechins suppress basic fibroblast growth factor both in vitro and in vivo.

Epigallocatechin gallate (EGCG) is the most abundant catechin compound found in green tea and has been shown to act as anti‐angiogenic agent, supressing the pro‐angiogenic factors like vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) but the precise mechanism is not yet known. On the basis of previous reports and with the help of micro array data, which showed suppression of bFGF by epicatechin gallate (ECG), we found that ECG and EGCG suppressed bFGF expression at the transcription and translation levels. The RT‐PCR and Western analysis using catechin‐treated cells showed that EGCG/ECG suppressed bFGF in the most significant manner as compared to other catechins, but did not inhibit VEGF expression. To investigate further mechanism, we examined several signaling pathways using known inhibitors; interestingly, only lactacystin treatment affected EGCG‐induced bFGF suppression in human colorectal cancer cells. It suggests that EGCG may facilitate protein degradation of bFGF. Finally, animal experiment was performed using Min mice. The tumor load and tumor number were significantly less in EGCG treated mice. The ELISA assay carried out using the small intestinal tissue samples from these min mice, showed significant decrease in mice fed with EGCG. All the data were supporting to prove the hypothesis of down regulation of bFGF by EGCG.