Evaluation of Phytochemical Content of White Tea Clone 100 and Changes the Expression of Tumor Suppressor Genes on Colorectal Cancer Cell Line HCT116

Aim/Background: Colorectal carcinoma cancer is one of the main types of cancer with high death rate of patients, according to their non-healthy lifestyle. In this research, we evaluated inhibitory of white tea clone 100 extract on colorectal cancer cell line HCT‑116, and its effectiveness in expression level of three tumor suppressor genes. Materials and Methods: Total polyphenolic content in all samples were measured using the Folin–Ciocalteu method, and free radical adsorption investigated by 2, 2‑diphenyl‑1‑picrylhydrazyl (DPPH) assay. 3‑(4, 5‑dimethylthiazol‑2‑yl)‑2,5‑diphenyltetrazolium bromide (MTT) assay was used to evaluate the white tea extract inhibitory effect on HCT‑116 cells. Results: Among different extraction methods, the white tea aqueous extracts produced the highest amount of polyphenols and DPPH radical scavenging activity (36.67 ± 0.54 mg gallic acid equivalent/g dry weight and 71.74% ± 0.42%, respectively). Cell survival analysis in the MTT assay indicated that aqueous white tea extract could reduce the viability of HCT‑116 cells in 8, 16, and 24 h considerably, related to the concentration‑dependent manner. The real‑time polymerase chain reaction results indicated the significantly increased expression level (P < 0.05) of tumor suppressor genes DCC, TGFBR2, and P53 in the concentration of 1000 μg/ml at 24 h. Conclusion: White tea aqueous extract because of having hydroxyl group in its structure at optimal concentration in all three times of experimental, could lead to a positive changes effect on gene expression in the tumor suppressor family.