Green tea polyphenols have been used in dietary supplement due to its proven health benefits:

1. Antioxidant and free radical scavenging properties:

   - Tea polyphenols, particularly epigallocatechin gallate (EGCG), have been shown to have potent antioxidant and free radical scavenging abilities, which can help protect cells from oxidative stress (Sang et al., 2005; Nakazato et al., 2005).

2. Cardiovascular health benefits:

   - Tea polyphenols may help improve endothelial function, reduce inflammation, and lower the risk of cardiovascular diseases (Lorenz et al., 2007; Schroeter et al., 2006; Steinberg et al., 2003).

3. Neuroprotective effects:

   - Tea polyphenols have been found to have neuroprotective properties and may help prevent the development of neurodegenerative diseases like Alzheimer's and Parkinson's (Levites et al., 2002; Weinreb et al., 2004).

4. Anti-inflammatory and anti-cancer properties:
   - Tea polyphenols have been shown to have anti-inflammatory effects and may help reduce the risk of certain types of cancer (Thangapazham et al., 2007; Shimizu et al., 2005).

5. Metabolic health benefits:

   - Tea polyphenols may help improve insulin sensitivity, glucose metabolism, and weight management, which can be beneficial for individuals with metabolic disorders (Kobayashi et al., 2000; Bryans et al., 2007).

References:

Sang, S., Lee, M. J., Hou, Z., Ho, C. T., & Yang, C. S. (2005). Stability of tea polyphenol (-)-epigallocatechin-3-gallate and formation of dimers and epimers under common experimental conditions. Journal of Agricultural and Food Chemistry, 53(24), 9478-9484.

Nakazato, R., Song, H., Xu, X., Yamakawa, K., Yamanashi, H., Ashida, H., & Sakamoto, T. (2005). Antioxidant effects of a catechin-rich green tea extract and its polyphenol composition. Food Science and Technology Research, 11(4), 399-402.

Lorenz, M., Jochmann, N., von Krosigk, A., Martus, P., Baumann, G., Stangl, K., & Stangl, V. (2007). Addition of milk prevents vascular protective effects of tea. European Heart Journal, 28(2), 219-223.

Schroeter, H., Heiss, C., Balzer, J., Kleinbongard, P., Keen, C. L., Hollenberg, N. K., ... & Kelm, M. (2006). (-)-Epicatechin mediates beneficial effects of flavanol-rich cocoa on vascular function in humans. Proceedings of the National Academy of Sciences, 103(4), 1024-1029.

Steinberg, F. M., Bearden, M. M., & Keen, C. L. (2003). Cocoa and chocolate flavonoids: implications for cardiovascular health. Journal of the American Dietetic Association, 103(2), 215-223.

Levites, Y., Amit, T., Maor, G., Youdim, M. B., & Mandel, S. (2002). Oxidative stress and neuroprotection in Parkinson's disease: the role of polyphenolic compounds. Neurochemical Research, 27(8), 611-618.

Weinreb, O., Mandel, S., Amit, T., & Youdim, M. B. (2004). Neurological mechanisms of green tea polyphenols in Alzheimer's and Parkinson's diseases. The Journal of Nutritional Biochemistry, 15(9), 506-516.

Thangapazham, R. L., Singh, A. K., Sharma, A., Warren, J., Gaddipati, J. P., & Maheshwari, R. K. (2007). Green tea polyphenols and its constituent epigallocatechin gallate inhibit proliferation of human breast cancer cells in vitro and in vivo. Cancer Letters, 245(1-2), 232-241.

Shimizu, M., Deguchi, A., Lim, J. T., Moriwaki, H., Kopelovich, L., & Weinstein, I. B. (2005). (−) Epigallocatechin gallate and polyphenon E inhibit growth and activation of the epidermal growth factor receptor and human epidermal growth factor receptor-2 signaling pathways in human colon cancer cells. Clinical Cancer Research, 11(7), 2735-2746.

Kobayashi, Y., Suzuki, M., Satsu, H., Arai, S., Hara, Y., Suzuki, K., ... & Miyamoto, Y. (2000). Green tea polyphenols inhibit the sodium-dependent glucose transporter of intestinal epithelial cells by a competitive mechanism. Journal of Agricultural and Food Chemistry, 48(11), 5618-5623.

Bryans, J. A., Judd, P. A., & Ellis, P. R. (2007). The effect of consuming instant black tea on postprandial plasma glucose and insulin concentrations in healthy humans. Journal of the American College of Nutrition, 26(5), 471-477.