Green tea or its concentrated extract is coveted for its health promoting catechin-like polyphenols, especially epigallocatechin-3-gallate (EGCG). However, its amicable efficacy is now being doubted considering the recent occurrence of several cases of hepato- and nephrotoxicity, after the ingestion of EGCG-fortified (≥85–90%) nutritional supplements. Therefore, the current study was carried out to ascertain the effect of green tea leaves extract (GTE), having low EGCG content (73.8%), on liver and kidney functions of male Wistar rats using various in vivo experiments and in vitro radical scavenging activity. In terms of acute toxicity, GTE was observed to be safe when delivered at a dosage of 2000 mg kg−1 body weight (BW). Oral delivery of GTE for 28 days at a concentration of 200 mg kg−1 BW/day did not trigger sub-acute toxicity to the liver and kidneys, as per serum biochemical analyses and histopathological examination. In contrast, GTE counteracted the effects of carbon tetrachloride (a potent hepato-degenerative compound) on the liver. Furthermore, increase in high-density lipoprotein―cholesterol with concomitant lowering of serum triglycerides and low-density lipoprotein―cholesterol were noticed in GTE-treated rats. These findings suggest that low EGCG containing GTE, with appreciable antioxidant activity (IC50 = 53.18–71.28 μg mL−1), can serve as a hepatoprotective, hypolipidemic, and hypocholesterolemic ingredient.
Babu, P.V.A., Sabitha, K.E., and Shyamaladevi, C.S. (2006). Therapeutic effect of green tea extract on oxidative stress in aorta and heart of streptozotocin diabetic rats. Chemico-Biological Interactions, 162(2): 114–120.
Benzie, I.F. and Strain, J.J. (1996). The ferric reducing ability of plasma (FRAP) as a measure of “antioxidant power”: the FRAP assay. Analytical Biochemistry, 239(1): 70–76.
Brand-Williams, W., Cuvelier, M.E., and Berset, C.L.W.T. (1995). Use of a free radical method to evaluate antioxidant activity. LWT – Food Science and Technology, 28(1): 25–30.
Chan, P.C., Ramot, Y., Malarkey, D.E., Blackshear, P., Kissling, G.E., Travlos, G., and Nyska, A. (2010). Fourteen-week toxicity study of green tea extract in rats and mice. Toxicologic Pathology, 38(7): 1070–1084.
Chen, Z.Y. and Chan, P.T. (1996). Antioxidative activity of green tea catechins in canola oil. Chemistry and Physics of Lipids, 82(2): 163–172.
Dahiya, S., Rani, R., Dhingra, D., Kumar, S., and Dilbaghi, N. (2018). Conjugation of epigallocatechin gallate and piperine into a zein nanocarrier: implication on antioxidant and anticancer potential. Advances in Natural Sciences: Nanoscience and Nanotechnology, 9(3): 035011.
Das Purkayastha, M., Das, S., Manhar, A.K., Deka, D., Mandal, M., and Mahanta, C.L. (2013). Removing antinutrients from rapeseed press-cake and their benevolent role in waste cooking oil-derived biodiesel: conjoining the valorization of two disparate industrial wastes. Journal of Agricultural and Food Chemistry, 61(45): 10746–10756.
Essex, K., Mehdi, A., and Shibeeb, S. (2019). Green tea consumption does not adversely affect kidney function and haematological parameters. Food and Public Health, 9(3): 79–83.
Galati, G., Lin, A., Sultan, A.M., and O’Brien, P.J. (2006). Cellular and in vivo hepatotoxicity caused by green tea phenolic acids and catechins. Free Radical Biology and Medicine, 40(4): 570–580.
He, J., Xu, L., and Le Yang, X.W. (2018). Epigallocatechin gallate is the most effective catechin against antioxidant stress via hydrogen peroxide and radical scavenging activity. Medical Science Monitor, 24: 8198–8206.
Hotta, H., Nagano, S., Ueda, M., Tsujino, Y., Koyama, J., and Osakai, T. (2002). Higher radical scavenging activities of polyphenolic antioxidants can be ascribed to chemical reactions following their oxidation. Biochimica et Biophysica Acta (BBA) – General Subjects, 1572(1): 123–132.
Hu, J., Webster, D., Cao, J., and Shao, A. (2018). The safety of green tea and green tea extract consumption in adults – results of a systematic review. Regulatory Toxicology and Pharmacology, 95: 412–433.
Kakkar, P., Das, B., and Viswanathan, P.N. (1984): A modified spectrophotometric assay of superoxide dismutase. Indian Journal of Biophysics and Biochemistry ,21(2): 130–132.
Lambert, J.D., Kennett, M.J., Sang, S., Reuhl, K.R., Ju, J., and Yang, C.S. (2010). Hepatotoxicity of high oral dose (−)-epigallocatechin-3-gallate in mice. Food and Chemical Toxicology, 48(1): 409–416.
Muramatsu, K., Fukuyo, M., and Hara, Y. (1986). Effect of green tea catechins on plasma cholesterol level in cholesterol-fed rats. Journal of Nutritional Science and Vitaminology, 32(6): 613–622.
Oketch-Rabah, H.A., Roe, A.L., Rider, C.V., Bonkovsky, H.L., Giancaspro, G.I., Navarro, V., Paine, M.F., Betz, J.M., Marles, R.J., … and Ko, R. (2020). United States Pharmacopeia (USP) comprehensive review of the hepatotoxicity of green tea extracts. Toxicology Reports, 7: 386–402.
Park, K.S. (2018). Nonclinical and clinical safety studies on green tea extracts. Journal of Natural and Ayurvedic Medicine. 2(4): 000136.
Salminen, W.F., Yang, X., Shi, Q., Greenhaw, J., Davis, K., and Ali, A.A. (2012). Green tea extract can potentiate acetaminophen-induced hepatotoxicity in mice. Food and Chemical Toxicology, 50(5): 1439–1446.
Schönthal, A.H. (2011). Adverse effects of concentrated green tea extracts. Molecular Nutrition & Food Research ,55(6): 874–885.
Senthilkumar, S.R., Sivakumar, T., Arulmozhi, K.T., and Mythili, N. (2017). FT-IR analysis and correlation studies on the antioxidant activity, total phenolics and total flavonoids of Indian commercial teas (Camellia sinensis L.) – a novel approach. International Journal of Scientific Research in Biological Sciences, 6(3 ): 1–7.
Shimamura, T., Sumikura, Y., Yamazaki, T., Tada, A., Kashiwagi, T., Ishikawa, H., Matsui, T., Sugimoto, N., Akiyama, H., and Ukeda, H. (2014). Applicability of the DPPH assay for evaluating the antioxidant capacity of food additives – inter-laboratory evaluation study. Analytical Sciences, 30(7): 717–721.
Wang, D., Wei, Y., Wang, T., Wan, X., Yang, C.S., Reiter, R.J., and Zhang, J. (2015). Melatonin attenuates (–)‐epigallocatehin‐3‐gallate‐triggered hepatotoxicity without compromising its downregulation of hepatic gluconeogenic and lipogenic genes in mice. Journal of Pineal Research, 59(4): 497–507.
Wang, H., Chen, L., Weng, L.L., Zhang, M.Y., and Shen, Q. (2014). Surface properties and dissolution kinetics of tea polyphenols. Journal of Adhesion Science and Technology, 28(24): 2416–2423.
Wolfram, S. (2007). Effects of green tea and EGCG on cardiovascular and metabolic health. Journal of the American College of Nutrition, 26(4): 373S–388S.