Protective role of tannin-rich fraction of Camellia sinensis in tissue arsenic burden in Sprague Dawley rats

Abstract

<jats:p> The protective effect of green tea (Camellia sinensis) was tested against arsenic-induced toxicity. However, the possible role of tannins in green tea in alleviating hepatic and renal oxidative injury has also been studied. Administration of sodium arsenite (100 mg/kg/day) for 28 days in Sprague Dawley female rats resulted in significant reduction of biochemical parameters such as delta-aminolevulinic acid dehydratase (ALAD), reduced glutathione (GSH), glutathione peroxidase (GPx), superoxide dismutase (SOD) and elevation of thiobarbituric acid reactive substances (TBARS) and the index of nitrite/nitrate (NOx) levels. The tissue arsenic burden was increased after arsenic exposure for a period of 28 days. Green tea crude fraction (GTC) co-treated with sodium arsenite for 28 days caused significant (p &lt; .01) elevation of ALAD, GSH, GPx, SOD, and nitrate/nitrite levels and reduction of the TBARS level and tissue burden when compared to detannified green tea fraction (GTDT)-treated groups. The protective role of tannin-rich fraction of C. sinensis when compared to the detannified fraction was also confirmed by histological examinations. The greater activity of GTC than that of detannified green tea fraction correlates with the higher content of tannins in green tea. Overall, these results indicate that the tannin-rich green tea could have improved the defense mechanism against arsenic-induced oxidative stress and reduced the tissue arsenic burden. </jats:p>

Phytoremediation Potential, Photosynthetic and Antioxidant Response to Arsenic-Induced Stress of Dactylis glomerata L. Sown on Fly Ash Deposits

“…In the leaves of D. glomerata sown on fly ash deposits, the amount of free, bound and total phenolics was higher in comparison to the control site (137%, 140% and 137%, respectively) and it can be a response to As stress (r = 0.66, r = 0.76, and r = 0.66, respectively), indicating that As can promote their biosynthesis. Similar to our results, increased amount of phenolics under excess As in leaves was found in the leaves of Festuca rubra sown on fly ash deposits [13] and Camellia sinesis [151]. Results in this study show positive correlations between MDA and free, bound and total phenolics (r = 0.80, r = 0.93, and r = 0.82, respectively), suggesting that a high amount of MDA can be a signal for the activation of phenolics as antioxidants in order to maintain cellular redox homeostasis.…”

The role of antioxidant versus pro‐oxidant effects of green tea polyphenols in cancer prevention

“…This upregulation of phase II antioxidant defense was concurrent with less hepatic damage and inflammation. Tannin‐rich green tea increased phase II antioxidant defense better than de‐tannified green tea (same weight basis) 99. This indicates that the indirect antioxidant activity of green tea is due, in part, to tannin content.…”

Cellular Defensive Mechanisms of Tea Polyphenols: Structure-Activity Relationship

“…In another study, administration of green tea containing tannins was found to protect Sprague Dawley rats from arsenic-induced hepatic and renal oxidative injury by increasing the levels of GSH, GPx, and SOD and concurrently reducing the levels of lipid peroxidation and nitrite/nitrate. Moreover, the tannin-rich fraction of green tea exhibited a greater antioxidant activity than the detannified fraction, indicating that tannins at least partially contribute to the indirect antioxidant property of tea polyphenols [112]. EGCG was also found to exert similar protective effects against arsenic-induced hepatotoxicity in rats [113].…”