Green tea (Camellia sinensis) alleviates arsenic‐induced damages to DNA and intestinal tissues in rat and in situ intestinal loop by reinforcing antioxidant system

This study elucidates the protective role of Green tea (Camellia sinensis or CS) against arsenic‐induced mutagenic DNA‐breakage/intestinal (small) damages in female rats. Intestinal epithelial cells receive ingested arsenic initially. Though, the possibility of damages in this tissue is immense and the therapeutic strategies against this damage are of great concern, reports on either issue are scanty. Our earlier study on arsenic‐exposed human unveils a link between carcinogenesis and mutagenic DNA damage. Here, we demonstrate that supplementation of CS‐extract (10 mg/mL water) with NaAsO₂ (0.6 ppm)/100 g b.w. for 28 days to rats offered a significant protection against arsenic‐induced oxidative damages to DNA and intestinal (small) tissues by buttressing antioxidant systems. Necrotic and apoptotic damages and their CS‐protection are shown in DNA‐fragmentation, comet‐assay, and histoarchitecture (hematoxylin and eosin and periodic acid‐schiff staining) results. Only arsenic exposure significantly decreased intestinal superoxide dismutase, catalase activities, and level of soluble thiol with a concomitant increase in malondialdehyde/conjugated dienes. Alteration of serum necrotic marker lactate dehydrogenase and the metabolic inflammatory marker c‐reactive protein also indicate the impairment may be occurring at transcription and/or cellular signal transduction level. In addition, in situ incubation in rat intestinal loop filled for 24 h with NaAsO₂ alone (250 µM) or with aqueous CS‐extract (250 mg/mL) suggests that small intestinal epithelial cells are significantly protected by CS against arsenic‐associated necrotic/mutagenic damages, which is observed in DNA‐breakage studies. In conclusion, besides intensifying endogenous antioxidant system, CS polyphenols also offer a direct role on free radical scavenging activity that is associated to the protection from mutagenic DNA‐breakages and prevention of tissue necrosis/carcinogenesis generated by arsenic. © 2014 Wiley Periodicals, Inc. Environ Toxicol 30: 1033–1044, 2015.