Repletion of antioxidant status by EGCG and retardation of oxidative damage induced macromolecular anomalies in aged rats Vadivel Senthil Kumaran, Karpagavinayagam Arulmathi, Ravichandran Srividhya, Periandavan Kalaiselvi * Department of Medical Biochemistry, DR.ALM Postgraduate Institute of Basic Medical Sciences, University of Madras, Taramani Campus, Chennai 600 113, India Received 24 August 2007; received in revised form 24 October 2007; accepted 30 October 2007 Available online 7 November 2007 Abstract Ageing is defined as the loss of ability to maintain cellular homeostasis of an organism associated with the free radical-elicited oxi- dative damage to cellular macromolecules. The aim of this study was to evaluate the efficacy of epigallocatechin-3-gallate (EGCG), the key component of green tea catechins on attenuating the age associated oxidative perturbances by assessing the redox status in mitotic (liver) and post-mitotic (skeletal muscle) tissues of young and aged rats. From the results, we observed an increase in the marker for oxidative damage such as lipid peroxidation and protein carbonyl content in aged rats, when compared to young rats. This was accom- panied with decreased levels of both enzymic and non-enzymic antioxidants and redox index. On supplementation with EGCG (100 mg/ kg body weight by oral gavage for 30 days), the levels of lipid peroxidation and protein carbonyl content were significantly decreased in aged rats, possibly by enhancing the GSH redox status, and both enzymic and non-enzymic antioxidants status. In conclusion, this study supports the beneficial effect of EGCG in alleviating oxidative disturbances in ageing and retard the age associated derangements in both mitotic and post-mitotic tissues. Ó 2007 Elsevier Inc. All rights reserved. Keywords: Ageing; EGCG; Antioxidants; Liver; Skeletal muscle 1. Introduction Ageing is a process that results in the loss of cellular function with resultant increase in mortality and represents the major risk factor for a plethora of age related diseases (Squier, 2001). It was proposed 51 years ago that free rad- icals are one of the major factors involved in the ageing process (Harman, 1956). The main notion was that ageing is caused by the accumulation of free radical-elicited oxida- tive damage to various biological molecules in tissue cells. It is known that small, but significant amount of electrons which leak from the electron transport chain generate reac- tive oxygen species (ROS) as hydroxyl radicals (Leeuwen- burgh et al., 1999) and the superoxide radicals (Cadenas et al., 1977). ROS mediated lipid peroxidation and DNA damage is associated with a variety of chronic health prob- lems (Marnett, 2000). Under normal physiological condi- tions, the ROS generated by the respiratory chain is scavenged by enzymic and non-enzymic antioxidant sys- tems to prevent deleterious oxidative damage to the cell. As the organism ages, ROS production increases, while antioxidants status declines, leading to accumulation of age associated damaged macromolecules, which further enhances ROS production. This vicious cycle cannot be terminated, while it can be interrupted by intervention of antioxidants supplementation. Plant and food derived antioxidants have been found beneficial in protecting against several diseases and hence antioxidant therapy has become an attractive therapeutic strategy (Rice-Evans and Diplock, 1993). Tea (Camellia sinensis) has been 0531-5565/$ - see front matter Ó 2007 Elsevier Inc. All rights reserved. doi:10.1016/j.exger.2007.10.017 * Corresponding author. Tel.: +91 44 24541767; fax: +91 44 24540709. E-mail address: senthilvibms@yahoo.co.in (P. Kalaiselvi). www.elsevier.com/locate/expgero Available online at www.sciencedirect.com Experimental Gerontology 43 (2008) 176–183