Isorhamnetin-3-glucoside alleviates oxidative stress and opacification in selenite cataract in vitro V. Gayathri Devi a , B.N. Rooban a , V. Sasikala a , V. Sahasranamam b , Annie Abraham a, * a Department of Biochemistry, University of Kerala, Kariavattom, Thiruvananthapuram 695581, Kerala, India b Regional Institute of Ophthalmology, Medical College, Thiruvananthapuram 695037, Kerala, India article info Article history: Received 2 October 2009 Accepted 30 May 2010 Available online 8 June 2010 Keywords: Antioxidants Flavonoids IR3G Oxidative stress Selenite cataract abstract Oxidative stress has long been recognized as an important mediator in the pathogenesis of cataract and the goal of this study was to determine the efficacy of isorhamnetin-3-glucoside (IR3G) in alleviating the toxicity induced by sodium selenite in in vitro culture condition. IR3G is the bioactive flavonoid isolated and characterized from the leaves of Cochlospermum religiosum. Enucleated rat lenses were maintained in organ culture containing M-199 medium alone (G-I), supplemented with 0.1 mM selenite (G-II) and sel- enite + 25 lg/ml IR3G (G-III). Treatment to G-III was from the second to fifth day while selenite admin- istration to G-II & III was done on the third day. The antioxidant potential of the compound was assessed by Cu 2+ induced lipoprotein diene formation and superoxide scavenging assays. Morphological examina- tion of the lenses also gave a supporting data. Antioxidant enzymes-superoxide dismutase (SOD), catalase and concentration of reduced glutathione (GSH) were significantly lower, while TBARS showed an increase in G-II than that in G-III and G-I lenses. Activity of Ca 2+ -ATPase was decreased and level of cal- cium was increased in G-II than G-III and G-I lenses. These data suggest that IR3G is able to significantly retard selenite cataract in vitro by virtue of its antioxidant property. Ó 2010 Elsevier Ltd. All rights reserved. 1. Introduction Cataract is the leading cause of blindness world wide and oxida- tive stress has been identified as an initiating factor for its develop- ment (Ottonello et al., 2000). At present the most effective treatment of cataract is the surgical extirpation of the opacified lens, post operative complications and the cost of cataract sur- gery may place it beyond the reach of less affluent individuals (Bockelbrink et al., 2008). However, a delay of 10 years in the onset of cataract by any means would be expected to halve the number of cataract extractions (Brian and Taylor, 2001). There is no single universally accepted pharmacological agent that has emerged to either inhibit or reverse the progression of cataract. Hence, it is important to look into alternative pharmacological measures for the treatment of this disorder. Selenite cataract has been proven to be an extremely rapid and convenient model for nuclear cataracts (Ostadalova et al., 1978). This model has many attributes that permit evaluation of protec- tive agents acting on perturbations that lead to decreased lens transparency (Shearer et al., 1997). The biochemical processes such as oxidative stress, altered epithelial metabolism, calcium accumu- lation, calpain-induced proteolysis, crystallin precipitation, phase transition, and cytoskeletal loss occur during the development of selenite-induced cataract (Shearer et al., 1997). Various medicinal plants and bioactive components have been reported to render protective effect against selenite cataract (Gupta et al., 2003, 2005; Lija et al., 2006; Biju et al., 2007; Rooban et al., 2009), by vir- tue of antioxidant effect. Recently much interest has been generated in the search for phytochemical therapeutics, as they are largely free from adverse side effects and are economical. Previous studies by our research group have clearly demonstrated flavonoids isolated from Emilia sonchifolia, Vitex negundo and terpenoids from Dregea volubilis, ex- hibit good antioxidant and anticataractogenic potential (Lija et al., 2006; Biju et al., 2007; Rooban et al., 2009). C. religiosum (Linn.) of the family, Cochlospermaceae, is a small or medium sized decidu- ous tree. Earlier phytochemical reports show that only a dihydrof- lavone, naringenin was isolated from the flowers of C. religiosum (Linn.) (Ram and Mehrrotra, 1999). The dried leaves and flowers of the tree are used as stimulant (Chopra et al., 1999). Antioxidants act as a major defense against radical mediated toxicity by protect- ing the damages caused by free radicals (Lee et al., 2003). Among the natural antioxidants, the flavonoids widely distributed in the plant kingdom are reported to have beneficial health effects mostly ascribed to their scavenging, metal chelating and antioxidant ac- tion (Kameoka et al., 1999). Our preliminary studies with the 0887-2333/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.tiv.2010.05.021 * Corresponding author. Tel.: +91 471 2418078/2532220; mobile: +91 9447246692; fax: +91 471 2307158. E-mail address: annieab2@yahoo.co.in (A. Abraham). Toxicology in Vitro 24 (2010) 1662–1669 Contents lists available at ScienceDirect Toxicology in Vitro journal homepage: www.elsevier.com/locate/toxinvit