Aim: The present study was designed to investigate the effect of Saraca Indica flowers (SIF) extract and different fractions on in vitro aldose reductase (AR), high glucose induced cataract in goat lens and in vivo streptozotocin (STZ; 45 mg/kg, i.p) induced cataract in rats.
Materials and methods: Extract of flowers of Saraca Indica was prepared using different solvents and tested for inhibition against rat lens aldose reductase. Furthermore, active fraction was investigated against high glucose induced opacification of lens in ex vivo lens culture and STZ induced diabetic cataract in rats. Different doses of SIF (200 and 400 mg/kg) was administered once daily for eight weeks to STZ-induced diabetic rats. Tissue markers of oxidative stress were also determined at the end of the experiment. Identification of the bioactive component was attempted through HPLC and LC-MS analysis.
Results: Different fractions showed significant amount of aldose reductase inhibitory activity, where in ethyl acetate fraction produced maximum which may be due to high phenolic and flavonoid content. Rat lenses in media containing 20 mM glucose developed a distinctly opaque ring in 72 h and treatment with SIF extract at a concentration of 1 mg/ml lowered lens opacity in 72 h. In vivo experiments were performed with STZ induced diabetic rats. Prolonged treatment with ethyl acetate extract of SIF to STZ-induced diabetic rats decreased the blood glucose levels and inhibited the AR activity and delayed cataract progression in dose dependent manner.
Conclusion: The present study shows that ethyl acetate extract of SIF has pharmacologically active components with a potential to inhibit rat lens AR and also in vitro an antioxidant activity. These activities may prevent cataractogenesis in glucose containing lens organ cultures as well as in in vivo STZ induced diabetic rats.