Andichettiar Thirumalaisamy Sivashanmugam and Tapan Kumar Chatterjee
Cataracts are the leading cause of blindness worldwide but safe and effective pharmacological intervention is lacking to prevent cataractogenesis. Glucose-induced cataractogenesis in vitro model serves as a good model. The objective of the present study was to evaluate the anticataractogenesis and antioxidant effect of the ethanol and chloroform extracts of Polyalthia longifolia (Sonner.) Thw. (Annonaceae) leaves against glucose-induced cataractogenesis using goat lenses. Goat lenses were incubated in artificial aqueous humor containing 55 mM glucose alone, simultaneously with the ethanol and chloroform extracts of Polyalthia longifolia leaves and standard drug, vitamin E. Incubation with high concentration glucose-induced lens opacification started in 8-10 h and the lens was completely cataractous by the end of 72 h. Simultaneous treatment with plant extracts or vitamin E reversed this opacification. The lens homogenate of cataractous lenses were found to have significantly (P < 0.01) increased levels of total protein, lipid hydroxides and malondialdehyde, while there was a decrease in Ca2+-ATPase and Cu2+-induced lipoprotein dienes. There was increase in the levels of both the enzymatic (catalase, superoxide dismutase, glutathione peroxidase and glutathione reductase) and non enzymatic (glutathione) antioxidants. Both the extracts and vitamin E reversed these changes. Based on the results obtained from the present study, it can be understood that the leaves of Polyalthia longifolia possess protection against glucose-induced cataractogenesis. Potential leads for clinical use in the prevention of cataract can be identified by isolating and identifying the active phytoconstituents.
