Anticataract Activity of Forskolin by Inhibiting Polyol Pathway for the Prevention of Diabetic Complication

Background: Cataract is the opacification or optical dysfunction of the crystalline lens. Diabetes has been considered to be one of the major risk factors of cataract. Objective: The present study was designed to evaluate the anticataract activity of antioxidants such as Coleus forskohlii (CF) Briq and its phytoconstituent forskolin (FS) which were subjected to prevent cataract formation in vitro on glucose‑induced cataract model. Materials and Methods: Goat lenses were incubated in Krebs‑Ringer bicarbonate buffer pH 7.5 (supplemented with Taxim and streptomycin) containing 55 mM glucose (cataractogenesis) with fidarestat; CF methanolic extract; and FS at a concentration of 1 µg/mL, 100 µg/mL, and 10 µg/mL for 24 hr at 37°C with 5% CO₂ and 95% air. Glucose‑induced opacification of goat lens began 8–10 hr after incubation and was complete in 24 hr. Polyol (galactitol) levels in incubated lenses were estimated spectrophotometrically. Results: Cataractous lenses showed higher content of galactitol. However, lens treated with fidarestat, CF methanolic extract, and its phytoconstituent FS showed lower content of galactitol. Conclusion: CF and FS prevented the formation and progress of cataract by glucose, as evidenced by lens transparencies with photographic evaluation and lens galactitol levels.