Cataract development in sand and galactosemic rats fed a natural tomato extract.

This study investigated the effect of a natural tomato extract (TE) on cataract formation in two animal models. A TE containing 5% lycopene was included in the diet of diabetic sand rats at 0.2%, and Sprague Dawley rats were fed a high-galactose diet (30 g/100 g of diet), supplemented with either the lycopene-rich extract at concentrations of 0.2, 0.4, and 0.8% or BHT (0.2%). TE had no significant effect on plasma glucose levels or cataract development in sand rats; however, in rats maintained on a diet rich in galactose, both BHT and TE decreased cataract incidence, and grades were lower than in control animals. In addition, lens protein and reduced glutathione levels were higher and aldose reductase activity was lower than in the control group. The results suggest that antioxidants act as protective agents when oxidative stress is a primary cause of cataract formation but may be less effective in preventing cataracts in hyperglycemic animals.

Inhibitory effect of lycopene on cataract development in galactosemic rats.

This study investigated the effect of antioxidants on cataract formation in galactosemic rats. Two antioxicants were compared: lycopene, a carotenoid derived from tomato, and butylated hydroxytoluene (BHT), a known antioxidant substance. The control group was fed with galactose 30%. The experimental groups received, in addition to galactose 30%, either lycopene 0.8% or BHT 0.2%. Cataractogenesis was evaluated by the incidence of cataract, grading of cataract, histology of the lenses, aldose reductase (AR) activity, protein levels, and reduced glutathione (GSH) contents in the lens. In both experiemtal groups: 1) the incidence and grading of cataract were lower, 2) the protein levels and GSH content were higher, and 3) the AR was decreased compared to the control group. In conclusion, "natural antioxidants" such as lycopene derived from tomato have a similar effect as BHT in delaying cataractogenesis in rats.