Investigation of Beneficial Role of Pimpinella Anisum Essential Oil in Cataract

Abstract

Cataract is clouding of the lens that can impair the vision. It begins when the lenticular protein gets precipitated which may be due to overproduction of oxygen-free radicals, disorders (diabetes, blood pressure), smoking, ultraviolet radiation, trauma, etc. The mechanism behind the age related cataract is post-translational changes in the proteins like α-crystallins. The diabetic cataract is caused by the involvement of polyol pathway in which aldose reductase enzyme regenerate sufficient amount of NADPH and inhibits the conversion of sorbitol to glucose using polyol dehydrogenase. It leads to increasing the amount of sorbitol in to the lens which is substantial enough to produce osmotic stress and hence cataract formation. Essential oil of Pimpinella anisum possess rich content of trans-anethole which possess good antioxidant property and also shows inhibitory action on aldose reductase enzyme.Purpose To evaluate the effect of Pimpinella anisum in senile cataract by using In vivo model of naphthalene and in vitro model of hydrogen peroxide induced oxidative stress. To evaluate the role of Pimpinella anisum in diabetic cataract by using In vitro assay of aldose reductase inhibitory activityMaterials and methods Phytochemical analysis Essential oil of Pimpinella anisum was evaluated for total phenolic and flavonoid content and qualitative confirmation by HPTLC for the presence of trans-anethole. In vivo naphthalene modelHealthy Sprague-Dawley rats were randomly divided into 7 groups (n=10) like normal control, treatment control, disease control, diseased treated with standard, and diseased treated with the drug. Cataracts were induced by oral administration of 1 g naphthalene/kg body weight/day with the treatment of essential oil of Pimpinella anisum with two different dose 0.5ml/kg/day and 1ml/kg/day for 9 weeks. The development of cataract was examined every week and at the end of 9 weeks, antioxidant parameters were performed. In vitro hydrogen peroxide induced cataract The Wistar rat lenses were isolated from posterior approach under sterile condition. The lenses were cultured in 24 well plates containing 1.5 ml of medium-199 media (without phenol red) with hydrogen peroxide 0.5 mM and pretreatment was given to the lens for 24 hours before induction to check the preventive action of the drug. The development of cataract was seen after 24 hours and antioxidant parameters were performed. In vitro aldose reductase activity Aldose reductase enzyme was prepared and used in a reaction mixture of phosphate buffer, NADPH, LiSO4 and D-xylose with treatment of different doses of Pimpinella anisum essential oil. The IC50 value of Aniseed oil was found for the inhibition of aldose reductase enzyme. Results Phytochemical analysis It showed that essential oil of Pimpinella anisum contains 91.875%w/v phenolic compounds, flavonoids 44%w/v. The presence of trans-anethole was confirmed by HPTLC. In vivo naphthalene model Cataract was not developed after 9 weeks by oral administration of 1 g naphthalene/kg. Also after performing antioxidant parameters, it showed no significant changes between normal control and disease control group. In vitro hydrogen peroxide induced cataractCataract was developed by 0.5mM hydrogen peroxide and it showed protective effect on standard, trans-anethole and aniseed oil lenses compared with the disease control lenses using stereoscopic images. The protective effect is confirmed by the improvement in the antioxidant parameters. In vitro aldose reductase activity IC50 value of Aniseed oil for aldose reductase inhibition was found to be 1.077μl/mlConclusion Our data suggests that aniseed oil and trans-anethole may be effective in preventing the development of senile cataract in the rat lens as shown by the improvement in the oxidative stress. It also shows significant inhibition of aldose reductase enzyme and thus may be helpful in diabetic cataract.