Objective and Background: Diabetic retinopathy is amongst the most common microvascular
complications associated with diabetes. Controlling blood glucose level alone cannot manage diabetes
associated complications. Thus, mechanisms that additionally prevent diabetes associated complications
are the need of the hour, driving the researchers towards herbal therapies. Terminalia catappa
is renowned for its anti-inflammatory, antioxidant, anti-hyperglycemic and anti-angiogenic activity.
The current study explores the effect of Terminalia catappa fruit extract on streptozotocin-induced
diabetic retinopathy in rats.
Methods: Streptozotocin-induced chronic diabetic rat model was utilized in the study. The hydroalcoholic
fruit extract of T. catappa in 20mg/kg, 30mg/kg and 40mg/kg dose and standard anti-diabetic
drug, glibenclamide (10mg/kg) was given orally. Retinopathy was evaluated by monitoring lenticular,
fundus images and measuring arteriole and venule tortuosity index. Oxidative, angiogenic and inflammatory
biomarkers were assessed at the 12th week in the retinal homogenate. Histopathological
changes in the retina were also examined. Data was analyzed using one-way Repeated Measure
ANOVA followed by the Mann-Whitney test.
Results: The hydro-alcoholic fruit extract of T. catappa significantly decreased blood glucose
(p<0.001) in a dose-dependent manner in diabetic rats. Cataract lens was observed in all experimental
groups and became clear (grade 0) with 40mg/kg and with 40mg/kg along with glibenclamide at the
eighth and sixth week, respectively. The hydro-alcoholic fruit extract in all three doses significantly
reduced (p<0.01) arteriole and venule tortuosity in diabetic rats.
T. catappa in all three doses in diabetic rats showed a modulatory effect in oxidative, angiogenic and
Conclusion: T. catappa reverses diabetes-induced retinopathy by anti-hyperglycemic, anti-oxidant,
anti-angiogenic and anti-inflammatory actions, and thus has a potential to be used in diabetes-induced