Pinocembrin Isolated from Nigerian Propolis Prevents Elevation of Cytokines Implicated in the Aetiology of Diabetic Retinopathy in Rat Models of Diabetes Mellitus.

Propolis, a resin produced by bees-, contains the flavonoid compound pinocembrin, which shows promise for antioxidant and anti-inflammatory applications, though its therapeutic potential remains underexplored. Diabetic retinopathy, a common complication of diabetes, involves retinal inflammation and vascular damage. Previous research indicates that Nigerian propolis may have anti-hyperglycemic effects and the ability to lower glycosylated hemoglobin levels. This study evaluated the protective effects of pinocembrin, extracted from Nigerian propolis, against diabetic retinopathy in a streptozotocin-induced rat model. Diabetes was induced in male Sprague-Dawley rats through a single intraperitoneal injection of streptozotocin, resulting in sustained hyperglycemia. The diabetic rats were then administered oral pinocembrin at a dose of 50 mg/kg daily for 8 weeks. Pinocembrin effectively mitigated the elevation of inflammatory mediators, including Interleukin-1 (IL-1), Interleukin-8 (IL-8) and Tumor Necrosis Factor-alpha (TNF-α), within the retinal tissues of the treated diabetic rats. Furthermore, pinocembrin enhanced levels of the antioxidant enzymes such as Superoxide Dismutase (SOD) and Glutathione Peroxidase (GSH-Px), and also improved glycemic control and glycosylated hemoglobin levels. The results indicate that pinocembrin possesses significant therapeutic potential for preventing or mitigating diabetic retinopathy. Its capacity to regulate inflammatory processes and strengthen antioxidant defenses underscores its potential as a treatment strategy for managing this vision-threatening complication associated with diabetes mellitus.