Theaflavin Enriched Black Tea Extract Alleviates Diabetic Nephropathy by Suppressing Hyperglycaemia-Mediated Oxidative Stress and Inflammation in Streptozotocin-Induced Rats

Background: Diabetic Nephropathy (DN), a microvascular complication of diabetes has been a significant health issue globally. However, theaflavin enriched black tea extract (BTE-TF) could restrain DN. Objective: The main objective of this exploration was to elucidate the effect of BTE-TF on DN, though the underlying mechanism remains unclear and requires further investigation. Methods: The tea leaves were fermented to get black tea extract. Total phenolic content and HPLC were carried out to determine the phenolic content and theaflavin in the extract. Streptozotocin induced diabetic rats were treated with 100, 200, and 400 mg/kg/day BTE-TF extract for 12 weeks. Biochemical parameters like blood glucose, creatinine, Blood Urea Nitrogen (BUN), triglyceride and antioxidant parameters of kidney tissue were measured. Histology, immunohistochemistry and TUNEL assay were performed to observe the effect of the extract with comparison to the standard drug (Metformin 200mg/kg/day). Result: Treated animals exhibited reduced blood glucose levels, blood urea nitrogen (BUN), creatinine, and serum triglycerides. Further, BTE-TF restored the histological alterations in the kidney. Chronic hyperglycaemia resulted in a significant increase in oxidative stress and pro-inflammatory cytokines of NF-kβ pathway. BTE-TF attenuated oxidative stress (p<0.01), inflammation (p<0.05) and apoptosis (p<0.05). Conclusion: This study suggests that BTE-TF exerts a protective role against diabetes-induced renal injury by ameliorating oxidative stress, inflammation, and apoptosis.