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

Abstract

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. Method: 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.

The Protective Effect of Theaflavins on the Kidney of Mice with Type II Diabetes Mellitus

“…This confirmed diabetic nephropathy [ 44 ]. High levels of UCr, SCr, Bun, and GFR indicated the severely impaired glomerular filtration potential in diabetic mice (MC) ( Figure 3 C–F), which was similar to the findings of Sarkar et al [ 11 ] and Mohan et al [ 31 ]. Additionally, images of HE-stained paraffin sections showed various pathological changes, such as glomerular mesangial expansion, glomerular hyaline, glomerular atrophy, and others, in the kidney tissue of diabetic mice (MC) ( Figure 4 C,D).…”

“…Findings from recent studies have demonstrated that TFs not only protect kidneys through antioxidant, anti-inflammatory, and anticancer pharmacological effects [ 6 , 7 , 8 , 9 ] but also improve T2DM, hypertension, and hyperlipidemia caused by obesity [ 10 ]. Meanwhile, Sarkar et al [ 11 ] showed that black tea extract rich in TFs exhibits a protective role against diabetic nephropathy in rats. However, even though the protective effects of TFs against diabetic nephropathy have been reported, the intrinsic molecular mechanism of action of theaflavins in diabetic nephropathy is not fully clear.…”

Antioxidant, Anti-Inflammatory, and Immunomodulatory Properties of Tea—The Positive Impact of Tea Consumption on Patients with Autoimmune Diabetes

“…A short-term exposure to oxidants increases the activity of endogenic antioxidants, which suggests activation of defensive mechanisms and adaptive cell response, but under the conditions of long-term oxidative stress, their activity is clearly lowered due to the expulsion of antioxidative metals from active enzyme centers [19,163]. Theaflavin administered to rats with induced diabetes lowered the levels of lipid peroxidation markers as well as other oxidative stress markers, while increasing the activity of antioxidative enzymes and exogenous non-enzymatic antioxidants [119,125,164]. During in vitro digestion of a water extract of matcha tea, polyphenols become more bioavailable and are characterized by higher antioxidative and antidiabetic activity when compared to sencha tea [165].…”