Anti-diabetic effects of a theaflavin-enriched black tea extract in the obese ZDF rat model

Effects of a theaflavin-enriched black tea extract (BTE) against type 2 diabetes (T2D) were analyzed using the obese ZDF model. ZDF rats were hyperglycemic, dyslipidemic and express pro-inflammatory markers. BTE was well tolerated and caused an elevation of fasted and fed glucose as well as lower glucose tolerance in contrast to hypoglycemic effects by metformin. However, the BTE group showed decreased levels of LDL and triacylglycerols which corresponded to an increase in free fatty acids. Positive effects against dyslipidemia of BTE corresponded to a significant decrease in weight gain. The impact on inflammatory pathways was analyzed by expression analysis of inflammatory mediators in whole blood and epididymal adipose tissue using TaqMan PCR and ELISA. Whole blood analysis revealed a significant down-regulation of ICAM-1 and TNF-α, whereas IL-4, IL-6, IL-10, IL-13 and IFN-γ were elevated to higher levels as compared to ibuprofen. In adipose tissue, BTE treatment induced an upregulation of COX-2 and IL-6. Thus, BTE treatment showed strong effects against systemic inflammation and caused a reduction of weight gain with positive effects against dyslipidemia. The complexity of signaling pathways leading to complications in diabetes suggest a treatment of BTE in combination with antidiabetic therapeutics as promising strategy against T2D.

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

The Natural Products Journal ◽

10.2174/2210315510999200607182700 ◽

2020 ◽

Vol 10 ◽

Author(s):

Dhrubajyoti Sarkar ◽

Sekhar Kumar Bose ◽

Tania Chakraborty ◽

Souvik Roy

Keyword(s):

Oxidative Stress ◽

Diabetic Nephropathy ◽

Blood Glucose ◽

Blood Urea Nitrogen ◽

Phenolic Content ◽

Black Tea ◽

Total Phenolic ◽

Urea Nitrogen ◽

Black Tea Extract ◽

Tea Extract

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.

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Development and Characterization of Functional Starch-Based Films Incorporating Free or Microencapsulated Spent Black Tea Extract

Molecules ◽

10.3390/molecules26133898 ◽

2021 ◽

Vol 26 (13) ◽

pp. 3898

Author(s):

Surakshi Wimangika Rajapaksha ◽

Naoto Shimizu

Keyword(s):

Antioxidant Activity ◽

Lipid Oxidation ◽

Food Packaging ◽

Uv Light ◽

Antioxidant Properties ◽

Black Tea ◽

Wall Material ◽

Food Simulants ◽

Black Tea Extract ◽

Tea Extract

Antioxidant polyphenols in black tea residue are an underused source of bioactive compounds. Microencapsulation can turn them into a valuable functional ingredient for different food applications. This study investigated the potential of using spent black tea extract (SBT) as an active ingredient in food packaging. Free or microencapsulated forms of SBT, using a pectin–sodium caseinate mixture as a wall material, were incorporated in a cassava starch matrix and films developed by casting. The effect of incorporating SBT at different polyphenol contents (0.17% and 0.34%) on the structural, physical, and antioxidant properties of the films, the migration of active compounds into different food simulants and their performance at preventing lipid oxidation were evaluated. The results showed that adding free SBT modified the film structure by forming hydrogen bonds with starch, creating a less elastic film with antioxidant activity (173 and 587 µg(GAE)/g film). Incorporating microencapsulated SBT improved the mechanical properties of active films and preserved their antioxidant activity (276 and 627 µg(GAE)/g film). Encapsulates significantly enhanced the release of antioxidant polyphenols into both aqueous and fatty food simulants. Both types of active film exhibited better barrier properties against UV light and water vapour than the control starch film and delayed lipid oxidation up to 35 d. This study revealed that starch film incorporating microencapsulated SBT can be used as a functional food packaging to protect fatty foods from oxidation.

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