Antidiabetic and wound healing properties of selected Kenyan tea cultivars

Abstract

Diabetes mellitus is a metabolic disorder of multiple etiology, characterized by chronic hyperglycemia with disturbances of carbohydrate, fat and protein metabolism resulting from defects in insulin secretion, insulin action or both. It is associated with significant morbidity and mortality due to cardiovascular complications as a result of imbalance in lipid metabolism. Diabetic foot ulcers (DFUs) are estimated to occur in 15% of all patients with diabetes and precede 84% of all diabetes-related lower leg amputations. Tea is rich in bioactive molecules that may play a role in modulating carbohydrate metabolism and wound healing. The study sought to determine if tea can prevent or reverse metabolic disturbances induced by diabetes, including occurrence of diabetic wounds. Green and black teas were processed from four different cultivars and assayed for their total monomeric anthocyanin content, total polyphenols content, catechin profiles and theaflavin profiles. Teas rich in anthocyanins, epigallocatechin gallate (EGCG), theaflavins (TF) and total polyphenols were chosen for assay in an animal model. An alloxan induced diabetic mouse model was used to study the anti diabetic potential of processed tea. Hyperglycaemia resulting from alloxan administration caused a significant (p<0.05) increase in blood glucose and cholesterol levels as well as low body weights and packed cell volume (PCV). Oral administration of tea helped alleviate these complications. Blood glucose and cholesterol levels were lowered in treated groups compared to controls. PCV levels increased while body weights declined in both diabetic and healthy mice on tea. Anthocyanin rich tea produced more beneficial effects compared to other teas. Wound healing, angiogenesis and wound repair was augmented in anthocyanin treated group when compared to the placebo group, findings well documented by histological investigations. Results of this study demonstrate that hyperglycaemia and deranged carbohydrate metabolism plays a significant role in diabetic complications including artheriosclerosis and delayed wound healing. Moreover, these results demonstrate beneficial effects of tea in wound healing and diabetic complications.