Developed beverage from roselle calyx and selected fruits modulates β-cell function, improves insulin sensitivity, and attenuates hyperlipidaemia in diabetic rats

The aim of this study is to report the antidiabetic properties of a beverage developed from roselle calyx and selected fruits in male albino rats. The beverage was designed to contain 30% pawpaw (Carica papaya L.), 10% grapefruit (Citrus paradisi), 20% guava leaves (Psidium guajava L.) and 40% roselle calyx aqueous extracts. Four groups of five rats each were acclimatized on pelletized mouse chow for seven days, after which diabetes was induced by a single ip injection of alloxan in all groups except group 1, which served as control. Group 2 served as negative control while groups 3 and 4 were treated with the beverage at 2.5 and 5 ml/kg bw respectively. Food intake, body weight, and blood glucose levels were monitored. They were sacrificed by cervical dislocation after a 2 week treatment. Blood serum was analysed to evaluate insulin levels, β cell function, insulin resistance and lipid profile. Histological studies were carried out on pancreatic tissues. Treatment with both doses of the beverage led to a significant reduction (p < 0.05) in blood glucose, total cholesterol triglyceride, LDL and increased HDL levels. It also improved serum insulin levels, β cell function, reduced insulin resistance and restored pancreatic beta cells compared to the diabetic group. These antidiabetic properties may be as a consequence of modulation of the β-cell function, reduction of insulin resistance and preservation/restoration of β-cell integrity. However, treatment with the single dose showed signs of hyperinsulinaemia.