Context/objectives: The effects of methanol extract of aerial parts of Phyllanthus niruri L. (Euphorbiaceae), an antidiabetic herb, on glucose absorption and storage in diabetes were studied to elucidate the mechanisms of blood glucose lowering and glycemic control in diabetes.
Methods: The effect of chronic oral administration of the extract on glycemic control was evaluated in alloxan diabetic rats using blood glucose lowering and post-prandial glucose suppression activities as well as effects on hemoglobin glycation and body weight. Effects on glucose mobilization and storage were assessed using the weight and glycogen content of liver isolated from treated diabetic rats, while in vitro inhibition of α-amylase and α-glucosidase enzyme activities were used as indices of effect on glucose absorption.
Results: Results showed that the extract lowered blood glucose, suppressed postprandial rise in blood glucose following a glucose meal, reduced hemoglobin glycation and increased absolute and relative weights as well as glycogen content of liver in diabetic rats. Treatment with the extract also ameliorated the decrease in body weights caused by the diabetic disease. In vitro, the extract inhibited α-amylase (IC₅₀: 2.15 ± 0.1 mg/mL) and α-glucosidase (IC₅₀: 0.2 ± 0.02 mg/mL) activities.
Discussion and conclusion: These findings suggest that aerial parts of P. niruri may owe their blood glucose lowering properties to inhibition of glucose absorption and enhancement of glucose storage.