Moringa Oleifera Leaf Increases Insulin Secretion after Single Dose Administration: A Preliminary Study in Healthy Subjects

Herbal medicine has long been used as an alternative medicine for treatment of type 2 diabetes mellitus (T2DM). Recently, Moringa oleifera (MO or ma-rum in Thai) leaf has been widely used in T2DM patients. Several studies in diabetes rat model have shown that MO had effect on glucose metabolism. However study in humans is lacking. Examine effects of MO on plasma glucose and insulin secretion. Ten healthy volunteers were enrolled in this study (mean age 29 ± 5 years; BMI 20.6 ± 1.5 kg/m2; FPG 81 ± 5 mg/dl). After an overnight fast and every two weeks, subjects received an oral dose of MO at increasing dosages of 0, 1, 2, and 4 g. Plasma glucose (PG) and insulin were collected at baseline and at 0.5, 1, 1.5, 2, 4, and 6 hours after each MO dosage administration. Insulin secretion rate was measured using area under the curve (AUC) of insulin and AUC of insulin/glucose ratio. After doses of 0, 1, 2, and 4 g MO, mean plasma insulin increased (2.3 ± 0.9, 2.7 ± 1.0, 3.3 ± 1.4, and 4.1 ± 1.7 μU/ml, respectively) despite there being no differences in mean PG (77 ± 6, 78 ± 5, 79 ± 6, and 79 ± 5 mg/dl, respectively). AUC of insulin was greater after high-dose MO (4 g) than after baseline or low-dose MO capsule (1 g) (24.0 ± 3.5 vs. 14.5 ± 1.8 or 16.1 ± 2.0, respectively; p = 0.03), while there was no difference in AUC of glucose. Accordingly, insulin secretion rate represented by AUC of insulin/glucose ratio after high-dose MO was significantly increased by 74% (P = 0.041), as compared with that of baseline. We concluded that high-dose (4 g) MO leaf powder capsules significantly increased insulin secretion in healthy subjects. These results suggest that MO leaf may be a potential agent in the treatment of type 2 diabetes. Further studies of MO in patients with T2DM are needed.