Chemical Constituents of Morinda citrifolia Roots Exhibit Hypoglycemic Effects in Streptozotocin-Induced Diabetic Mice

The hypoglycemic effects of the chemical constituents of Morinda citrifolia roots was evaluated in streptozotocin (STZ)-induced diabetic mice. The CHCl3, EtOAc, n-BuOH and H2O soluble phases of the MeOH extract of M. citrifolia roots were administrated orally to STZ-induced diabetic mice. Only the n-BuOH soluble phase showed a significant reduction of the blood glucose levels. From the biologically active n-BuOH soluble phase, two iridoids and three anthraquinones were isolated as main constituents. These compounds were identified by spectroscopic analysis to be deacetylasperulosidic acid (1), asperulosidic acid (2), damnacanthol-3-O-β-D-primeveroside (3), lucidin 3-O-β-D-primeveroside (4) and morindone-6-O-β-D-primeveroside (5). 3 and 4 exhibited the hypoglycemic effects, which were anthraquinones with no substituents in one aromatic ring.