Ruellia tuberosa L. is a folk remedy, which is used in the treatment of diabetes mellitus, antiinflammation and diuretic agent. However, its α-glucosidase inhibitory activity has not been investigated so far. In the present study, the antidiabetic activitiesof the hexane, ethyl acetate and methanol fraction of crude ethanolic extract of this plant were investigated. Our preliminary results showed that the crude ethanol extract as well as ethyl acetate and methanol fractions of Ruellia tuberosa showed α-glucosidase inhibitory activity with IC50 of 15.84, 4.73 and 8.27 μg/ml, respectively. From the ethyl acetate extract of whole plant of Ruellia tuberosa, four compounds, including rutin (1), syringaresinol (2), catechin (3) and pulmatin (4) were isolated and identified by column chromatography. Their structures were elucidated by spectroscopic method including MS, 1D and 2D- NMR and comparison with the literature values.
Keywords: Ruellia tuberosa L., flavonoid, anthraquinone glycoside, α-glucosidase inhibitory activities