Investigation of medicinal plants from Madagascar against DPP-IV linked to type 2 diabetes

The Madagascarian plants which have been investigated in this study have been used as antidiabetic plants in traditional medicine. As the control of dipeptidyl peptidase IV (DPP-IV) activity is an important aspect in management of type 2 diabetes, the purpose of the present study was evaluation of DPP-IV inhibitory activity of medicinal plants from Madagascar. Ethyl acetate extracts were screened for DPP-IV inhibitory activity. High-resolution DPP-IV inhibition profiling was employed for identification of active peaks. Preparative-scale HPLC was performed for isolation, and elucidation of the compound structure was done by high-performance liquid chromatography-high-resolution mass spectrometry-solid-phase extraction-nuclear magnetic resonance spectroscopy, HPLC-HRMS-SPE-NMR. Only the ethyl acetate extract of Antidesma madagascariense Lam. leaves showed DPP-IV inhibitory activity with an IC50 value of 79.2 ± 2.8 μg/mL. Amentoflavone, which was identified for the first time in A. madagascariense, was identified as DPP-IV inhibitor, with an IC50 value of 3.9 ± 0.5 μM. This is the first report on DPP-IV inhibition by amentoflavone. Thus, this plant is a promising species for use in herbal medicine as a DPP-IV inhibitor.