rk-682 and Diabetes-Mellitus--Type-2

According to the International Diabetes Federation, type 2 diabetes (T2D) has reached epidemic proportions, affecting more than 382 million people worldwide. Inhibition of protein tyrosine phosphatase-1B (PTP1B) and α-glucosidase is a recognized therapeutic approach for management of T2D and its associated complications. The lack of clinical drugs targeting PTP1B and side effects of the existing α-glucosidase drugs, emphasize the need for new drug leads for these T2D targets. In the present work, dual high-resolution PTP1B and α-glucosidase inhibition profiles of Eremophila gibbosa, E. glabra, and E. aff. drummondii "Kalgoorlie" were used for pinpointing α-glucosidase and/or PTP1B inhibitory constituents directly from the crude extracts. A subsequent targeted high-performance liquid chromatography-high-resolution mass spectrometry-solid-phase extraction-nuclear magnetic resonance spectroscopy (HPLC-HRMS-SPE-NMR) analysis and preparative-scale HPLC isolation led to identification of 21 metabolites from the three species, of which 16 were serrulatane-type diterpenoids (12 new) associated with either α-glucosidase and/or PTP1B inhibition. This is the first report of serrulatane-type diterpenoids as potential α-glucosidase and/or PTP1B inhibitors.

Topics: alpha-Glucosidases; Chromatography, High Pressure Liquid; Diabetes Mellitus, Type 2; Glycoside Hydrolase Inhibitors; Humans; Hypoglycemic Agents; Molecular Structure; Protein Tyrosine Phosphatase, Non-Receptor Type 1; Scrophulariaceae; Solid Phase Extraction

Two new 2-arylbenzofurans, glycybenzofuran (1) and cyclolicocoumarone (2), together with 10 known flavonoids including licocoumarone (3), glycyrrhisoflavone (4), glisoflavone (5), cycloglycyrrhisoflavone (6), isoliquiritigenin (7), licoflavone A (8), apigenin (9), isokaempferide (10), glycycoumarin (11), and isoglycycoumarin (12), were isolated from the roots of Glycyrrhiza uralensis and their structures were determined by extensive spectroscopic analyses. Compounds 1 and 5 showed significant protein tyrosine phosphatase-1B (PTP1B) inhibitory activity in vitro with the IC50 values of 25.5 and 27.9 microM, respectively. The structure-activity relationship indicated that the presence of prenyl group and ortho-hydroxy group is important for exhibiting the activity. Kinetic analysis indicated that compound 1 inhibits PTP1B by a competitive mode, whereas compound 5 by a mixed mode.

Topics: Diabetes Mellitus, Type 2; Flavonoids; Glycyrrhiza uralensis; Humans; Inhibitory Concentration 50; Plant Extracts; Plant Roots; Protein Tyrosine Phosphatase, Non-Receptor Type 1; Structure-Activity Relationship