tailieunhanh - PTP1B inhibitory flavonols from Orthosiphon stamineus Benth

From the alcoholic extract of the aerial parts of Orthosiphon stamineus Benth., three flavonols have been isolated. Their chemical structures were elucidated to be 5,7,3’,4’-tetramethylquercetin (1), 3’-hydroxy-3,5,7,4’- tetramethoxyflavone (2), and 3,5-dihydroxy-7,3',4'-trimethoxyflavone (3), by combining spectroscopic data and physicochemical data analyses (including IR, UV, NMR and MS). | Vietnam Journal of Chemistry, International Edition, 55(5): 652-656, 2017 DOI: PTP1B inhibitory flavonols from Orthosiphon stamineus Benth. Nguyen Phi Hung1,2, Hoang Duc Thuan3,4, Do Huu Nghi1, Vu Quoc Trung3*, Pham Quoc Long1 1 Institute of Natural Products Chemistry, Vietnam Academy of Science and Technology (VAST) 2 Graduate University of Science and Technology, VAST 3 4 Hanoi National University of Education Hanoi Training School for Educational Officers Received 6 June 2017; Accepted for Publication 20 October 2017 Abstract From the alcoholic extract of the aerial parts of Orthosiphon stamineus Benth., three flavonols have been isolated. Their chemical structures were elucidated to be 5,7,3’,4’-tetramethylquercetin (1), 3’-hydroxy-3,5,7,4’tetramethoxyflavone (2), and 3,5-dihydroxy-7,3',4'-trimethoxyflavone (3), by combining spectroscopic data and physicochemical data analyses (including IR, UV, NMR and MS). Compounds 1-3 exhibited potential PTP1B inhibitory activities with IC50 values of ±, ±, and ± µM, respectively. The positive control, ursolic acid, showed an IC50 value of ± µM in this assay. Keywords. Orthosiphon stamineus Benth., PTP1B inhibitor, flavonol, Cat’s whiskers, flavonoid. 1. INTRODUCTION Type 2 diabetes (T2D), or noninsulin-dependent diabetes mellitus, is the most common type accounting for approximately 90 % of the total cases among the three types of diabetes [1]. This type is characterized by a resistance to insulin, a peptide hormone produced by β-cells in the pancreas, which is responsible for glucose homeostasis [2, 3]. The insulin signaling pathway is negatively regulated by protein tyrosine phosphatases, most notably, protein tyrosine phosphatase 1B (PTP1B) [3]. The PTP1B over-expression inhibited the increased expression of insulin in insulin-resistant states [4], while PTP1B knockout mice display increased insulin sensitivity and show lower weight gain when .