title: Inhibition of protein tyrosine phosphatase 1B by lupeol and lupenone isolated from Sorbus commixta.
abstract: Protein tyrosine phosphatase 1B (PTP1B) appears to be an attractive target for the development of new drugs for type 2 diabetes and obesity. In our preliminary test, a MeOH extract of the stem barks of Sorbus commixta Hedl. (Rosaceae) showed strong PTP1B inhibitory activity. Bioassay-guided fractionation of the MeOH extract resulted in the isolation of two lupane-type triterpenes, lupenone (1) and lupeol (2). Compounds 1 and 2 inhibited PTP1B with IC(50) values of 13.7 +/- 2.1 and 5.6 +/- 0.9 microM, respectively. Kinetic studies revealed that both the compounds 1 and 2 are non-competitive inhibitors of PTP1B that decrease V(max) values with no effect on K(m) values.
authors: College of Pharmacy, Yeungnam University, Gyeongsan, Gyeongbuk 712-749, Korea.
authors: Minkyun
authors: M
authors: Na
authors: Bo Yeon
authors: BY
authors: Kim
authors: Hiroyuki
authors: H
authors: Osada
authors: Jong Seog
authors: JS
authors: Ahn
mesh_terms: D001667:Binding, Competitive; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000302:isolation & purification / Q000494:pharmacology*; D015394:Molecular Structure; D053978:Pentacyclic Triterpenes / Q000494:pharmacology*; D024301:Plant Bark / Q000737:chemistry; D010936:Plant Extracts / Q000737:chemistry*; D018547:Plant Stems / Q000737:chemistry; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1 / Q000037:antagonists & inhibitors*; D031994:Sorbus / Q000737:chemistry*; D014315:Triterpenes / Q000494:pharmacology*; D000094042:Lupanes
chemical_list: D004791:Enzyme Inhibitors; D053978:Pentacyclic Triterpenes; D010936:Plant Extracts; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D014315:Triterpenes; C470592:lupenone; D000094042:Lupanes; C010480:lupeol