| Literature DB >> 17059169 |
Sohee Kim1, Minkyun Na, Hyuncheol Oh, Junpil Jang, Cheon Bae Sohn, Bo Yeon Kim, Won Keun Oh, Jong Seog Ahn.
Abstract
Protein tyrosine phosphatase 1B (PTP1B) is considered as a therapeutic target for the treatment of diabetes and obesity. In our preliminary screening study, a MeOH extract of the aerial part of Siegesbeckia glabrescens was found to inhibit PTP1B activity at 30 microg/mL. Bioassay-guided fractionation led to the isolation of two active diterpenes, ent-16betaH, 17-isobutyryloxy-kauran-19-oic acid (1) and ent-16betaH, 17-acetoxy-18-isobutyryloxy-kauran-19-oic acid (2), along with ent- 16betaH, 17-hydroxykauran-19-oic acid (3). Compounds 1 and 2 inhibited the PTP1B activity with IC50 values of 8.7 +/- 0.9 and 30.6 +/- 2.1 microM, respectively. Kinetic studies suggest that both 1 and 2 are non-competitive inhibitors of PTP1B. However, compound 3 substituted with a hydroxyl group at C-17 in kaurane-type showed no inhibitory effects towards PTP1B.Entities:
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Year: 2006 PMID： 17059169 DOI： 10.1080/14756360600741560
Source DB: PubMed Journal: J Enzyme Inhib Med Chem ISSN： 1475-6366 Impact factor: 5.051