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Insulin-mimetic and insulin-sensitizing activities of a pentacyclic triterpenoid insulin receptor activator

Title
Insulin-mimetic and insulin-sensitizing activities of a pentacyclic triterpenoid insulin receptor activator
Authors
Jung S.H.Ha Y.J.Shim E.K.Choi S.Y.Jin J.L.Yun-Choi H.S.Lee J.R.
Ewha Authors
이종란
SCOPUS Author ID
이종란scopus
Issue Date
2007
Journal Title
Biochemical Journal
ISSN
0264-6021JCR Link
Citation
vol. 403, no. 2, pp. 243 - 250
Indexed
SCI; SCIE; SCOPUS WOS scopus
Abstract
Five pentacyclic triterpenoids isolated from Campsis grandiflora were tested for insulin-mimetic and insulin-sensitizing activity. The compounds enhanced the activity of insulin on tyrosine phosphorylation of the IR (insulin receptor) β-subunit in CHO/IR (Chinese-hamster ovary cells expressing human IR). Among the compounds tested, CG7 (ursolic acid) showed the greatest enhancement and CG11 (myrianthic acid) the least. We characterized the effect of CG7 further, and showed that it acted as an effective insulin-mimetic agent at doses above 50 μg/ml and as an insulin-sensitizer at doses as low as 1 μg/ml. Additional experiments showed that CG7 increased the number of IRs that were activated by insulin. This indicates that a major mechanism by which CG7 enhances total IR auto-phosphorylation is by promoting the tyrosine phosphorylation of additional IRs. CG7 not only potentiated insulin-mediated signalling (tyrosine phosphorylation of the IR β-subunit, phosphorylation of Akt and glycogen synthase kinase-3β), but also enhanced the effect of insulin on translocation of glucose transporter 4 in a classical insulin-sensitive cell line, 3T3-L1 adipocytes. The results of the present study demonstrate that a specific pentacyclic triterpenoid, CG7, exerts an insulin-sensitizing effect as an IR activator in CHO/IR cells and adipocytes. The enhancement of insulin activity by CG7 may be useful for developing a new class of specific IR activators for treatment of Type 1 and Type 2 diabetes. © 2007 Biochemical Society.
DOI
10.1042/BJ20061123
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자연과학대학 > 생명과학전공 > Journal papers
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