Inhibition of protein tyrosine phosphatase 1B by prenylated isoflavonoids isolated from the stem bark of Erythrina addisoniae.

Eun Young Bae, Minkyun Na, Dieudonné Njamen, Joseph Tanyi Mbafor, Zacharias Tanee Fomum, Long Cui, Dong Ho Choung, Bo Yeon Kim, Won Keun Oh, Jong Seog Ahn

Korea Research Institute of Bioscience and Biotechnology, Yuseong-gu, Daejeon, Korea.

Planta medica 2006 Aug

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It has been suggested that protein tyrosine phosphatase 1B (PTP1B) inhibitors might be a therapeutic target for the treatment of type 2 diabetes and obesity. A bioassay-guided phytochemical study of the EtOAc extract of the stem bark of Erythrina addisoniae (Leguminosae) resulted in the identification of a new PTP1B inhibitory compound, 5,2',4'-trihydroxy-6-(gamma,gamma-dimethylallyl)-2''',2'''-dimethyldihydropyrano[5''',6''']isoflavanone ( 6), along with five known prenylated isoflavonoids, orientanol E ( 1), senegalensin ( 2), warangalone ( 3), warangalone 4'-methyl ether ( 4) and 2,3-dihydroauriculatin ( 5). Compounds 1, 5 and 6 inhibited PTP1B with IC (50) values ranging from 2.6 +/- 0.5 to 10.1 +/- 0.3 microM. Our results indicate that hydroxylation at both 2'- and 4'-positions in the B-ring and cyclization between a hydroxy group at C-7 and one of the prenyl groups at C-6 or C-8 in the A-ring may be important for activity. Thus, compounds 5 and 6 could be a new class of natural PTP1B inhibitors.

Citation

Eun Young Bae, Minkyun Na, Dieudonné Njamen, Joseph Tanyi Mbafor, Zacharias Tanee Fomum, Long Cui, Dong Ho Choung, Bo Yeon Kim, Won Keun Oh, Jong Seog Ahn. Inhibition of protein tyrosine phosphatase 1B by prenylated isoflavonoids isolated from the stem bark of Erythrina addisoniae. Planta medica. 2006 Aug;72(10):945-8