Natural PTP1B Inhibitors from broussonetia papyrifera

Two new compounds, 8-(1,1-dimethylallyl)-5′-(3-methylbut-2-enyl)-3′,4′,5,7-tetrahydroxyflanvonol (1), 3′-(3-methylbut-2-enyl)-3′,4′,7-trihydroxyflavane (2) and three known compounds 3,3′,4′,5,7-pentahydroxyflavone (3), uralenol (4), broussochalcone A (5) were isolated from the roots of Broussonetia papyrifera, and their structures determined by spectroscopic methods. Compounds 1, 3, 4 and 5 significantly show the inhibitory activities against the PTP1B enzyme.