(+)-Crinatusin A1 (Compound (+)- 4) is a chalcone-monoterpene hybrid, which can be isolated from Cleistocalyx operculatus. (+)-Crinatusin A1 is an inhibitor for protein tyrosine phosphatase 1B ( PTP1B ) with IC 50 of 0.9 μM. (+)-Crinatusin A1 exhibits potential as an antidiabetic agent.