Six Unusual Meroterpenoids from the Leaves of Psidium guajava L. and Their PTP1B Inhibitory Activities.

Six unusual meroterpenoids, psidiguajadiol A-J ( 1 - 6 ), and three known meroterpenoids ( 7 - 9 ) were isolated from the leaves of Psidium guajava L. Compounds 2 - 6 represent the first examples of 6/8-formyl-5,7-dihydroxy-4-phenylchromane-coupled sesquiterpenoids. The structures of the undescribed compounds, including their absolute configurations, were elucidated by spectroscopic analyses, X-ray diffraction, and computational calculations. Compounds 3 , 4 , and 6 exhibited inhibitory activities against PTP1B with IC 50 values of 9.83, 18.52, and 16.87 μM, respectively. In light of these findings, we performed molecular docking studies to predict their inhibition mechanisms at the atomic level.