Novel 4,5-seco-Abietane-Type Diterpenes from Salvia prattii

Abstract Eight new 4,5-seco-abietane-type diterpenes, salpratones B–I, along with two analogues, featuring diverse 6/5/6, 6/6/6, 6/6/7, and 6/6/8 ring systems, were isolated from Salvia prattii. Notably, salpratone B is the first example of a 4,5;13,14-bis-seco-abietane diterpene characteristic with a rare rearranged 6/5/6 tricyclic core skeleton. Their structures were determined by comprehensive NMR spectroscopy, single-crystal X-ray diffraction, and electronic circular dichroism. Moreover, salpratones B–D were resolved into optically pure enantiomers. Partial diterpenes were evaluated for their in vitro anticoagulant activities. While salpratones B, E, F can weakly prolong the clotting times of human plasma in the activated partial thromboplastin time (APTT) assays with concentrations of 100 μM, showing no appreciable anticoagulant activities.