(±)-Salvicatone A: A Pair of C<sub>27</sub>-Meroterpenoid Enantiomers with Skeletons from the Roots and Rhizomes of <i>Salvia castanea</i> Diels f. <i>tomentosa</i> Stib
Dongdong Wang, Rui Zhang, Lian-Yu Tang, Guo-Qing Long, Hui Yan, Yong-Cheng Yang, Zifeng Guo, Yingying Zheng, Yong Wang, Jing‐Ming Jia, An‐Hua Wang
Abstract
(±)-Salvicatone A ( 1 ), a C 27 -meroterpenoid featuring a unique 6/6/6/6/6-pentacyclic carbon skeleton with a 7,8,8a,9,10,10a-hexahydropyren-1 ( 6H )-one motif, was isolated from the roots and rhizomes of Salvia castanea Diels f. tomentosa Stib. Its structure was characterized by comprehensive spectroscopic analyses along with computer-assisted structure elucidation, including ACD/structure elucidator and quantum chemical calculations with 1 H/ 13 C NMR and electronic circular dichroism. Biogenetically, compound 1 was constructed from decarboxylation following [4 + 2] Diels–Alder cycloaddition reaction between caffeic acid and miltirone analogue. Bioassays showed that (−)- 1 and (+)- 1 inhibited nitric oxide production in lipopolysaccharide-induced RAW264.7 macrophage cells with an IC 50 value of 6.48 ± 1.25 and 15.76 ± 5.55 μM, respectively. The structure-based virtual screening based on the pharmacophores in ePharmaLib, as well as the molecular docking and molecular dynamics simulations study, implied that (−)- 1 and (+)- 1 may potentially bind to retinoic acid receptor-related orphan receptor C to exert anti-inflammatory activities.