(±)-Salviakianes A–L, Twelve Pairs of Previously Undescribed Abietane Diterpenoid Enantiomers with Anti-inflammatory Activity from Salvia kiangsiensis

(±)-Salviakianes A–L (1–12), 12 pairs of previously undescribed 4,5-seco-20(10 → 5)-abeo-abietane diterpenoid enantiomers, were isolated from the whole plants of Salvia kiangsiensis. Among them, compounds 1–3 represent rare rearranged skeletons with an additional C-3–C-11 or C-4–C-11 linkage, while 4–12 features a highly oxidized C-1 to C-4 fragment, forming various oxacycles with C-11. Their structures were elucidated by a combination of spectroscopic analyses, ECD calculations, and X-ray diffraction, which also enabled revision of the structure of previously published de-O-ethylsalvonitin. All of the isolates were evaluated for anti-inflammatory activity in RAW264.7 cells, among which 1b exhibited the most potent activity with a micromolar IC50 value. A mechanistic study revealed that 1b exerted its anti-inflammatory effects primarily through suppression of the NF-κB signaling pathway.