Novel filicinic acid-based meroterpenoids with antiproliferative activity against prostate cancer PC-3 cells from Dryopteris wallichiana

Filicinic acid-based meroterpenoids (1‒9) with four kinds of skeletons were isolated from Dryopteris wallichiana. Compounds 1–4 represent the first examples of filicinic acid-ent-kaurane diterpene hybrids. Compounds 5‒6 are the rare hybrids of filicinic acid and carotane-type sesquiterpene. Compound 7 is an unusual rearranged filicinic acid-carotane-type sesquiterpene meroterpenoid. A plausible biosynthetic pathway for compounds 1−9 is proposed. Compounds 5, 6, (+)/(‒)-8, and (+)/(‒)-9 were validated to display anti-proliferative activity against PC-3 cells based on virtual screening, molecular docking and in vitro bioassay.