Drychampones A–C: Three Meroterpenoids from Dryopteris championii

Three novel sesquiterpenoid-based meroterpenoids, drychampones A–C (13, respectively), were isolated from Dryopteris championii. Compounds 1 and 3 possessed a novel carbon skeleton which was constructed by an 11/6/6 ring system coupled with a pyronone moiety, and 13 were three racemates. Their structures and absolute configurations were elucidated by NMR, MS, and computational methods. The hypothetical biosynthetic pathways of these meroterpenoids and their antibacterial activities were also discussed.