Drychampones A-C: Three Meroterpenoids from Dryopteris championii.

Three novel sesquiterpenoid-based meroterpenoids, drychampones A-C (1-3, 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 1-3 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.