Lycosquarrines A-R, Alkaloids from .

Eighteen new alkaloids, lycosquarrines A-R (-), and eight known alkaloids were isolated from the aerial parts of . Compounds - and , identified from natural sources for the first time, are uncommon lycopodine-type alkaloids with β-oriented H-4. Pentacyclic and represent the first examples of 5,12- and 5,11-epoxy alkaloids, respectively, and an epoxide-opening cyclization reaction is suggested to be a key step in their biosynthesis. Compound possesses the same carbon skeleton as carinatine A (), which was previously reported as a unique alkaloid with a 5/6/6/6 ring system. X-ray crystallographic data analysis was used to determine the absolute configuration of , leading to the establishment of the absolute configuration of by comparison of the ECD spectra. An anti-acetylcholinesterase activity assay showed that and exhibited inhibitory activities with IC values of 4.2 and 2.1 μM, respectively.