Five new Lycopodium alkaloids from the aerial parts of Phlegmariurus henryi

A series of new Lycopodium alkaloids, namely 1-epi-malycorin A (1), 1-epi-17S-hydroxymalycorin A (2), 6α-hydroxyphlegmariurine A (3), 2S,4R-dihydroxyfawcettimine (4), and 16-hydroxylycodine (5), together with 24 known ones, have been isolated from the club moss Phlegmariurus henryi. The structures of the new compounds were determined by extensive spectroscopic analysis, including 1D and 2D NMR, as well as X-ray crystallographic analysis. Among them, the absolute configurations of 1, 2, and 4 and the structure of 3 were confirmed on the basis of the single-crystal X-ray diffraction analysis. 1-Epi-17S-hydroxymalycorin A (2) was a unique C19N-type Lycopodium alkaloid consisting of a serratinine skeleton with 1,2-propanediol unit. 2S,4R-dihydroxyfawcettimine (4) was a 2,4-dihydroxy derivative of fawcettimine. 16-Hydroxylycodine (5) was the oxidative product of lycodine with an unusual hydroxymethyl group at C-15. All new compounds were evaluated for in vitro acetylcholinesterase (AChE) inhibitory activity and cytotoxicity against four human cancer cell lines.

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