Five Lycopodium alkaloids featuring novel C 17 N 2 (1 and 2), C 29 N 3 (3 and 4), and C 15 N 2 (5) skeletons were isolated from Lycopodium japonicum. Compound 1 is the first natural product containing a 3-aza[3.3.3]propellane motif. The structures of these compounds were elucidated by spectroscopic analysis, Xray crystallography, and computational methods. Compounds 1 and 3−5 significantly inhibited TGF-β 1 -induced fibronectin deposition in HK-2 cells at a nontoxic concentration of 20 μM.

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The structural revision of four Stemona alkaloids from Stemona tuberosa is reported. The misassignment of the tuberostemonine O structure (1) was recognized when a new alkaloid, tuberostemonine P, was isolated and unambiguously assigned structure 1 in this work. Reinvestigation of the spectroscopic data and NMR calculations led to the revised structure 1a for tuberostemonine O. The structural misassignment of dehydrocroomine A as 2 was corrected by reinterpreting the X-ray crystal structure, which was consistent with 2a. The structural reassignments of dehydrocroomine B (3 to 3a) and dehydrocroomine (4 to 4a) were confirmed by X-ray crystallography and NMR calculations, respectively.