Pyrrolidinoindoline alkaloids from Selaginella moellendorfii

Eight new pyrrolidinoindoline Alkaloids (1-8) were isolated from the whole plant of Selaginella moellendorfii. Their structures were determined by mass spectrometry, 1D and 2D NMR spectroscopy, and chemical interconversions. These Alkaloids have a 3-carboxybut-2-enyl group at C-3a and two methyl groups at N-8. The possible biogenetic route from selaginellic acid (1) to neoselaginellic acid (6) was postulated and chemically mimicked. Tautomerization between 6 and 6a was observed. Selected compounds were evaluated for Antibacterial, cytotoxic, and acetylcholinesterase inhibitory activities.