Alkaloids From Lycopodiastrum Casuarinoides And Their Bioactivities

Lycopodiastrum casuarinoid.es (Spring) Holub (family Lycopodiaceae) is commonly known as’Shu-Jin-Cao’in Chinese, which has been used as a folk medicine for relaxing the tendons and stimulating the blood circulation. Ten new lycodine-type alkaloids, named casuarinines A-J (1-10), along with eight known analogues, were isolated from the whole plant of L. casuarinoides.The new structures were established by extensive spectroscopic methods (including ID,2D NMR, circular dichroism) and by some chemical transformations. Casuarinines A-D (1-4) and J (10) are common lycodine alkaloids possessing four connected six-membered rings, while tricyclic casuarinines E-H (5-8) are the piperidine ring cleavage products. In particular, casuarinine I (9) has an unprecedented five-membered tetrahydropyrrole ring instead of the piperidine ring. A plausible biosynthetic pathway to9is proposed.Among the compounds reported, casuarinine H (8) exhibited significant neuroprotective effect against hydrogen peroxide (H2O2)-induced neuronal cell damage in human neuroblastoma SH-SY5Y cells, while casuarinines C (3) and I (9) were found to show moderate inhibitory activity against acetylcholinesterase (AChE).