Discovery of Zoanthamine Alkaloids from with Antioxidant and Neuroprotective Activities.

Two novel alkaloids, zoanides A and B ( and ), 12 new zoanthamine-type alkaloids (-), together with two known compounds ( and ) were obtained from the zoantharian . Their structures and absolute configurations were established by extensive spectroscopic data, DP4+ probability calculation, and X-ray crystallographic analyses. Structurally, compound represents an unusual functionalized skeleton caused by oxidative cleavage; compound possesses an unprecedented 6/6/5/6/7-fused pentacyclic carbon skeleton. Additionally, the plausible biosynthetic pathways of and were proposed. All isolates were evaluated in vitro for neuroprotection. Among them, compounds , , , , and exhibited neuroprotection against paclitaxel-induced neurite damage without interfering with the anticancer effects of paclitaxel. Moreover, compounds and demonstrated moderate protective effects against oxaliplatin-induced oxidative stress overload without interfering with the anticancer effects of oxaliplatin.