Agelamadins C-E, Bromopyrrole Alkaloids Comprising Oroidin and 3-Hydroxykynurenine from a Marine Sponge Agelas sp.

Three structurally unique bromopyrrole alkaloids, agelamadins C-E (1-3) were isolated from a marine spone Agelas sp. Agelamadin C (1) possesses a hybrid structure of oroidin and 3-hydroxykynurenine connected through dihydro-1,4- oxazine moiety. Agelamadins D (2) and E (3) are a C-9/C-10 diasteromer and a 10-epimer of 1, respectively. The structures of 1-3 were elucidated on the basis of spectroscopic analysis as well as application of a PGME method and a TDDFT ECD calculation. Antimicrobial activity of 1-3 was evaluated.