Four new β-carboline alkaloids isolated from two Okinawan marine sponges of Xestospongia sp. and Haliclona sp.)

Four new β-carboline alkaloids isolated from two Okinawan marine sponges of Xestospongia sp. and Haliclona sp.) 6-Hydroxymanzamine A and 3,4-Dihydromanzamine A, New Alkaloids from the Okinawan Marine Sponge Amphimedon sp. 6-Hydroxymanzamine A and 3,4-Dihydromanzamine A, New Alkaloids from the Okinawan Marine Sponge Amphimedon sp. Zamamidines A and B, New Manzamine Alkaloids from the Sponge Amphimedon Species Two New Alkaloids from Xestospongia sp., a New Caledonian Sponge Two New Alkaloids from Xestospongia sp., a New Caledonian Sponge Ma'eganedin A, a new manzamine alkaloid from Amphimedon sponge Ircinals A and B from the Okinawan marine sponge Ircinia sp.: plausible biogenetic precursors of manzamine alkaloids A new β-carboline alkaloid isolated from the marine sponge Hyrtios erecta A New Manzamine Congener from Marine Sponge Amphimedon sp.