Petrosin from Petrosia seriata

Petrosin-A and -B, two new bis-Quinolizidine Alkaloids from the Sponge Petrosia seriata. Braekman, J. C. Daloze, D Defay, N. and Zimmerman Bull. Soc. Chim. Belg. 1984, 93, 941. 

From the methanolic extract of sun-dried specimens of the sponge Petrosia seriata Braekman et al. 194) isolated a novel type of bis-quinolizidine alkaloid, the ichthyotoxic petrosin (312), and determined its structure by X-ray diffraction. 312, which contains a C-16 macrocycle, was toxic to the fish Lebistes reticulatus (LD = 50mg/L). Later,... 

Petrosines A and B, which were isolated in 1982 from the Papua New Guinea species Petrosia seriata, are symmetrical macrocycles with two quinolizidines (Braekman, Daloze, and Macedo De Abreu, 1982 Braekman et al, 1984). The presence of substituents in the quinoUzidine or 1-oxaquinolizidine rings implies the existence of numerous conformers, most of which were found later in Australian and Japanese Xestospongia as enantiomers or in racemic mixtures. 

---