AROMATIC ALKALOIDS FROM THE MARINE SPONGE CHELONAPLYSILLA SP

Four novel alkaloids derived from tryptophan and tyrosine subunits have been isolated from the marine sponge Chelonaplysilla sp. collected from a marine lake in Palau. The structures of chelonin A (3), chelonin B (4), bromochelonin B (5), and chelonin C (6) were determined by interpretation of spectral data and chemical conversions. Chelonin A (3) and C (6) are the first natural products incorporating a 2,6-disubstituted morpholine ring. Chelonin A (3), chelonin B (4), and bromochelonin B (5) exhibited antimicrobial activity against Bacillus subtilis, while chelonin A (3) showed in vivo antiinflammatory activity.