Damipipecolin and damituricin, novel bioactive bromopyrrole alkaloids from the Mediterranean sponge Axinella damicornis.

Abstract Two new bromopyrrole alkaloids, damipipecolin ( 1 ) and damituricin ( 2 ), have been isolated from the Mediterranean sponge Axinella damicornis , and their structures established through spectroscopic methods. Compounds 1 and 2 extend the structural variety of the so far known pyrrole alkaloids; in these compounds, the 4-bromopyrrole 2-carboxylic acid is directly condensed with a non-protein cyclic α-amino acid, the (2 R , 4 R )- trans -4-hydroxypipecolic acid and (2 R , 4 R )- cis - N , N ′-dimethyl-4-hydroxyproline ( d -turicine) in 1 and 2 , respectively. Compounds 1 and 2 were found to display a modulating effect of the serotonin receptor activity in vitro.