Note
In the course of our continuing search for novel antimicrobial
agents, we have isolated a new antibacterial
compound Sch 575948 (1) along with a known alkaloid
ptilomycalin A (2) from a marine sponge Ptilocaulis
spiculifer (or Crambe crambe). Sch 575948 was identified
as a bicyclic bis-guanidine type of alkaloid, a homolog of
crambcscin A (or crambine A (3)), identified as a major
component of the homolog complex.