Structures and antimicrobial activity of peniophorin A and B, two polyacetylenic antibiotics from Peniophora affinis Burt.

Two polyacetylenic antibiotics, peniophorin A and B, have been isolated from a strain of Peniophora affinis. Both have antibacterial and antifungal activity, but B is 3 to 20 times more active than A. Gram-positive cocci and a strain of Proteus vulgaris were especially susceptible to these two antibiotics. Both peniophorins contained an aromatic ring; B was an acid, and A was neutral. Peniophorin B was shown to be 2-(1-oxo-2,4-pentadiynl)phenyl acetic acid. The structure of A was only partially elucidated; it is suspected to be 6-[2-(1-oxo-2,4-pentadiynl)phenyl]5-methoxy-3-oxo-4-hexene-1-ol.