Laetiporic acid, a new polyene pigment from the wood-rotting basidiomycete Laetiporus sulphureus (Polyporales, Fungi)

A new pigment, laetiporic acid, has been isolated from fruit-bodies of the wood-rotting fungus Laetiporus sulphureus (sulfur shelf). Structure elucidation by application of extensive 2D NMR techniques permitted its identification as a polyene of non-isoprenoid origin. Laetiporic acid, which represents the main pigment in L. sulphureus basidiocarps, bears an unprecedented decaene skeleton as part of its chromophore and, interestingly, contains double bonds with a stable cis configuration.