Cytotoxic fatty acid from Pleurocybella porrigens.

The new conjugated ketonic fatty acid, porrigenic acid (1), was isolated as a cytotoxic constituent of Pleurocybella porrigens. The structure of 1 was elucidated using spectroscopic methods including 1D and 2D NMR and MS. The absolute stereochemistry of 1 was determined by application of the exciton chirality method. Compound 1 exhibited cytotoxic activity against myeloma THP-1 cells, but did not show any significant toxicity against B16F1 melanoma. This is the first report of the isolation and structural elucidation of the new cytotoxic constituent porrigenic acid (1) from the edible mushroom P. porrigens.