Biosynthesis of 13-Hydroperoxylinoleate, l0-Oxo-8-decenoic Acid, and l-Octen-3-ol from Linoleic Acid by a Mycelial-Pellet Homogenate of Pleurotus pulmonarius

The compounds 13-hydroperoxy-cis-9,trans-11-octadecadienoic acid (13-HPOD) and 10-oxo-trans-8-decenoic acid (10-oxo-acid) were quantified by HPLC and identified by FT-IR, GC, MS, and GC-MS as the major metabolites associated with the enzymatic cleavage of linoleic acid to 1-octen-3-ol by a homogenate of pellets of the mushroom Pleurotus pulmonarius grown in submerged culture. Whereas 13-HPOD was absent at linoleic acid concentrations below 1 mM, it was the major product of the enzymatic oxidation at linoleic acid concentrations above 1 mM. Nonetheless, 13-HPOD was found not to be the precursor of l-octen-3-ol when supplied as the substrate instead of linoleic acid. Instead, 50% of it was reduced to 13-hydroxy-cis-9,trans-11-octadecadienoic acid. However, in the presence of linoleic acid, no hydroxy acid was detected, suggesting that linoleic acid itself inhibited 13-HPOD reduction. It appears, therefore, that 13-HPOD accumulation takes place in parallel with l-octen-3-ol and 10-oxo-acid biosynthesis.