Delta 6 desaturase inhibition. A novel mode of action of norflurazone

The herbicide Norflurazone was shown to be an inhibitor of fatty acid of the delta 6 desaturation system. Treating cultures of the microalgae Spirulina platensis or Monodus subterraneus with this herbicide brought about a reduction in the level of gamma-linolenic acid and in an increase in the level of linoleic acid. In Monodus, the increase in linoleic acid made it more available for omega 3 desaturation, resulting in an increase in the proportion of eicosapentaenoic acid. The proportion of arachidonic acid did not decrease albeit the drastic decrease in its precursor gamma-linolenic acid