Enzymatic production of atranorin: a component of the oak moss absolute by immobilized lichen cells

Synopsis Cells of the lichen, Evernia prunastri, immobilized in calcium alginate were able to produce the depside atranorin from acetate. The synthesis of the depside was enhanced by molecular oxygen and NADH. This enhancement suggested the participation of an oxidase and an alcohol dehydrogenase to produce an aldehyde-substituted phenolic acid, hematommic acid, as the most probable precursor of atranorin. The participation of both enzymes was confirmed by loading immobilized cells with sodium azide, an inhibitor of several metallo-oxidases, and pyrazole, an inhibitor of alcohol dehydrogenase, which impeded atranorin production and accumulated β-methyl orsellinate (after azide loading) or its alcohol derivative (after pirazole treatment). Resume Les cellules du lichen Evernia prunastri, immobilisees dans l'alginate de calcium, produisent le depside atranorine a partir d'acetate. La synthese de cet depside fut activee par l'oxygene et le NADH. Cette activation suggere la participation d'une oxidase et d'une alcool deshydrogenase pour produire un phenol contenant une fonction aldehyde, l'acide hematommique, le plus probable precurseur de l'atranorine. La participation de ces deux enzymes fut confirmee par addition, aux cellules immobilisees, d'azide de sodium, un inhibiteur des metallo-oxidases, et de pyrazole, un inhibiteur de l'alcool dehydrogenase. Tous les deux empechent la production de l'atranorine et occasionnent l'accumulation du β-methyl orsellinate (azide de sodium) ou de l'alcool (pyrazole).