Antifungal activity of alkyl and heterocyclic aza-derivatives of gossypol as well as their complexes with NaClO4 against Fusarium oxysporum f. sp. lupini.

ABSTRACT

Eight alkyl and six heterocyclic aza-derivatives of gossypol (2-15) have been synthesized using gossypol (1) extracted from Gossypium Herbaceum cottonseeds. The ability of gossypol aza-derivatives to form complexes with NaClO(4) has been investigated by electrospray ionisation (ESI) mass spectra recorded in the positive and negative ion detection modes. The gossypol aza-derivatives have been characterized by FT-IR, (1)H and (13)C NMR spectroscopic methods and subsequently tested for their antifungal properties against Fusarium oxysporum. Four alkyl aza-derivatives (2-5), present in the enamine-enamine tautomeric form, have shown activity comparable or higher than that of gossypol against this fungus. To improve the antifungal activity the complexes of the most active compounds 2-5 with NaClO(4) were prepared. Complexes of 2 and 5 with NaClO(4) have shown antifungal activity higher than that of the uncomplexed compounds.