Antifungal activity of alkyl and heterocyclic aza-derivatives of gossypol as well as their complexes with NaClO 4 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, 1H and 13C 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.