Cationic gemini compounds with antifungal activity and wood preservation potentiality

Abstract

Three gemini compounds were synthesized and characterized in the search of an alternative eco-friendly wood preservative. Synthesis was carried out from N,N-dimethylamines and 2-O-acetyl-1,3- dichloropropane as linker molecule. All the synthesized molecules were adequately purified and characterized by TLC, GC, FT-IR and NMR. Their tensioactive properties were determined. All three efficiently lowered the surface tension in aqueous solutions with critical micelle concentrations ranging from 0.53 to 1.34 mM. Their antifungal activities were evaluated from a broth dilution test against four yeasts and two filamentous fungi and were compared to commercially available references: Fluconazole and TCMTB (2-thiocyanomethylthiobenzothiazole). All gemini compounds displayed good antifungal activity; particularly, the gemini derived from N,N-dimethyldodecylamine, with even better performance than Fluconazole against Saccharomyces cerevisiae, Aspergillus niger and Alternaria sp., and than TCMTB against the last one. The environmental impact of the gemini compound that showed the highest antifungal activity was analyzed through ecotoxicity tests, using Chlorella vulgaris and Daphnia magna as model organisms. It was several orders of magnitude less toxic than TCMTB. Finally, wood preservation efficacy studies were carried out on pine (Pinus ponderosa) samples. Results demonstrated accomplished resistance against brown rot fungi, comparable to a widespread commercial hydrosoluble preservative.