Synergistic effect of the association of Prosopis juliflora polyphenolic extractives with tebuconazole on the growth inhibition of brown and white rot fungi: a solution to increase the naturality and safety of wood preservation treatment

The antifungal effect of catechin and extractives from Prosopis juliflora was studied against one white rot fungus, Trametes versicolor (TV), and one brown rot fungus, Rhodonia placenta (PP). The extractives from Prosopis julilfora were crude mesquitol and pure mesquitol. Tebuconazole was used in this study as a known fungicide against the two named fungi. Wood protection using fungicides can be harmful to the environment and toxic to animals and plants. To solve this toxicity issue, fungicides can be mixed with natural extractives or secondary metabolites to act synergistically as biocides or wood preservatives. In this study, 1000 ppm and 5000 ppm of crude mesquitol, pure mesquitol and catechin had a very good growth inhibition against Trametes versicolor and Rhodonia placenta. Thus, the concentrations were used to assess their synergistic response when mixed with lower inhibitory concentration of tebuconazole. The results showed that there was antagonistic effect in a combination of 0.5 ppm Tebuconazole with 1000 ppm crude mesquitol and pure mesquitol for Rhodonia placenta and 0.5 ppm tebuconazole with 1000 ppm pure mesquitol in Trametes versicolor. There was no effect for 0.1 ppm tebuconazole combination with 1000 ppm pure mesquitol for Rhodonia placenta. However, there existed synergistic response in all other remaining combinations of 1000 ppm/5000 ppm of the samples with 0.1 ppm/0.5 ppm tebuconazole. This data suggests that a combination of polyphenols (catechin and extractives) with tebuconazoles can be useful sources for preparation of fungicides and wood preservatives for agricultural use and wood durability respectively.