Antifungal Activity of Oleoresin and Fractions of Pinus elliottii Engelm and Pinus tropicalis against Phytopathogens

Abstract

Microorganism resistance to the existing products is yet another difficulty that agriculturalists have to deal with. In this context, the search for new agricultural products that can fight phytopathogens has become increasingly important. Plants have played an important role in this process, because they can serve as a source of new compounds for drug discovery. Plants belonging to the genus Pinus produce an oleoresin that protects the plant against herbivores and pathogens. With a view to developing products that can combat fungal pathogens without harming the environment, this work aimed to evaluate the antifungal activity of the oleoresins and fractions of Pinus elliottii Engelm and Pinus tropicalis against phytopathogens. The methodology based on NCCLS M38-A standards aided antifungal activity assessment. The microdilution method helped to determine the Minimum Inhibitory Concentration (MIC) and Minimum Fungicidal Concentration (MFC). The oleoresins of P. elliottii and P. tropicalis afforded the most significant results—they displayed fungicidal activity against all the tested species. MIC values were promising, especially the MIC of the oleoresin of P. elliottii against S. rolfsii (1.95 μg · mL -1 ). The MIC values of the oleoresins of P. elliottii and P. tropicalis ranged from 1.95 to 1000 μg · mL -1 and from 31.25 to 250 μg · mL -1 , respectively. Fraction PT2 of P. tropicalis furnished the best results among all the assayed fractions: MIC values lay between 125 and 500 μg · mL -1 1. In conclusion, the oleoresin of P. tropicalis is a promising source of new antifungal agents for application in the treatment of phytopathogenic infections.