Antifungal activities of matrine and oxymatrine and their synergetic effects with chlorthalonil

Abstract

The EC50 values of matrine and oxymatrine against five forest pathogenic fungi (Fusarium oxysporum, Valsa pini, Cladosporium oxysporum, Sphaeropsis sapinea, Marssonina brunnea) were examined by bioassay methods. The results demonstrated that matrine and oxymatrine had strong inhibitory activities to the conidium germination of the tested fungi. The EC50 values of matrine for inhibiting the conidium germination of Marssonina brunnea, Cladosporium oxysporum, Sphaeropsis sapinea were 123 μg·mL−1, 272 μg·mL−1, 1133 μg·mL−1, respectively, and the EC50 values of oxymatrine for inhibiting the conidium germination of Fusarium oxysporum, Sphaeropsis sapinea were 532 μg·mL−1, 601 μg·mL−1, respectively. The hyphal growth of the fungi was also significantly inhibited by matrine and oxymatrine. The EC50 values of matrine inhibiting the conidium germination of Sphaeropsis spainea, Valsa pini, Fusarium oxysporum were 428 μg·mL−1, 535 μg·mL−1, 592 μg·mL−1, respectively. The EC50 values of oxymatrine inhibiting the conidium germination of Valsa pini, Fusarium oxysporum were 323, 618 μg·mL−1, respectively. In the synergetic tests the EC50 values of the mixtures of thiophanate methyl (or chlorthalonil) and matrine (or oxymatrine) were lower than 34 μg·mL−1 while their co-toxicity coefficients were significantly higher than 100. It indicated that the mixture of the alkaloids and the chemical had potential practical utilization in controlling certain forest fungal diseases.