Inhibitory activity of dihydrosanguinarine and dihydrochelerythrine against phytopathogenic fungi.

The antifungal activities of dihydrosanguinarine and dihydrochelerythrine, isolated from the leaves of Macleaya microcarpa, were evaluated on 12 plant pathogenic fungi; the two compounds exhibited the highest antifungal activity against Botrytis cinerea Pers. Among the 11 tested plant pathogenic fungi in vitro, the two compounds showed the highest antifungal activity against B. cinerea Pers, with 95.16% and 98.32% mycelial growth inhibition at 50 µg mL⁻¹, respectively. In addition, the two compounds inhibited spore germination in vitro in a concentration-dependent manner. They also showed potent protective and curative effects against Erysiphe graminis and B. cinerea in vivo. This is the first report on the antifungal activity of dihydrosanguinarine and dihydrochelerythrine against pathogenic plant fungi.