A new alkaloid glycoside and antifungal metabolites from the aerial parts of Argemone mexicana Linn. collected in Vietnam

A new benzophenanthridine alkaloid glycoside (1), named nitrotyrasanguinarinoside, together with twelve known compounds (2 −13), was isolated from the dichloromethane extract of the aerial parts of Argemone mexicana Linn. Their structures were elucidated using IR, HR-ESI-MS, 1D and 2D NMR, and ECD spectroscopy, as well as by comparison with the published data. The dichloromethane extract exhibited in vivo antifungal activity against Colletotrichum coccodes with 80% inhibition at a concentration of 3000 µg/mL. Five benzophenanthridine alkaloids (1 − 5) inhibited four phytopathogenic fungi in vitro, including Alternaria brassicicola, Cladosporium cucumerinum, Magnaporthe oryzae, and Phytophthora infestans, with MIC values ranging from 0.016 to 0.987 mM. Notably, the new compound 1 showed strong activity against all four tested fungi, with MIC values ranging from 0.016 to 0.063 mM.