Characterization and Antifungal Activity of Limonoid Constituents Isolated from Meliaceae Plants Melia dubia, Aphanamixis polystachya, and Swietenia macrophylla against Plant Pathogenic Fungi In Vitro

The plants of Meliaceae are native to tropical and subtropical regions as the Americas, west India, Southeast Asia, Southern China. Many species genera Khaya, Swietenia, Aphanamixis, Melia in this family known medicinal have biological activities such antiviral, antimicrobial, antifeeding, insecticidal, cytotoxic properties. objectives research characterize evaluate bioactive limonoids from several against phytopathogenic fungi. During search antifungal compounds Meliaceae, three methanol extracts dubia, Aphanamixis polystachya, Swietenia macrophylla were found suppress mycelial growth Nine isolated M. dubia (1–2), A. polystachya (3–5), S. (6–9) evaluated, for first time, their effectiveness nine fungi Fusarium oxysporum, Magnaporthe oryzae, Sclerotium rolfsii, Rhizoctonia solani, Alternaria spp., Botrytis cinerea, oomycetes Phytophthora species. Limonoids 2, 3, 6, 8 displayed a remarkable broad-spectrum activity all test rolfsii was highly sensitive four with IC50 values ranging 79.4 128.0 µg/mL. Notably, chisocheton compound G (3) khayanolide B (8) most potent exhibited dose-dependent Compounds 2 9 moderate oryzae. Our study results demonstrated discovery lead group application control fungal plant diseases.