Showing papers on "Aphanamixis published in 2021"

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

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

Diverse prieurianin-type limonoids with oxygen-bridged caged skeletons from two Aphanamixis species: discovery and biomimetic conversion

Abstract: The spatially close and highly reactive ester appendages through the opening of A and B rings of prieurianin-type limonoids would further rearrange into diverse ring system via oxygen-bridges or new C–C bonds. In our current research, two limonoids with an unprecedented 7/6/5 tricyclic skeleton (1) and 2,6-dioxabicyclo[3.2.2]nonan-3-one caged ring A system (2), along with eight other new ones (3–10) were obtained from Aphanamixis polystachya and Aphanamixis sinensis, and the structure of 1 was confirmed by X-ray crystallographic diffraction. Meanwhile, a reliable solution based on biomimetic alkaline hydrolysis to build new oxygen-bridges via OH-1 was established to resolve the difficulties in the structural elucidation of prieurianin limonoids with broad or missing NMR signals and applied for the determination of 9 and 10. Moreover, the potential of Dieckmann reaction as a key biosynthetic step in the formation of C-3/C-6 bonds in the aphanamolide-type backbone was verified by chemical conversions of 13–16. These findings provided new ideas and perspectives for structural elucidation and chemical communication of prieurianin-type limonoids.

Antifungal Activity of an Endophytic Fungus Aspergillus versicolor DYSJ3 from Aphanamixis grandifolia Blume against Colletotrichum musae

Abstract: An endophytic fungus strain DYSJ3 was isolated from a stem of Aphanamixis grandifolia Blume, which was identified as Aspergillus versicolor based on the morphological characteristics, internal tran...