Ke Zhao,Shiwei Sun,Hui Wang,Lin Wang,Guoqing Qin,Jiahe Fan,Mengru Guo,Wei Wang
α -Glucosidase plays an important role in catalyzing the hydrolytic cleavage of disaccharides into monosaccharides. In this study, a phytochemical investigation of the potential α -glucosidase inhibitory fraction from the aerial parts of Euonymus fortunei led to the isolation and identification of two new tetracyclic triterpenoids , fortunenones A and B ( 1 – 2 ), together with 11 known triterpenoids ( 3 – 13 ). Fortunenones A and B are rare C 32 triterpenoids possessing a 24,24-dimethyl group. The partial isolated compounds were evaluated their effects on α -glucosidase, of which echinochlorin D ( 5 ), lupenone ( 7 ), wilforlide B ( 12 ), and wilforlide A ( 13 ) exhibited remarkable inhibitory effects with the half inhibitory concentration ranged from 207.2 × 10 −6 M to 388.3 × 10 −6 M compared with the positive control, acarbose. An enzyme kinetics analysis by Lineweaver-Burk plots revealed that the inhibition types of the four active compounds were all mixed inhibition. Molecular docking further revealed that hydrophobic interactions and hydrogen bonds play an important role in the inhibition of α -glucosidase activity. Our results demonstrate the potential of E. fortunei extract and its constituents to inhibit α -glucosidase.
Leaf spot disease has recently emerged on Euonymus fortunei in Shanxi Province, China, causing noticeable foliar lesions and reducing ornamental value. The causal agent was identified as Alternaria alternata based on morphological characteristics and multilocus phylogenetic analysis using five loci (Alt a1, gapdh, RPB2, ITS, and OPA10-2). Biological characterization showed that mycelial growth was optimal at 27 ℃ on oatmeal agar, whereas conidial germination was favored under alkaline conditions (pH 9.0). The pathogen was sensitive to NaCl stress but showed no significant response to different light regimes. In vitro fungicide sensitivity assays revealed marked differences in inhibitory efficacy between mycelial growth and conidial germination, indicating strong developmental stage-dependent responses. Certain fungicide mixtures exhibited enhanced inhibitory effects compared with single compounds, suggesting potential synergistic interactions. Microscopic observations further revealed fungicide-induced morphological abnormalities, including hyphae swelling, roughened surfaces, reduced sporulation, and deformation of conidial germ tubes. This study represents the first report of A. alternata causing leaf spot disease on E. fortunei in China and provides a basis for understanding pathogen biology and developing effective chemical management strategies for this emerging ornamental disease.
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