Design, Synthesis, and Antifungal Evaluation of Novel Formononetin-Benzothiazole Hybrids with Preliminary Mechanistic Insights.

Synthesis and antifungal activity evaluation of flavonol derivatives containing an imidazolidinone moiety.

Design, synthesis and bioactivity of benzoxazinone-containing formononetin derivatives.

BACKGROUND Phytopathogens have long compromised the yield and quality of crops worldwide, and the overuse of conventional synthetic pesticides has engendered a series of ecological and environmental issues. Consequently, the development of low-toxicity, high-efficacy and environmentally benign pesticides has become an urgent imperative. RESULTS Using the natural product formononetin as starting material, a series of formononetin derivatives bearing benzoxazinone moiety were designed and synthesized, and their in vitro antifungal activities against 10 phytopathogenic fungi were evaluated. The results revealed that J21 exhibited the most potent inhibitory effect against Phomopsis sp. (Ps), with a median effective concentration (EC50) of 7.58 μg mL-1, which was significantly superior to that of the commercial fungicide azoxystrobin (Az, 30.32 μg mL-1). In in vivo antifungal assays, at a concentration of 200 μg mL-1 J21 displayed curative and protective activities of 56.1% and 66.8% against kiwifruit soft rot, respectively, outperforming Az (47.8% and 63.3%). Mechanistic investigations demonstrated that J21 induces morphological deformation and damage to hyphae, disrupts cell membrane integrity, triggers oxidative stress and interferes with normal physiological metabolism of the pathogen. Density functional theory (DFT) calculations further indicated that J21 possesses favorable electronic structural properties. CONCLUSION J21 displays promising antifungal activity and represents a potential lead compound for antifungal development. © 2026 Society of Chemical Industry.

Discovery of Novel Carbohydrazide-Containing Formononetin Derivatives as Potential Broad-Spectrum Antifungal Agents.

A series of formononetin derivatives containing carbohydrate structures were designed and synthesized, and the in vitro antifungal activities of these compounds were evaluated. Among them, X4 displayed the most potent antifungal activity against Rhizoctonia solani (Rs), with an EC50 value of 0.58 μg/mL, outperforming azoxystrobin (Az, EC50 = 6.87 μg/mL), fluopyram (Fl, EC50 = 47.74 μg/mL), and boscalid (BC, EC50 = 1.02 μg/mL). In vivo antifungal assays conducted on rice leaves and kiwifruit demonstrated that X4 displayed satisfactory protective and curative effects. Meanwhile, X4 exhibited excellent inhibitory activity against both sclerotium formation and germination of Rs. As verified by scanning electron microscopy (SEM), fluorescence microscopy (FM), and MDA assays, X4 inhibited fungal growth by disrupting the integrity of the mycelial cell membrane and inducing lipid peroxidation. Molecular docking experiments combined with SDH activity assays indicated that X4 engages in favorable interactions with SDH.

Design, Synthesis, and Antifungal Activity of Thiazolidinedione Derivatives Incorporating Thioamide and Piperidine Moieties.

A series of thiazolidinedione derivatives containing thioamide and piperidine moieties were designed, synthesized, and evaluated for antifungal activity against plant pathogenic fungi. Several compounds exhibited potent antifungal activity, among which Z17 was the most active against Rhizoctonia solani (EC50 = 1.8 μg/mL), with substantially greater activity than azoxystrobin (Az; EC50 = 42.6 μg/mL). Physiological analyses indicated that Z17 disrupted membrane integrity and cellular energy metabolism, as reflected by increased malondialdehyde levels and decreased pyruvate kinase activity and pyruvate content. Density functional theory calculations, molecular docking, and molecular dynamics simulations suggested that Z17 forms favorable interactions with the cytochrome bc1 complex. Preliminary safety assessments showed no significant effects on rice seed germination or earthworm viability. These findings suggest Z17 as a promising lead for the development of antifungal agents against crop pathogens.

Design and Synthesis of Novel Trifluoromethylpyrimidinamine Derivatives Bearing an Amide Moiety for Targeting Plant Pathogens

A series of novel trifluoromethylpyrimidinamine derivatives containing an amide moiety were designed and synthesized. The antimicrobial activity of the title compounds against various plant-pathogenic fungi and bacteria was evaluated. Among them, the EC50 of compound 7i against Pseudomonas syringae pv actinidiae (Psa) was 11.38 μg/mL, which was superior to that of the positive control thiodiazole copper (TC, 85.69 μg/mL), indicating excellent inhibitory activity. In vivo anti-Psa activity assays revealed that at 200 μg/mL, compound 7i conferred protective and curative effects of 69.10% and 65.16% on kiwifruit leaves, respectively, both of which were superior to those of TC (40.77% and 54.47%). Further mechanistic studies demonstrated that compound 7i disrupts cell integrity, induces leakage of intracellular proteins and nucleic acids, reduces extracellular polysaccharide production, and promotes the generation of reactive oxygen species. Additionally, molecular docking simulations of compound 7i with the FtsZ protein further confirmed its superior activity. The potent antibacterial activity of compound 7i supports its potential application in the prevention and control of plant disease.

Design, Synthesis, and Antifungal Activity of Trifluoromethylpyridine-Containing Amide Derivatives.

A series of trifluoromethylpyridine-containing amide derivatives were designed and synthesized. All compounds were evaluated in vitro for antifungal activity against representative plant-pathogenic fungi. Bioassay results indicated that compounds 10o, 10t, 10x, and 10ad exhibited pronounced in vitro antifungal activities. Notably, 10ad showed an EC50 of 1.22 μg/mL against Botrytis cinerea (Bc), which was superior to those of the commercial fungicides azoxystrobin (12.84 μg/mL), procymidone (4.87 μg/mL), and Pyrimethanil (3.52 μg/mL). Compound 10ad also demonstrated in vivo antifungal efficacy against Bc, with protective and curative activities above 60% at 400 μg/mL, again surpassing these commercial fungicides. As demonstrated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), molecular docking, and enzyme activity assays, mechanistic studies suggest that 10ad disrupts organelle integrity, inhibits mycelial growth, and modulates antioxidant enzyme activities. These results indicate that 10ad is a promising lead for the development of novel crop-protection fungicides.