Discovery of Novel Stilbene-Containing Nicotinamide Derivatives as Potential SDHIs against Rhizoctonia solani and Sclerotinia sclerotiorum.

Novel Pyrazole-4-carboxamide Derivatives with a Tetrahydroquinoline Skeleton: Promising SDHIs for the Control of Rhizoctonia solani.

Findings suggested that compound 6m might be a potent candidate as a succinate dehydrogenase inhibitor (SDHI) against R. solani with strong protective and curative effects even at 50 μg/mL.

Discovery of Thiram-Inspired Thiocarbamate Derivatives as Novel Laccase Inhibitors against Sclerotium rolfsii

Peanut stem rot, caused by the soil-borne pathogen Sclerotium rolfsii, poses a significant threat to global peanut production and results in substantial yield losses. A series of thiocarbamate derivatives were synthesized and evaluated against ten phytopathogenic fungi. Over 50% showed broad-spectrum fungicidal activity at 40 mg/L. Notably, compound b6 exhibited superior activity against S. rolfsii (EC50 = 0.75 mg/L), surpassing Thiram (EC50 = 0.91 mg/L). In vivo assays confirmed robust protective and curative efficacies on peanut seedlings. b6 also demonstrated potent laccase inhibition (IC50 = 0.064 mmol/L), significantly outperforming l-cysteine (IC50 = 0.551 mmol/L) and PMDD-5Y (IC50 = 0.326 mmol/L). Mechanistic studies revealed that b6 disrupts fungal cell membrane integrity and induces intracellular ROS accumulation. Overall, b6 represents a promising antifungal lead compound for designing novel laccase inhibitor-based fungicides.

Antifungal mechanism of eudesmane sesquiterpenoid glycosides from the fruits of Pittosporum kweichowense against Sclerotinia sclerotiorum.

BACKGROUND Sclerotinia stem rot (SSR), caused by Sclerotinia sclerotiorum (Lib.) de Bary, is among the most destructive crop diseases worldwide. This study aimed to identify novel antifungal agents from Pittosporum kweichowense and elucidate their mechanisms against this pathogen. RESULTS Six eudesmane-type sesquiterpenoid glycoside esters (ESGEs) were isolated from the fruit of P. kweichowense, including four new compounds pitkweifrucosides A-D (1-4), and two known analogs (5-6). Their structures were established by spectroscopic analyses and comparison with authentic samples. Compound 5 (Pitsubcoside H, PS-H) showed potent antifungal activity against S. sclerotiorum with a median effective concentration of 38.61 μg mL-1. At 100 μg mL-1, PS-H inhibited mycelial growth and reduced sclerotial formation by 75.00%. It also delayed sclerotial germination at early stages and decreased oxalic acid production by 73.08%. TEM observation confirmed disruption of cellular integrity. Transcriptomic and metabolomic analyses further revealed that PS-H exerts antifungal effects primarily through perturbation of amino acid metabolism and ribosomal function. CONCLUSION This study demonstrates that PS-H exhibits significant antifungal activity against S. sclerotiorum via disruption of key metabolic pathways. These findings provide a solid basis for developing this compound as a sustainable, low-toxicity alternative to conventional fungicides. © 2026 Society of Chemical Industry.

Six undescribed sesquiterpenoids from the endophytic fungus Irpex lacteus: Their antifungal and inhibitory activities against Setaria viridis.

Twelve sesquiterpenoids, comprising six new compounds (1-6) and six known compounds (7-12), were isolated from the endophytic fungus Irpex lacteus derived from Castanea mollissima Blume. Structural elucidation was achieved through a combination of spectroscopy, ECD calculations, and X-ray crystallography. These compounds exhibited diverse antifungal activities against Fusarium equiseti. Compound 7 displayed antifungal activity against F. equiseti with a MIC of 2 μg/mL, which was comparable to the positive control nystatin (1 μg/mL). Compared with all the tested compounds, compound 3 at 60 μg/mL exerted the strongest inhibitory effect on the shoot growth of Setaria viridis seedlings, with an inhibition rate of 82%. For the root growth of S. viridis seedlings, compound 9 at 30 μg/mL showed the highest inhibitory activity, reaching an inhibition rate of 94%. These findings highlight the metabolic diversity of I. lacteus and provide valuable insights into the development of antifungal agents against F. equiseti and herbicides against S. viridis.

Identification of Syringic Hydrazide Derivatives as Promising Succinate Dehydrogenase Inhibitors with Superior Antifungal and Anti-Oomycete Efficacy for Ensuring Food Safety

Fungal diseases remain a major constraint on global crop production, driving the search for fungicides with broader efficacy and improved selectivity. Confronting the dual challenges of structural rigidity and declining antifungal performance in conventional succinate dehydrogenase inhibitors (SDHIs), this study developed novel syringic acid derivatives. Notably, W11 exhibited remarkable broad-spectrum potency against eight phytopathogenic fungi and two oomycete species, with EC50 values of 0.679, 0.424, and 0.384 μg/mL against Gibberella zeae, Alternaria solani, and Colletotrichum fructicola, respectively. This activity significantly surpassed that of the commercial fungicide boscalid (EC50 >25.0, 0.826, and >25.0 μg/mL). Interestingly, W11 exhibited excellent succinate dehydrogenase inhibitory activity, causing a marked increase in intracellular reactive oxygen species (ROS), severe mitochondrial damage, and ultimately cell death. Overall, this work presents a structure-driven strategy that expands the antifungal spectrum of SDHIs and offers a promising scaffold for developing eco-friendly agrochemicals to address both limited antifungal activity and emerging oomycete challenges in sustainable agriculture.

New naphthoquinone derivatives from the marine-derived fungus Fusarium solani as potential fungicidal candidates against Lasiodiplodia theobromae