Fluopyram

Fluopyram is an orally active succinate dehydrogenase inhibitor, antifungal and nematicide. Fluopyram inhibits succinate dehydrogenase activity, activates CAR/PXR nuclear receptors, and increases caspase-3, TNF-α and NF-κB. Fluopyram inhibits the growth of F. virguliforme, Botrytis cinerea and Alternaria solani with EC₅₀ values of 3.35, 5.389 and 0.244 µg/mL, respectively. Fluopyram induces liver and thyroid tumor formation. Fluopyram is nephrotoxic and embryotoxic^{[1][2][3][4][5][6][7][8]}. IC50 & Target:Succinate dehydrogenase, Fungal^[1] In Vitro: Fluopyram (0-126 μM; 48 h) inhibits the motility of Meloidogyne incognita and Heterodera schachtii second-stage infective juveniles (J2) in a concentration-dependent manner^[1].
Fluopyram (96 h) shows moderate toxicity to zebrafish embryos, with a LC₅₀ of 4.375 mg/L and inhibits their skeletal development^[4].
Fluopyram (0.01-0.25 mg/L; 24 h) causes damage to the growth, locomotion behavior, feeding, lifespan and reproduction of C. elegans, induces oxidative stress, and affects the expression of genes associated with oxidative stress, intestinal damage, and cell apoptosis^[5].
Fluopyram nanoparticles (FLU-NS, mean particle size 366.8 nm) show higher antifungal activity against Botrytis cinerea and Alternaria solani than fluopyram micron-sized solid formulation (FLU-MS, mean particle size 2.99 µm) and fluopyram wettable powder (FLU-WP, mean particle size 10.16 µm), with an EC₅₀ value of 5.389 and 0.244 µg/mL against B. cinerea and A. solani respectively^[6].
In Vivo: Fluopyram (30-1500 ppm; p.o., in diet; daily; 3-28 days) activates CAR/PXR nuclear receptors in female Wistar rats, increases hepatocellular proliferation, and leads to liver tumor formation in a dose-dependent manner^[2].
Fluopyram (100-300 mg/kg/day (equivalent to 750-2000 ppm dietary concentrations); p.o.; daily; 3-28 days) activates hepatic CAR/PXR nuclear receptors in male C57BL/6J mice, increases thyroid-stimulating hormone (TSH) secretion, and leads to thyroid follicular cell (TFC) adenomas in a dose-dependent manner^[3].
Fluopyram (0.5-2 mg/kg; s.c.; every 2 days; 21 days) causes dose-dependent increased toxicity in mouse kidney tissues, leading to histopathological changes and increased positive staining of caspase-3, TNF-α, and NF-κB^[7].