Ethalfluralin

Ethalfluralin is a dinitroaniline herbicide and microtubule (microtubule) inhibitor. It disrupts nuclear mitosis and cytokinesis in parasites by inhibiting spindle formation within the nucleus. Additionally, Ethalfluralin activates NF-κB and P38 MAPK phosphorylation, while inhibiting the PI3K/AKT signaling pathway, affecting mitochondrial function, and inducing apoptosis (apoptosis), endoplasmic reticulum stress, autophagy (autophagy), and ROS production. It has applications in research related to toxoplasmosis.

Ethalfluralin (2-20 μM; 48 h) reduces the viability of pLE and pTr cells. At 20 μM for 48 hours, it inhibits the expression of the proliferation marker PCNA in these cells. It also impairs migration after 4 hours at 20 μM. Ethalfluralin (5-20 μM; 48 h) induces cell cycle arrest in pLE and pTr cells, increasing the sub-G1 phase and reducing the S phase cell population. Furthermore, it promotes apoptotic cell death, increasing both late apoptotic cell populations in the two cell lines and early apoptotic cells in pTr. It reduces cytosolic and mitochondrial matrix calcium levels and disrupts the mitochondrial membrane potential in pLE and pTr cells. At 20 μM over 20 hours, it damages mitochondrial respiratory functions, reducing basal respiration, maximal respiration, spare respiratory capacity, and ATP production in pLE, and affects maximal respiration, spare capacity, and ATP generation in pTr. Additionally, ethalfluralin (20 μM; 24 h) decreases the mRNA expression of mitochondrial respiratory complex I-V subunit genes in pLE and pTr cells. It activates endoplasmic reticulum stress and autophagy pathways in pLE and pTr cells, increasing GRP78, phosphorylated eIF2α, GADD153, phosphorylated ULK1, phosphorylated P62, and promoting LC3B II/I conversion. Ethalfluralin (5-20 μM; 48 h) also activates P38 MAPK and NF-κB signaling pathways while inhibiting the PI3K/AKT pathway in these cells. At 20 μM for 48 hours, it impairs autophagic flux and reduces mitochondrial quality. Ethalfluralin strongly inhibits the replication of Toxoplasma gondii RH strain tachyzoites in human primary foreskin fibroblasts, with an IC50 of 100 nM. At 0.5 μM for 36 hours, it does not significantly inhibit the invasion of tachyzoites but causes severe morphological abnormalities. Ethalfluralin (1 μM; 0-24 h) eliminates the plaque-forming ability of tachyzoites within 8-12 hours without affecting the viability of extracellular tachyzoites treated for 12 hours. Its effects last up to 24 hours but do not inhibit nucleic acid synthesis in intracellular tachyzoites, although it can completely clear parasite activity. Ethalfluralin (1 μM; 20 h) blocks nuclear division in intranuclear spindle formation, retaining submembrane microtubules and causing expansion of the inner membrane compartment in T. gondii RH strain tachyzoites. Additionally, ethalfluralin (1 μM) inhibits calcium ionophore-induced release of tachyzoites from human fibroblasts, leading to reduced vacuolar space and enhanced parasite refractivity post-treatment.

Ethalfluralin (6-12 mg/L; water immersion; continuous daily exposure; 96 hours) exhibits dose-dependent developmental toxicity on zebrafish embryos, manifested as decreased survival rate, abnormal morphological development, increased apoptosis and ROS production, inhibited angiogenesis, and enhanced inflammatory response; its LC50 is 18.49 mg/L.