Discovery, Optimization, and Biological Evaluation of Novel Pyrazol-5-yl-phenoxybenzamide Derivatives as Potent Succinate Dehydrogenase Inhibitors.

The diphenyl ether molecular pharmacophore has played a significant role in the development of fungicidal compounds. In this study, a variety of pyrazol-5-yl-phenoxybenzamide derivatives were synthesized and evaluated for their potential to act as succinate dehydrogenase inhibitors (SDHIs). The bioassay results indicate certain compounds to display a remarkable and broad-spectrum in their antifungal activities. Notably, compound 12x exhibited significant in vitro activities against Valsa mali, Gaeumannomyces graminis, and Botrytis cinerea, with EC50 values of 0.52, 1.46, and 3.42 mg/L, respectively. These values were lower or comparable to those of Fluxapyroxad (EC50 = 12.5, 1.93, and 8.33 mg/L, respectively). Additionally, compound 12x showed promising antifungal activities against Sclerotinia sclerotiorum (EC50 = 0.82 mg/L) and Rhizoctonia solani (EC50 = 1.86 mg/L), albeit lower than Fluxapyroxad (EC50 = 0.23 and 0.62 mg/L). Further in vivo experiments demonstrated compound 12x to possess effective protective antifungal activities against V. mali and S. sclerotiorum at a concentration of 100 mg/L, with inhibition rates of 66.7 and 89.3%, respectively. In comparison, Fluxapyroxad showed inhibition rates of 29.2 and 96.4% against V. mali and S. sclerotiorum, respectively. Molecular docking analysis revealed that compound 12x interacts with SDH through hydrogen bonding, π-cation, and π-π interactions, providing insights into the probable mechanism of action. Furthermore, compound 12x exhibited greater binding energy and SDH enzyme inhibitory activity than Fluxapyroxad (ΔGcal = -46.8 kcal/mol, IC50 = 1.22 mg/L, compared to ΔGcal = -41.1 kcal/mol, IC50 = 8.32 mg/L). Collectively, our results suggest that compound 12x could serve as a promising fungicidal lead compound for the development of more potent SDHIs for crop protection.

Design, Synthesis, and Fungicidal Activities of Novel N-(Pyrazol-5-yl)benzamide Derivatives Containing a Diphenylamine Moiety.

To accelerate the development of novel fungicides, a variety of N-(pyrazol-5-yl)benzamide derivatives with a diphenylamine moiety were designed and synthesized using a pharmacophore recombination strategy based on the structure of pyrazol-5-yl-aminophenyl-benzamides. The bioassay results demonstrated that most of the target compounds had excellent in vitro antifungal activities against Sclerotinia sclerotiorum, Valsa mali, and Botrytis cinerea. In particular, compound 5IIIh exhibited remarkable activity against S. sclerotiorum (EC50 = 0.37 mg/L), which was similar to that of fluxapyroxad (EC50 = 0.27 mg/L). In addition, compound 5IIIc (EC50 = 1.32 mg/L) was observed to be more effective against V. mali than fluxapyroxad (EC50 = 12.8 mg/L) and comparable to trifloxystrobin (EC50 = 1.62 mg/L). Furthermore, compound 5IIIh demonstrated remarkable in vivo protective antifungal properties against S. sclerotiorum, with an inhibition rate of 96.8% at 100 mg/L, which was close to that of fluxapyroxad (99.6%). Compounds 5IIIc (66.7%) and 5IIIh (62.9%) exhibited good in vivo antifungal effects against V. mali at 100 mg/L, which were superior to that of fluxapyroxad (11.1%) but lower than that of trifloxystrobin (88.9%). The succinate dehydrogenase (SDH) enzymatic inhibition assay was conducted to confirm the mechanism of action. Molecular docking analysis further revealed that compound 5IIIh has significant hydrogen-bonding, π-π, and p-π conjugation interactions with ARG 43, SER 39, TRP 173, and TYR 58 in the binding site of SDH, and the binding mode was similar to that of the commercial fungicide fluxapyroxad. All of the results suggest that compound 5IIIh could be a potential SDH inhibitor, offering a valuable reference for future studies.

Novel N-(1H-Pyrazol-5-yl)nicotinamide Derivatives: Design, Synthesis and Antifungal Activity.

To discover more effective antifungal agents, twenty N-(1H-pyrazol-5-yl)nicotinamide derivatives were designed, synthesized, and structurally confirmed by 1 H-NMR, 13 C-NMR, and ESI-MS. All target compounds were evaluated for their antifungal activities by mycelia growth inhibition. Preliminary screening results displayed that many of these compounds had good fungicidal activity to S. sclerotiorum and V. mali. Compound B4 exhibited antifungal activity against S. sclerotiorum and V. mali with EC50 values of 10.35 and 17.01 mg/L, respectively. The experiment in vivo identified that compound B4 was effective for suppressing rape sclerotinia rot caused by S. sclerotiorum at 50 mg/L. The molecular docking study and scanning electron microscopy preliminary clarified the possible antifungal mechanism of compound B4.

CDKN3 expression predicates poor prognosis and regulates adriamycin sensitivity in hepatocellular carcinoma in vitro.

OBJECTIVE: Hepatocellular carcinoma (HCC) is one of the most common causes of cancer-related deaths worldwide. This study investigated the relationship between cyclin-dependent kinase inhibitor (CDKN)3 and prognosis and pathological characteristics in HCC patients to determine whether it could be used as a prognostic factor and/or therapeutic target for HCC drug development. METHODS: We previously showed that CDKN3 is deregulated in HCC tumor samples. Here, bioinformatics analysis was used to assess the relationship between CDKN3 gene expression and the characteristics of HCC patients from Gene Expression Omnibus and The Cancer Genome Atlas databases. Additionally, CDKN3 expression was silenced by small interfering RNA to determine its effect on HCC cell proliferation and on HCC cell sensitivity to adriamycin chemotherapy. RESULTS: Bioinformatics analysis showed a negative correlation between CDKN3 expression and both disease-free survival and overall survival. CDKN3 silencing did not significantly suppress the proliferation of HCC cells, but did decrease their sensitivity to adriamycin. CONCLUSIONS: CDKN3 may have a dual role during the development of HCC, and could be used as an independent prognostic factor and therapeutic target for HCC treatment.

Histamine-related hygienic qualities and bacteria found in popular commercial scombroid fish fillets in Taiwan.

To determine the histamine-related hygienic qualities and bacteria of scombroid fish fillets sold in traditional retail markets, 61 samples were collected from northern and southern Taiwan. It was found that the content of volatile base nitrogen in most samples was below 25 mg/100 g, which is the regulatory level in Taiwan. The ratio of unacceptable samples/total samples for aerobic plate count and Escherichia coli was 100% and 15% in northern samples and 100% and 20% in southern samples, respectively, compared with the requirements of hygienic standards. The average content of various biogenic amines in all samples were lower than 3 mg/100 g, except for histamine average content (4.6 mg/100 g) in southern samples. Among southern samples, four samples contained 12.8 to 28.8 mg/100 g histamine, which is more than 5 mg/100 g that is the allowable limit suggested by the U.S. Food and Drug Administration. Furthermore, 14 bacterial strains were isolated from sailfish fillets on a selective medium for histamine-forming bacteria. These presumptive histamine-forming strains, such as Proteus, Enterobacter, Klebsiella, Rahnella, and Acinetobacter, have been identified and found to produce 20 to 2,000 ppm histamine after incubating at 37 degrees C for 24 h.