Sulfur-containing natural hinduchelins derivatives as potential antifungal agents against Rhizoctonia solani

Discovery of Novel Carboxamide Derivatives Containing Biphenyl Pharmacophore as Potential Fungicidal Agents Used for Resistance Management

Natural products are one of the main sources of drug and agrochemicals discovery. Biphenyls skeleton are ubiquitous structures in many classes of natural products, which indicate extensive biological activities. So, in order to investigate the potential applications for natural biphenyl derivatives, a series of novel carboxamide derivatives with diverse substituent patterns were designed and synthesized based on active pharmacophore from natural biphenyl lignans, and their in vitro antifungal activities against several typical plant pathogens belonging to oomycetes, ascomycete, deuteromycetes, and basidiomycetes were fully investigated. The highly potential compounds were further tested in vivo assay against Botrytis cinerea Pers. of cucumber to demonstrate a practical application for controlling common plant diseases, which indicated four compounds could effectively control the resistant strains of carbendazim, rutamycin, and pyrazolidide. The potential modes of action for compound B12 against B. cinerea were also explored using molecular docking, microscopic technology, and label-free quantitative proteomics analysis. The results show that compound B12 may be a potential novel fungicidal agent used for gray mold resistance control, which can influence the protein synthesis of B. cinerea. These findings can provide a certain theoretical basis for the development of novel biphenyl derivatives as potential green antifungal agents.

Discovery of a Novel Small-Molecule Inhibitor Disrupting TRBP-Dicer Interaction against Hepatocellular Carcinoma via the Modulation of microRNA Biogenesis

MicroRNAs (miRNAs) are key players in human hepatocellular carcinoma (HCC) tumorigenesis. Therefore, small molecules targeting components of miRNA biogenesis may provide new therapeutic means for HCC treatment. By a high-throughput screening and structural simplification, we identified a small molecule, CIB-3b, which suppresses the growth and metastasis of HCC in vitro and in vivo by modulating expression profiles of miRNAome and proteome in HCC cells. Mechanistically, CIB-3b physically binds to transactivation response (TAR) RNA-binding protein 2 (TRBP) and disrupts the TRBP-Dicer interaction, thereby altering the activity of Dicer and mature miRNA production. Structure-activity relationship study via the synthesis of 45 CIB-3b derivatives showed that some compounds exhibited a similar inhibitory effect on miRNA biogenesis to CIB-3b. These results support TRBP as a potential therapeutic target in HCC and warrant further development of CIB-3b along with its analogues as a novel therapeutic strategy for the treatment of HCC.

Synthesis, In Silico and In Vitro Evaluation of Antimicrobial and Toxicity Features of New 4-[(4-Chlorophenyl)sulfonyl]benzoic Acid Derivatives

The multi-step synthesis, physico-chemical characterization, and biological activity of novel valine-derived compounds, i.e., N-acyl-α-amino acids, 1,3-oxazol-5(4H)-ones, N-acyl-α-amino ketones, and 1,3-oxazoles derivatives, bearing a 4-[(4-chlorophenyl)sulfonyl]phenyl moiety are reported here. The structures of the newly synthesized compounds were confirmed by spectral (UV-Vis, FT-IR, MS, ¹H- and ¹³C-NMR) data and elemental analysis results, and their purity was determined by RP-HPLC. The new compounds were assessed for their antimicrobial activity and toxicity to aquatic crustacean Daphnia magna. Also, in silico studies regarding their potential mechanism of action and toxicity were performed. The antimicrobial evaluation revealed that the 2-{4-[(4-chlorophenyl)sulfonyl]benzamido}-3-methylbutanoic acid and the corresponding 1,3-oxazol-5(4H)-one exhibited antimicrobial activity against Gram-positive bacterial strains and the new 1,3-oxazole containing a phenyl group at 5-position against the C. albicans strain.

Synthesis and biological activities of novel trifluoromethylpyridine amide derivatives containing sulfur moieties

A series of trifluoromethylpyridine amide derivatives containing sulfur moieties (thioether, sulfone and sulfoxide) was designed and synthesized. Their antibacterial activities against Xanthomonas oryzae pv. oryzae (Xoo), Ralstonia solanacearum (R. solanacearum) and insecticidal activities against P. xylostella were evaluated. Notably, the half-maximal effective concentration (EC50) value of sulfone-containing compound F10 is 83 mg L-1 against Xoo, which is better than that of commercial thiodiazole copper (97 mg L-1) and bismerthiazol (112 mg L-1). Thioether-containing compounds E1, E3, E5, E6, E10, E11 and E13 showed much higher activities against R. solanacearum with the EC50 value from 40 to 78 mg L-1, which are much lower than that of thiodiazole copper (87 mg L-1) and bismerthiazol (124 mg L-1). Generally, most of the sulfone-containing compounds and sulfoxide-containing compounds showed higher activities against Xoo than that of the corresponding thioether-containing compound, but most of the thioether-containing compounds contributed higher antibacterial activities against R. solanacearum. Furthermore, title compounds E3, E11, E24 and G2 showed good insecticidal activities of 75%, 70%, 70% and 75%, respectively.

Secondary metabolites as plant defensive strategy: a large role for small molecules in the near root region

The roles of plant roots are not merely limited to the provision of mechanical support, nutrients and water, but also include more specific roles, such as the capacity to secrete diverse chemical substances. These metabolites are actively secreted in the near root and play specific and significant functions in plant defense and communication. In this review, we detail the various preventive roles of these powerful substances in the rhizosphere with a perspective as to how plants recruit microbes as a preventive measure against other pathogenic microbes, also, briefly about how the rhizosphere can repel insect pests, and how these chemical substances alter microbial dynamics and enhance symbiotic relationships. We also highlight the need for more research in this area to detail the mode of action and quantification of these compounds in the environment and their roles in some important biological processes in microorganisms and plants.