Design, Synthesis, and Bioactivity of Novel Quinazolinone Scaffolds Containing Pyrazole Carbamide Derivatives as Antifungal Agents.

In this study, 32 novel quinazolinone-scaffold-containing pyrazole carbamide derivatives were designed and synthesized in a search for a novel fungicide against Rhizoctonia solani. Single-crystal X-ray diffraction of 3-(difluoromethyl)-N-(2-((6,7-difluoro-4-oxoquinazolin-3(4H)-yl)methyl)phenyl)-1-methyl-1H-pyrazole-4-carboxamide (6a11) confirmed the structure of the target compounds. The in vitro antifungal activity of the target compounds against R. solani was evaluated at 100 µg/mL. The structure-activity relationship analysis results revealed that antifungal activity was highest when the substitution activity was at position 6. Moreover, the position and number of chlorine atoms directly affected the antifungal activity. Further in vitro bioassays revealed that 6a16 (EC50 = 9.06 mg/L) had excellent antifungal activity against R. solani that was higher than that of the commercial fungicide fluconazole (EC50 = 12.29 mg/L) but lower than that of bixafen (EC50 = 0.34 mg/L). Scanning electron microscopy), 7.33 (SEM) revealed that N-(2-((6,8-dichloro-4-oxoquinazolin-3(4H)-yl)methyl)phenyl)-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxamide (6a16) also affected the mycelial morphology. The findings revealed that molecular hybridization was an effective tool for designing antifungal candidates. Meanwhile, pyrazolecarbamide derivatives bearing a quinazolinone fragment exhibited potential antifungal activity against R. solani.

Synthesis and Bioactivity of Novel Sulfonate Scaffold-Containing Pyrazolecarbamide Derivatives as Antifungal and Antiviral Agents.

Novel pyrazolecarbamide derivatives bearing a sulfonate fragment were synthesized to identify potential antifungal and antiviral agents. All the structures of the key intermediates and target compounds were confirmed by nuclear magnetic resonance (NMR) and high-resolution mass spectrometry (HRMS). The single-crystal X-ray diffraction of the compound T22 showed that pyrazole carbamide is a sulfonate. The in vitro antifungal activities of the target compounds against Colletotrichum camelliae, Pestalotiopsis theae, Gibberella zeae, and Rhizoctonia solani were evaluated at 50 µg/ml. Among the four pathogens, the target compounds exhibited the highest antifungal activity against Rhizoctonia solani. The compound T24 (EC50 = 0.45 mg/L) had higher antifungal activity than the commercial fungicide hymexazol (EC50 = 10.49 mg/L) against R. solani, almost similar to bixafen (EC50 = 0.25 mg/L). Additionally, the target compounds exhibited protective effects in vivo against TMV. Thus, this study reveals that pyrazolecarbamide derivatives bearing a sulfonate fragment exhibit potential antifungal and antiviral activities.

A Review on the Extraction, Bioactivity, and Application of Tea Polysaccharides.

Tea is a non-alcoholic drink containing various active ingredients, including tea polysaccharides (TPSs). TPSs have various biological activities, such as antioxidant, anti-tumor, hypoglycemic, and anti-cancer activities. However, TPSs have a complex composition, which significantly limits the extraction and isolation methods, thus limiting their application. This paper provides insight into the composition, methodological techniques for isolation and extraction of the components, biological activities, and functions of TPSs, as well as their application prospects.

Cucurbit[7]uril as a matrix solid-phase dispersion for the extraction of quaternary ammonium pesticides from vegetables and their determination using HPLC-UV.

Cucurbit[7]uril (Q[7]) was first used as a dispersant sorbent material in a matrix solid-phase dispersion for the simultaneous extraction of four quaternary ammonium pesticides from vegetables before analysis using high-performance liquid chromatography with UV detection. Q[7] exhibited a better selectivity and adsorption capability for these compounds, which is due to its ability to bind selectively organic molecules into its hydrophobic cavity and to form stable host-guest inclusion complexes. Various parameters affecting the extraction were investigated and optimized, such as sorbent/sample mass ratio, grinding time, rinsing and eluting conditions. Under optimized conditions, the proposed method exhibited a linear response in the concentration range of 1-100 µg·kg-1, satisfactory recoveries for eight types of vegetable samples (>70%), and high repeatability (RSD < 9.0%). The limits of quantification were between 0.43 µg·kg-1 and 0.99 µg·kg-1, which is nearly 50 times lower than the maximum residue limits established by the European Council.

Specific recognition of cationic paraquat in environmental water and vegetable samples by molecularly imprinted stir-bar sorptive extraction based on monohydroxylcucurbit[7]uril-paraquat inclusion complex.

Molecularly imprinted stir-bar coatings were created based on a hydroxylcucurbit[7]uril-paraquat inclusion complex. The inclusion complex that contained paraquat (PQ) as a template and monohydroxylcucurbit[7]uril ((OH)Q[7]) as a monomer was preassembled mainly through cavity inclusion interaction of (OH)Q[7] to form a one-dimensional self-assembly structure. The inclusion complex was anchored chemically on the surface of a glass stir bar with hydroxy-terminated poly(dimethylsiloxane) by the sol-gel technique to obtain a molecularly imprinted polymer-coated stir bar (MIP-SB). The molecularly imprinted coating showed specific adsorption for cationic PQ in aqueous media. Other quaternary amine compounds with a similar structure that coexisted in the solution, such as ethyl-viologen, diquat, and difenzoquat, were almost not extracted by the prepared MIP-SB. The sorptive capacity of the MIP-SB for PQ was nearly four times that of the non-imprinted stir bar (NIP-SB). The recognition mechanism indicated that the selectivity and extraction capacity resulted mainly from the imprinted cavity in the polymer that was formed by a one-dimensional assembly structure consisting of the (OH)Q[7]-PQ inclusion complex. The imprinted cavity was complementary to the PQ in shape, size, and functionality. A method to determine PQ in environmental water and vegetable samples was developed by combining MIP-SB sorptive extraction with HPLC-UV. The linear range was from 100 to 10,000 ng L-1 with a 8.2 ng L-1 detection limit for water samples and 0.02-0.85 mg kg-1 with a 0.005 mg kg-1 detection limit for vegetable samples. The limit of detection for both samples was lower than the EU-established maximum residual levels and that of other previously reported methods. The average recoveries were 70.0-96.1% with a relative standard deviation ≤ 7.6%, which showed the successful application in real sample analysis. Molecularly imprinted stir-bar coatings were created based on a hydroxylcucurbit[7]uril-paraquat (PQ) inclusion complex, which showed a specific recognition toward cationic PQ. A method to determine PQ in environmental water and vegetable samples was established by combining MIP-SB sorptive extraction with HPLC-UV.

Separation Performance of Capillary Gas Chromatography Based on Monohydroxycucurbit[7]Uril Incorporated Into Sol-Gels as the Stationary Phase.

A novel monohydroxycucurbit[7]uril-based stationary phase for capillary gas chromatography (GC) has been produced. For this, a capillary column coating was made using a sol-gel technique, incorporating synthesized monohydroxycucurbit[7]uril [(OH)Q[7]] and hydroxy-terminated poly(dimethylsiloxane) (OH-PDMS) into the sol-gel network through hydrolysis and polycondensation and chemical sol-gel grafting to the inner wall of a fused-silica tube. The preparation method may produce a coating with greater integrity, which gives the prepared column a higher separation efficiency and better selectivity toward analytes than a reported stationary phase based on neat cucurbit[n]urils (Q[n]s). The prepared (OH)Q[7]/PDMS column had 3,225 theoretical plates per meter determined using naphthalene at 120°C and exhibited a weakly polar nature. The (OH)Q[7]/PDMS column has high resolution over a broad spectrum of analytes with symmetrical peak shapes and exhibited better separation performance than commercial capillary columns and reported columns based on neat Q[n]s that failed to resolve some critical analytes. Moreover, the column also showed good thermal stability up to 300°C and separation repeatability with relative standard deviation values in the range of 0.01-0.11% for intraday, 0.11-0.32% for interday and 0.29-0.58% for column-to-column. In addition, the energy effect on the retention of analytes on the (OH)Q[7]/PDMS stationary phase was investigated. The results indicated that retention on the column was determined mainly by the enthalpy change. As demonstrated, the proposed coating method can address some disadvantages that exist with the reported Q[n]s columns and combine the full advantages of (OH)Q[7] with the sol-gel coating method while achieving outstanding GC separation performance.

Monohydroxycucurbit[7]uril-coated stir-bar sorptive extraction coupled with high-performance liquid chromatography for the determination of apolar and polar organic compounds.

A detailed study has been carried out on monohydroxycucurbit[7]uril-based stir-bar sorptive extraction (SBSE). A polydimethylsiloxane coating was produced by a sol-gel technique and doped with monohydroxycucurbit[7]uril ((HO)1Q [7]) as a selective sorbent phase. (HO)1Q [7] was chemically bound to the sol-gel silica substrate through hydrolysis and polycondensation. The coating possesses a porous surface, shows strong solvent resistance and good thermal stability, and has a long lifespan. Four groups of compounds, with polarities ranging from apolar polycyclic aromatic hydrocarbons to polar ketones, aromatic amines and phenols, were selected as test analytes. They were extracted with the coated stir bar, then desorbed with methanol and quantified by high-performance liquid chromatography with ultraviolet detection. The limits of detection range between 1.3 and 15 µg L-1, the linear ranges extend from 5 to 10,000 µg L-1, and the relative recoveries from spiked samples range between 76.4 and 97.9%. The intraday relative standard deviations range from 2.3 to 8.6% (for n = 3, at 500 µg L-1). Compared with a commercial PDMS-coated stir bar and a polyether sulfone-coated stir bar, the new stir bar shows wider applicability and better extraction efficiency for each group of compounds. In addition, the stir bar can simultaneously extract mixtures of chemicals of different polarities. This endows it with the potential for recovering a broad group of polar organic compounds. Graphical abstractA stir bar for sorptive extraction based on monohydroxycucurbit[7]uril has been prepared by a sol-gel technique. The stir bar coupled with HPLC with UV detection allows for the determination of a variety of polar compounds and multicomponent mixtures, respectively.