Chemical profiling by LC–MS/MS and HPLC fingerprint combined with chemometrics and simultaneous determination of 16 characteristic ingredients for the quality consistency evaluation of Shaoyao‐Gancao Decoction

In this paper, to evaluate the effect of the region of origin on the quality consistency of Shaoyao‐Gancao Decoction (SGD), the SGD fingerprint was developed for the first time. Chemometric methods including similarity analysis, hierarchical clustering analysis and principal component analysis were employed to study the quality consistency of SGD. Meanwhile, high‐performance liquid chromatography coupled with electrospray ionization quadrupole time‐of‐flight mass spectrometry was applied for comprehensive analysis of SGD and 93 compounds were tentatively characterized. Furthermore, a high‐performance liquid chromatography method with multi‐wavelength switching for simultaneous determination of 16 characteristic ingredients comprising gallic acid, oxypaeniflorin, albiflorin, paeoniflorin, liquiritin apioside, liquiritin, isoliquiritin apioside, galloylpaeoniflorin, 1,2,3,4,6‐penta‐O‐galloyl‐d ‐galactopyranose (PGG), ononin, isoliquiritin, liquiritigenin, benzoylpaeoniflorin, glycyrrhizic acid, isoliquiritigenin and formononetin, was established. All 16 analytes show excellent linearity (R² ≥ 0.9990) with recoveries ranging from 96.58 to 104.61% and limits of detection and quantification of 0.022–0.291 and 0.037–0.635 μg/mL, respectively. Finally, it was successfully applied to determine 15 batches of SGD. The results of our research indicate that different regions of origin have a significant effect on the quality consistency of SGD, and its fingerprint combined with chemometrics and multi‐ingredient determination comprise an efficient and reliable approach for quality consistency evaluation.     

Facile Heterocyclic Synthesis and Antibacterial Activity of Substituted Isoxazol‐5(4H)‐ones

An efficient, simple, and green procedure for the synthesis of isoxazol‐5(4H)‐one derivatives are described here through a convenient one‐pot, three‐component reaction at room temperature. The title compounds are isolated in high to excellent yields and after short reaction times, and are characterized by various spectroscopic methods such as IR, ¹H NMR, and ¹³C NMR. The synthesized compounds 4a–c and 4e–i were tested for their in vitro activity against a panel of Gram‐positive and Gram‐negative bacteria, demonstrating their ability to inhibit microorganisms with a zone of inhibition ranging from 15 to 30 mm, minimum inhibitory concentration between 250 and 900 μg/mL, and minimum bacterial concentration between 700 and 1000 μg/mL.     

Optimization of extraction for Anemarrhena asphodeloides Bge. using silica gel‐based vortex‐homogenized matrix solid‐phase dispersion and rapid identification of antioxidant substances

A novel and simple method was established for the extraction and determination of seven compounds in Anemarrhena asphodeloides Bge. using silica gel‐based vortex‐homogenized matrix solid‐phase dispersion and ultra‐high performance liquid chromatography quadrupole‐time of‐flight mass spectrometer. The conditions for the extraction were optimized. Silica gel was used as the dispersant, 50% methanol–water was selected as an elution solvent and the grinding time was 3 min. Compared with the traditional ultrasonic‐assisted extraction, the developed method was rapid and efficient. In order to screen potential antioxidants, extract dealing with the optimized method was applied to a polyamide chromatography column and a D‐101 macroporous resin column. Fr.2.2 showed the highest antioxidant activities with the most content of flavonoid. A total of 25 peaks were identified from the active fraction. A 2,2′‐diphenyl‐1‐picrylhydrazyl ultra‐high performance liquid chromatography coupled with mass spectrometry approach was adopted for the rapid and exact screening and identification of antioxidant compounds. It indicated that flavonoids exhibited potential antioxidant activities. The antioxidant activities of nine monomeric compounds in vivo were tested. Structure–activity relationships were discussed. Five flavonoids with the concentration of 500 µg/mL would reduce the oxidative stress of PC12 cells that were induced with 2,2′‐azobis[2‐methylpropionamidine] dihydrochloride.     

Design,synthesis, and biological activity of novel 2‐(pyridin‐3‐yl)ethan‐1‐one oxime ethers bearing adamantane moiety

With the aim of discovering a lead compound for pyridine‐based fungicide bearing adamantane moiety, a series of novel O‐alkyl/benzyl‐1‐(adamantan‐1‐yl)‐2‐(pyridin‐3‐yl)ethan‐1‐one oximes were synthesized from 3‐methylpyridine, ethyl (adamantan‐1‐yl)carboxylate, and alkoxyamine or benzoxyamine hydrochloride. The in vitro antifungal activity against four pathogenic fungi was evaluated, and some compounds exhibited good antifungal activity. Compounds 3d and 3f demonstrated strong activity against Sclerotinia sclerotiorum, with EC₅₀ values of 11.25 and 12.87 μg/mL, respectively; 3b , 3c, and 3k had notable activity against Botrytis cinerea, with EC₅₀ values of 12.78, 12.57, and 11.97 μg/mL, respectively. For Rhizoctonia Solani, 3d and 3g showed sufficient activity with EC₅₀ values of 9.66 and 8.90 μg/mL, respectively. In addition, 3d and 3g demonstrated moderate activity against Colletotrichum orbiculare, with EC₅₀ values of 14.32 and 15.83 μg/mL, respectively.     

Synthesis and antioxidant activities of novel N‐aryl (and N‐alkyl) γ‐ and δ‐imino esters and ketimines

Novel N‐aryl (and N‐alkyl) γ‐ and δ‐imino esters 2a–g ( 3a–g ) and N‐aryl (and N‐alkyl) ketimines 2h–j ( 3h–j ) were synthesized in high yields (80–99%) from their corresponding γ‐ and δ‐keto esters and ketones in this study. The structures of the synthesized compounds were clarified by Fourier transform infrared (FT‐IR), NMR (¹H and ¹³C), mass spectrometry, and elemental analyses. Isomerizations [E/Z] were also determined by their ¹H NMR spectra. The free‐radical scavenging activity of imines was evaluated using the 1,1‐diphenyl‐2‐picryl‐hydrazyl (DPPH) method. The relationships between the structure and antioxidant activity of these compounds are discussed. Among these compounds, 2a–c (at the concentration 1000 μg/mL) exhibit high antioxidant activity similar to those of the standards (butylated hydroxyanisole [ BHA], butylated hydroxytoluene [ BHT], and ascorbic acid).     

Novel affinity purification of monomeric sarcosine oxidase expressed in Escherichia coli

An efficient affinity‐purification protocol for Bacillus monomeric sarcosine oxidase (SOX) expressed in Escherichia coli BL21 (DE3) was developed. 4‐Aminopyrrole‐2‐carboxylic acid was chosen as the affinity ligand, which was coupled with Sepharose CL 4B via spacers composed of epichlorohydrin and ethylenediamine. With the affinity medium, the purification process consisted of only one affinity chromatography step to capture monomeric SOX. The purified SOX was 94 and 96% pure when analyzed on an HPLC Vydac C₈ column and reducing SDS‐PAGE. Meanwhile, the recoveries of typical SOX activity and protein were 90.8 and 37.5%, respectively, which were higher than other reported traditional protocols. Reducing SDS‐PAGE analysis revealed that the enzyme was a single polypeptide with the mass of ～46 kDa. The desorption constant K_d and theoretical maximum absorption Q_max were 35 μg/mL and 52.7 mg/g, respectively, in absorption analysis. All results indicated that the method would be of great potential for purifying monomeric SOX on an industrial scale.     

Synthesis and Antitubercular Evaluation of N‐Arylpyrazine and N,N′‐Alkyl‐diylpyrazine‐2‐carboxamide Derivatives

Two series of pyrazinamide (PZA) derivatives have been synthesized and evaluated for their in vitro antibacterial activity against Mycobacterium tuberculosis H37Rv. Some compounds exhibited minimum inhibitory concentration activity of 50–100 μg/mL, greater than the first line antituberculosis drug PZA in Alamar Blue assay (>100 μg/mL). The obtained activities can be considered promising results, which characterizes these compounds as good start points to development of new antitubercular agents.     

Comparison of microwave‐assisted and heat reflux extraction techniques for the extraction of ten major compounds from Zibu Piyin Recipe using ultra high performance liquid chromatography with tandem mass spectrometry

Microwave‐assisted extraction and efficient ultra‐high performance liquid chromatography with triple quadrupole mass spectrometry were previously used to quickly extract and simultaneously quantify ginsenoside Rf, Ro, and Rd, 20(S)‐ginsenoside‐Rg₂, 20(R)‐ginsenoside‐Rg₂, tanshinone IIA, cryptotanshinone, dihydrotanshinone I, lithospermic acid, and osthole from Zibu Piyin Recipe. We here showed that heat reflux extraction provides higher extraction efficiency of these target compounds but is more time consuming. Chromatographic separation was achieved on an Agilent ZORBAX RRHD Eclipse Plus C₁₈ column with a gradient mobile phase consisting of water/0.5% formic acid and acetonitrile at a flow rate of 0.2 mL/min, and detection was performed by positive and negative ion multiple‐reaction monitoring mode. All analytes showed good linearity (r, 0.9989–0.9999) within the test range, with a limit of detection of 0.002–0.180 μg/mL. The overall intra‐ and interday variations of the ten compounds were ≤2.9%, and the accuracy was evaluated using a recovery test at three concentrations and was in the range 97.61–103.18% (RSD ≤ 4.25%). The analytical results showed remarkable differences in the concentrations of the ten compounds extracted from Zibu Piyin Recipe by microwave‐assisted extraction and heat reflux extraction. These findings provide important information for determining the quality of Zibu Piyin Recipe.     

Simultaneous extraction and determination of various pesticides in environmental waters

A simple and rapid method was developed for the simultaneous analysis of nine different pesticides in water samples by gas chromatography with mass spectrometry. A number of parameters that may affect the recovery of pesticides, such as the type of solid‐phase extraction cartridge, eluting solvent in single or combination and their volumes, and water pH value were investigated. It showed that three solid‐phase extraction cartridges (Strata‐X, Oasis HLB, and ENVI‐18) produced the greatest recovery while ethyl acetate/dichloromethane/acetone (45:10:45, 12 mL) followed by dichloromethane (6 mL) was efficient in eluting target pesticides from solid‐phase extraction cartridges. Different water pH values (4–9) did not show a significant effect on the pesticides recovery. The optimized method was verified by performing spiking experiments with a series of concentrations (0.002–10 μg/L) in waters, with good linearity, recovery, and reproducibility for most compounds. The limit of detection and limit of quantification of this optimized method were 0.01–2.01 and 0.02–6.71 ng/L, respectively, much lower than the European Union environmental quality standard for the pesticides (0.1 μg/L) in waters. The proposed method was further validated by participation in an interlaboratory trial. It was then subsequently applied to river waters from north‐east Scotland, UK, for the determination of the target pesticides.     

Potential of Flame Ionization Detection Coupled On‐Line with Microcolumn Liquid Chromatography Using Aqueous Eluents and an Eluent‐Jet Interface

The potential of the on‐line coupling of microcolumn liquid chromatography (μLC) using aqueous eluents with a flame ionization detector (FID) was evaluated. An eluent‐jet interface was modified to allow the efficient introduction of the eluent into the FID. The potential of the method is demonstrated by the μLC–FID determination of lower alcohols and bis(2‐hydroxyethylthio)alkanes on porous and non‐porous stationary phases, respectively. Flow injection analysis (FIA)–FID experiments with highly polar, thermolabile, semi‐volatile and non‐volatile compounds like amino acids, organic acids, alkylphosphonic acids, and carbohydrates showed the developed configuration to be a promising approach for the detection of a wide range of analytes. Compared with a nebulization interface, the eluent‐jet interface showed 4–10 times higher peaks for citric acid. Detection limits by FIA for all compounds were in the range of 0.2–5 ng injected. With ribose as test compound, plots of peak height vs. amount injected showed good linearity (r² > 0.999) in the range of 75–12,000 μg/mL. The repeatability showed relative standard deviations of less than 5%.     

Design,Synthesis, and in vitro Antimicrobial Activity of New Furan/Thiophene‐1,3‐Benzothiazin‐4‐one Hybrids

This study presents the design, synthesis, spectral analysis, and in vitro antimicrobial evaluation of a new series of furan/thiophene‐1,3‐benzothiazin‐4‐one hybrids ( 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 ). New compounds were obtained by cyclization reaction of N‐substituted furan/thiophene‐2‐carboxamide derivatives ( 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 ) with thiosalicylic acid. All synthesized compounds were screened for their in vitro antimicrobial activities using the broth microdilution method. Nine of the synthesized compounds showed good activity against Gram‐positive, Gram‐negative bacteria, and yeasts belonging to Candida spp. (MIC = 7.81–500 μg/mL), especially against Staphylococcus spp. (MIC = 15.62–62.5 μg/ml), Bacillus spp. (MIC = 7.81–62.5 μg/mL), Bordetella bronchiseptica ATCC 4617 (MIC = 62.5–125 μg/mL), and fungistatic activity against Candida spp. (MIC = 62.5–125 μg/mL).     

Novel Symmetrical trans‐Bis‐Schiff Bases of N‐Substituted‐4‐ piperidones: Synthesis,Characterization, and Preliminary Antileukemia Activity Mensurations

A series of novel symmetrical trans‐bis‐Schiff bases ( 11a , 11b , 11c , 11d , 11e , 11f , 11g , 11h , 11i , 11j , 11k , 11l , 11m ) were designed and prepared as novel anticancer analogues, with the trans‐configuration confirmed by X‐ray diffraction. Preliminary inhibitory effects of these compounds on CML K562 cell growth were investigated, and the potential analogue 11e showed an excellent anti‐leukemia activity (IC₅₀=6.35 μg/mL), which is higher than that of the clinical drug 5‐fluorouracil (IC₅₀=8.48 μg/mL). Complete assignments had been achieved for the title compounds by spectroscopic techniques, and their structure–activity relationships have been studied.     

Synthesis and Antifungal Activity Evaluation of Novel Substituted Pyrimidine‐5‐Carboxamides Bearing the Pyridine Moiety

A series of novel N‐(substituted phenyl/benzyl)‐2‐methylthio‐4‐((pyridin‐3‐ylmethyl)amino)pyrimidine‐5‐carboxamides were synthesized by multistep reactions. The structures of the target compounds were characterized by IR, ¹H NMR, ¹³C NMR, and elemental analysis. Their in vitro antifungal activities against two kinds of plant pathogenic fungi were evaluated by the mycelial growth rate method. The result showed that at the dosage of 100 μg/mL, several of these compounds exhibited moderate activity against Botrytis cinerea with inhibition rates of ~70%, and most compounds (e.g., 5a , 5c , 5e , 5f, and 5h ) possessed excellent activity against Sclerotinia Sclerotiorum with more than 90% inhibition rate.     

Covalent bonding of homochiral metal‐organic framework in capillaries for stereoisomer separation by capillary electrochromatography

In this work, a [Cu(mal)(bpy)]?H₂O (mal, l ‐(?)‐malic acid; bpy, 4,4′‐bipyridyl) homochiral metal‐organic frameworks (MOFs) was synthesized and used for modifying the inner walls of capillary columns by utilizing amido bonds to form covalent links between the MOFs particles and capillary inner wall. The synthesized [Cu(mal)(bpy)]?H₂O and MOFs‐modified capillary column were characterized by X‐ray diffraction, thermogravimetric analysis, particle size distribution analysis, nitrogen absorption characterization, FTIR spectroscopy, SEM, and energy‐dispersive X‐ray spectroscopy (EDX). The MOFs‐modified capillary column was used for the stereoisomer separation of some drugs. The LODs and LOQs of six analytes were 0.1 and 0.25 μg/mL, respectively. The linear range was 0.25–250 μg/mL for ephedrine, 0.25–250 μg/mL for pseudoephedrine, 0.25–180 μg/mL for d ‐penicillamine, 0.25–120 μg/mL for l ‐penicillamine, 0.25–180 μg/mL for d ‐phenylalanine, and 0.25–160 μg/mL for l ‐phenylalanine, all with R² > 0.999. Finally, the MOFs‐modified capillary column was applied for the analysis of active ingredients in a real sample of the traditional Chinese medicine ephedra.     

Microwave‐assisted synthesis of 1,3′‐diaza‐flavanone/flavone and their alkyl derivatives with antimicrobial activity

A simple environmentally friendly solid‐phase microwave‐assisted method was used to synthesis of the 1,3′‐diazaflavanone ( 2 ) and 1,3′‐diazaflavone ( 3 ) from the cyclization of 2′‐amino (E)‐3″‐azachalcone ( 1 ). Ten new N‐alkyl (C_5–12,14,15)‐substituted 1,3′‐diazaflavanonium bromides ( 2a–j ) were prepared from compound 2 with corresponding alkyl halides in acetonitrile under reflux. In addition, nine new N,N′‐dialkyl (C_5–12,14)‐substituted 1,3′‐diazaflavonium bromides ( 3a–i ) were also synthesized from compound 3 with corresponding alkyl halides using basic silica in acetonitrile. The antimicrobial activities of compounds 1–3 , 2a–j , and 3a–i were tested against Gram‐positive (G+) (Bacillus subtilis, Staphylococcus epidermidis, Staphylococcus aureus, and Enterococcus faecalis) and Gram‐negative (G?) (Escherichia coli, Klebsiella pneumonia, Pseudomonas aeruginosa, Proteus vulgaris, Salmonella typhimirium, Yersinia pseudotuberculosis, and Enterobacter cloaceae) microorganisms. They showed good antimicrobial activity against the Gram‐positive bacteria tested with the minimal inhibitory concentration values less than 7.8 μg/mL in most cases. The optimum length of the alkyl chain for better and broader activity is situated in the range of 9–12 carbon atoms in the series of compounds 2a–j and five to six carbon atoms in the series of compounds 3a–i . The nonalkylated compounds 1–3 were not effective, as were the ones alkylated with five or six C alkyl groups ( 2a and 2b ) and 8–13 C alkyl groups for N,N′‐dialkyl compounds ( 3c–3i ). The antimicrobial activity increased as the length of the alkyl substitution increased from 8 to 12 carbons in compounds 2a–j . However, antimicrobial activity decreased as the length of the alkyl substitution increased from 7 to 13 carbons in compounds 3c–i . J. Heterocyclic Chem., (2012)     

Synthesis and Antimicrobial Evaluation of 1,4-Naphthoquinone Derivatives as Potential Antibacterial Agents

1,4-Naphthoquinones are an important class of compounds present in a number of natural products. In this study, a new series of 1,4-naphthoquinone derivatives were synthesized. All the synthesized compounds were tested for in vitro antimicrobial activity. In this present investigation, two Gram-positive and five Gram-negative bacterial strains and one pathogenic yeast strain were used to determine the antibacterial activity. Naphthoquinones tested for its antibacterial potencies, among seven of them displayed better antimicrobial activity against Staphylococcus aureus (S. aureus; 30–70 μg/mL). Some of the tested compounds showed moderate to low antimicrobial activity against Pseudomonas aeruginosa (P. aeruginosa) and Salmonella bongori (S. bongori; 70–150 μg/mL). In addition, most active compounds against S. aureus were evaluated for toxicity to human blood cells using a hemolysis assay. For better understanding, reactive oxygen species (ROS) generation, time-kill kinetic study, and apoptosis, necrosis responses were investigated for three representative compounds.     

An expedient reverse‐phase high‐performance chromatography (RP‐HPLC) based method for high‐throughput analysis of deferoxamine and ferrioxamine in urine

The present study was planned to optimize and validate an expedient reverse‐phase high chromatography (RP‐HPLC) based protocol for the analysis of deferoxamine (DFO) and ferrioxamine (FO) in urinary execration of patients suffering β ‐thalassemia major. The optimized RP‐HPLC method was found to be linear over the wide range of DFO and FO concentration (1–90 μg/mL) with appreciable recovery rates (79.64–97.30%) of quality controls at improved detection and quantitation limits and acceptable inter and intraday variability. Real‐time analysis of DFO and FO in the urine of thalassemic patients (male and female) at different intervals of Desferal®(Novartis Pharmaceuticals Corporation) injection revealed DFO and FO excretion at significantly (p < 0) different rates. The maximum concentrations of DFO (76.7 ± 3.06 μg/mL) and FO (74.2 ± 3.25 μg/mL) were found in urine samples, collected after 6 h of drug infusion while the minimum levels of DFO (1.10 ± 0.12 μg/mL) and FO (2.97 ± 0.13 μg/mL) were excreted by patients after 24 h. The present paper offers balanced conditions for an expedient, reliable and quick determination of DFO and FO in urine samples.     

Design,Synthesis and Biological Evaluation of Isothiazole Based 1,2,4‐Trizaole Derivatives

A series of novel 3,4‐dichloroisothiazole based 1,2,4‐triazole derivatives were rationally designed and synthesized. Their structures were confirmed by ¹H NMR, ¹³C NMR, HRMS or elemental analysis; the typical crystal structure was determined by X‐ray diffraction for validation. All target compounds were evaluated for their in vitro fungicidal and in vivo anti‐TMV activities. The bioassay results indicated that compound 6b , namely 1‐(3,4‐dichloroisothiazol‐5‐yl)‐1‐(4‐fluorophenyl)‐2‐(1H‐1,2,4‐triazol‐1‐yl)ethanol, exhibited excellent growth inhibition against B. cinerea, C. arachidicola and P. piricola with median effective concentrations (EC₅₀) of 6.98, 2.73 and 3.07 μg/mL, respectively, and good in vivo anti‐TMV activity of over 60% of inactivation and induction activity at 100 μg/mL. These data demonstrate that compound 6b is both a fungicide and an anti‐TMV lead, deserving further studies.     

Design,Synthesis and Antifungal Activity of Benzofuran and Its Analogues

Benzofuran has antifungal activity as the inhibitor of N‐myristoyltransferase. Twenty‐nine novel benzofuran‐semicarbazide hybrids were designed and synthesized by principle of drug combinationatory. On this basis, the benzofuran ring was simplified to a resorcinol structure, and sixteen novel 1,3‐dialkoxybenzene‐semicarbazide hybrids were designed and synthesized. All structures of the target compounds were characterized by HRMS and NMR. The in vitro antifungal activity of target compounds was evaluated using the microdilution broth method against eight strains of pathogenic fungi with fluconazole as positive control. According to the results of the target compounds, structure‐activity relationship (SAR) is summarized. The inhibitory activity against the tested strains of simplified compounds ( K01 — K16 ) has different levels improvement compared with compounds Z01 — Z29 . K01 — K16 showed significant antifungal activities against A. fumigatus, C. kruseii, and sensitive C. albicans 5314. Notably, compounds Z20 , Z22 , K10 , K11 and K16 also displayed different activities against two fluconazole‐resistance strains that were isolated from AIDS patients. The minimal inhibitory concentration (MIC) values against fluconazole‐resistant strains were in the range of 2—8 μg/mL and 4—32μg/mL, respectively. Furthermore, molecular docking was performed to investigate the binding affinities and interaction modes between the target compound and N‐myristoyltransferase.     

Identification and quantification of the volatile constituents in Cnidium monnieri using supercritical fluid extraction followed by GC‐MS

The volatile components of Cnidium monnieri were obtained by supercritical fluid extraction (SFE) and analyzed by GC‐MS (identification and determination of metabolites). The compounds were identified according to their retention times and mass spectra. The effects of different parameters, such as extraction pressure, temperature, dynamic extraction time, flow rate of CO₂, on the SFE of C. monnieri extracts were investigated. A total of 14 compounds of SFE extracts were identified. Osthole (69.52%), bornyl acetate (10.03%), α‐pinene (4.71%), and imperatorin (2.42%) were the major compounds identified in C. monnieri SFE extracts. The quantitation of osthole and imperatorin were then accomplished. The linear calibration ranges were all 5–1000 μg/mL for osthole and imperatorin by GC‐MS analysis. The recovery of osthole and imperatorin were in the range 96.5–101.8%. The LODs for osthole and imperatorin were 1.0 and 0.6 μg/mL, respectively.