scholarly journals Photocatalytic removal of fluoroquinolones and their antimicrobial activity from water matrices at trace levels: a comparison of commercial TiO2 catalysts

2018 ◽  
Vol 78 (8) ◽  
pp. 1668-1678 ◽  
Author(s):  
Wilson Augusto Lima Venancio ◽  
Caio Rodrigues-Silva ◽  
Milena Guedes Maniero ◽  
José Roberto Guimarães
Keyword(s):  
Antimicrobial Activity ◽  
Biological Activity ◽  
High Performance ◽  
Photocatalytic Oxidation ◽  
Antimicrobial Agents ◽  
Solid Phase ◽  
Tap Water ◽  
Uva Irradiation ◽  
The Matrix ◽  
Resultant Solution

Abstract In this study, a solution containing the fluoroquinolones (FQs) ciprofloxacin, lomefloxacin, and ofloxacin (antimicrobial agents) was subjected to photocatalytic oxidation under UVA irradiation, employing the commercial titanium dioxide as catalyst. On-line solid phase extraction coupled to ultra-high-performance liquid chromatography–mass spectroscopy was used to pre-concentrate and quantify the analytes. The process provided an almost 95% degradation efficiency for all the FQs. The TiO2 PC500 (100% anatase) was more efficient than TiO2 P25 (80% anatase) for FQs degradation. The matrix effect on the efficiency of the process was evaluated by ultrapure water – UW, simulated water – SW, bottled water –BW, and public drinking tap water – TW. Simulated water showed lower interference, compared to drinking water and bottled mineral water, due to the lower concentrations of hydroxyl radical scavengers. The assessment of the residual antimicrobial activity in the solution, when using 50 mg L−1 PC500 or 100 mg L−1 P25, showed reductions of biological activity (after 120 min of reaction) of 92.4% and 95.4% for Escherichia coli, and 78.1% and 84.2% for Bacillus subtilis, respectively. It shows that the photocatalytic oxidation process was able to not only degrade the FQs but also deactivate its biological activity in the resultant solution.

scholarly journals Effects of Dimerization on the Structure and Biological Activity of Antimicrobial Peptide Ctx-Ha

2012 ◽  
Vol 56 (6) ◽  
pp. 3004-3010 ◽  
Author(s):  
E. N. Lorenzón ◽  
G. F. Cespedes ◽  
E. F. Vicente ◽  
L. G. Nogueira ◽  
T. M. Bauab ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Biological Activity ◽  
Antimicrobial Peptide ◽  
Hemolytic Activity ◽  
Pore Diameter ◽  
Solid Phase ◽  
Biological Activities ◽  
Solid Phase Peptide Synthesis ◽  
Activity Assay ◽  
Growth Of Bacteria

ABSTRACTIt is well known that cationic antimicrobial peptides (cAMPs) are potential microbicidal agents for the increasing problem of antimicrobial resistance. However, the physicochemical properties of each peptide need to be optimized for clinical use. To evaluate the effects of dimerization on the structure and biological activity of the antimicrobial peptide Ctx-Ha, we have synthesized the monomeric and three dimeric (Lys-branched) forms of the Ctx-Ha peptide by solid-phase peptide synthesis using a combination of 9-fluorenylmethyloxycarbonyl (Fmoc) andt-butoxycarbonyl (Boc) chemical approaches. The antimicrobial activity assay showed that dimerization decreases the ability of the peptide to inhibit growth of bacteria or fungi; however, the dimeric analogs displayed a higher level of bactericidal activity. In addition, a dramatic increase (50 times) in hemolytic activity was achieved with these analogs. Permeabilization studies showed that the rate of carboxyfluorescein release was higher for the dimeric peptides than for the monomeric peptide, especially in vesicles that contained sphingomyelin. Despite different biological activities, the secondary structure and pore diameter were not significantly altered by dimerization. In contrast to the case for other dimeric cAMPs, we have shown that dimerization selectively decreases the antimicrobial activity of this peptide and increases the hemolytic activity. The results also show that the interaction between dimeric peptides and the cell wall could be responsible for the decrease of the antimicrobial activity of these peptides.

Flumethrin Residue Levels in Honey from Apiaries of China by High-Performance Liquid Chromatography

2015 ◽  
Vol 78 (1) ◽  
pp. 151-156 ◽  
Author(s):  
L. S. YU ◽  
F. LIU ◽  
H. WU ◽  
H. R. TAN ◽  
X. C. RUAN ◽  
...  
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
High Performance ◽  
Solid Phase ◽  
Extraction Column ◽  
Uv Detector ◽  
Promising Alternative ◽  
Rotary Evaporation ◽  
The Matrix ◽  
Pretreatment Conditions

A method for detection of flumethrin residue in honey by high-performance liquid chromatography was established. After n-hexane–dichloromethane (4:6, vol/vol) extraction, the honey samples were concentrated by rotary evaporation, purified by an Oasis HLB solid-phase extraction column, and detected using a UV detector at 267 nm. The interference of the matrix was greatly reduced by optimizing pretreatment conditions; thus, the minimal detection limit of cyhalothrin was 0.005 mg/kg, the average recovery was 80.8 to 96.8%, and the coefficient of variation was 0.6 to 1.5%. The precision and reproducibility of this method was suitable and applicable for detecting flumethrin residue in honey. With this method, 135 honey samples from seven locations in the People's Republic of China were tested; 77 samples tested positive for flumethrin residue, resulting in a detection rate of 75.3%. Samples from the Guangdong province had the highest flumethrin residue level (0.122 mg/kg) of the locations tested. On the basis of analytical validation, the high-performance liquid chromatography has been shown to be a promising alternative for the analysis of flumethrin residue in honey samples.

scholarly journals Alginate-Graphene Oxide Biocomposite Sorbent for Rapid and Selective Extraction of Non-Steroidal Anti-Inflammatory Drugs Using Micro-Solid Phase Extraction

2019 ◽  
Vol 19 (3) ◽  
pp. 684 ◽  
Author(s):  
Mohammad Salim Tabish ◽  
Nor Suhaila Mohamad Hanapi ◽  
Wan Nazihah Wan Ibrahim ◽  
Nor’ashikin Saim ◽  
Noorfatimah Yahaya
Keyword(s):  
Graphene Oxide ◽  
Solid Phase Extraction ◽  
Electrostatic Interactions ◽  
High Performance ◽  
Solid Phase ◽  
Tap Water ◽  
Phase Extraction ◽  
Composite Sorbent ◽  
Inflammatory Drugs ◽  
Anti Inflammatory

In this work, a bio-composite sorbent, alginate incorporated graphene oxide (Alg/GO) is prepared for the micro solid phase extraction of non-steroidal anti-inflammatory drugs (NSAIDs) from water samples. The sorbent was prepared in a suspended solution form at a ratio of 0.3:1 (w/v %) of graphene oxide (GO) and alginate (Alg). The chemical structure, morphology and surface area of the composite beads were characterized using Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM) and Brunauer–Emmett–Teller (BET). GO showed good miscibility and well dispersion through intermolecular hydrogen bonds and electrostatic interactions within the Alg matrix. The synthesized sorbent was applied for the determination of the selected drugs in a tap water sample using micro-solid phase extraction technique and was analyzed by high-performance liquid chromatography-ultraviolet detector (HPLC-UV). The results showed good linearity in the range of 10–1000 µg L–1 with correlation coefficients (r ≥ 0.9979), low detection limits (LOD) between 3.1–4.6 µg L–1, excellent relative recoveries in the range of 99.6–102.1% and good reproducibility (RSD ≤ 3.9%). Thus, these validated results showed that Alg/GO could be potential and useful as a bio-composite sorbent for micro-solid phase extraction for the analysis of targeted drugs from aqueous matrices.

scholarly journals Synthesis and Biological Studies on (KLAKLAK)2-NH2 Analog Containing Unnatural Amino Acid β-Ala and Conjugates with Second Pharmacophore

Molecules ◽  
2021 ◽  
Vol 26 (23) ◽  
pp. 7321
Author(s):  
Sirine Jaber ◽  
Veronica Nemska ◽  
Ivan Iliev ◽  
Elena Ivanova ◽  
Tsvetelina Foteva ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Antimicrobial Agents ◽  
Solid Phase ◽  
Hydrolytic Stability ◽  
Solid Phase Peptide Synthesis ◽  
Unnatural Amino Acid ◽  
The Body ◽  
Diffusion Method ◽  
Anticancer Properties ◽  
Biological Studies

(1) Background: Peptides are good candidates for anticancer drugs due to their natural existence in the body and lack of secondary effects. (KLAKLAK)2 is an antimicrobial peptide that also shows good anticancer properties. (2) Methods: The Solid Phase Peptide Synthesis (Fmoc-strategy) was used for the synthesis of target molecules, analogs of (KLAKLAK)2-NH2. The purity of all compounds was monitored by HPLC, and their structures were proven using mass spectrometry. Cytotoxicity and antiproliferative effects were studied using 3T3 NRU and MTT tests, respectively. For determination of antimicrobial activity, the disc-diffusion method was used. Hydrolytic stability at three pH values, which mimic the physiological pH in the body, was investigated by means of the HPLC technique. (3) Results: A good selective index against MCF-7 tumor cell lines, combined with good cytotoxicity and antiproliferative properties, was revealed for conjugates NphtG-(KLAKLAK)2-NH2 and Caf-(KLAKLAK)2-NH2. The same compounds showed very good antifungal properties and complete hydrolytic stability for 72 h. The compound Caf-(KLβ-AKLβ-AK)2-NH2 containing β-Ala in its structures exhibited good antimicrobial activity against Escherichia coli K12 407 and Bacillus subtilis 3562, in combination with very good antiproliferative and cytotoxic properties, as well as hydrolytic stability. (4) Conclusions: The obtained results reveal that all synthesized conjugates could be useful for medical practice as anticancer or antimicrobial agents.

scholarly journals Detecção de Resíduos de Agrotóxicos no Mel de Abelha

2014 ◽  
Vol 2 (2) ◽  
pp. 17
Author(s):  
F. M. Silva ◽  
D. C. Coelho ◽  
A. V. Machado ◽  
R. O. Costa
Keyword(s):  
Gas Chromatography ◽  
Liquid Chromatography ◽  
Pesticide Residues ◽  
High Performance ◽  
Solid Phase ◽  
Foreign Market ◽  
Extraction Methods ◽  
Uv Detector ◽  
Residue Detection ◽  
The Matrix

<p>As abelhas A. melífera são uns dos mais importantes polinizadores de culturas, além disso, elas produzem mel, própolis, geleia real e cera. O mel, principal produto da atividade apícola, utilizado como alimento, adoçante e para fins terapêuticos (apiterapia), tem a imagem de ser natural, saudável e limpo sendo esse um produto muito valorizado no mercado externo por isso, a busca por rigorosos padrões de qualidade se torna necessária para atender a um mercado consumidor cada vez mais exigente. Dessa forma a identificação da origem floral e geográfica, a ocorrência de adulterações e as contaminações, principalmente com antibióticos e agrotóxicos no mel tem se tornado uma rota importante devido os quais podem acarretar problemas de saúde ao consumidor. A dispersão da matriz em fase sólida (MSPD) combinada às técnicas cromatográficas modernas como cromatografia a gás (GC) e cromatografia a líquido (HPLC) é uma alternativa para evitar os diversos inconvenientes encontrados nos métodos clássicos de extração. A proposta desse trabalho foi pesquisar os diferentes tipos de Análises e metodologias de detecção de resíduos de agrotóxicos no mel de abelha Apresentando diferentes metodologias para a execução de estudos para validação de metodologia em métodos analítico, utilizando as técnicas de dispersão da matriz em fase sólida, cromatografia a gás acoplada à espectrometria de massas e cromatografia líquida de alta eficiência com detector espectrofotométrico com arranjo de diodos.</p><p><strong>Pesticide Residues in Honey Pesticide Residues detection in Bee honey</strong></p><pre> </pre><p><strong> </strong>A. mellifera bees are one of the most important pollinators of crops in addition they produce honey, propolis, royal jelly and wax. Honey, the main product of beekeeping, used as food, sweetener and in therapy (apitherapy), has the image of being natural, healthy and clean making a highly valued product in the foreign market so the search for rigorous standards of quality is needed to meet a consumer market increasingly demanding. Thus the identification of floral and geographical origin, the occurrence of tampering and contamination, especially with antibiotics and pesticides in honey has become an important route because which can cause health problems to consumers. The dispersion of the solid phase matrix (PDDM) combined with modern chromatographic techniques as gas chromatography (GC) and liquid chromatography (HPLC) is an alternative to avoid the various drawbacks found in classical extraction methods. The purpose of this study was to investigate the different types of analyzes and pesticide residue detection methodologies in honey Introducing different methodologies for carrying out studies for validation of a method in analytical methods, using the matrix dispersion techniques in solid phase, gas chromatography coupled to mass spectrometry and high-performance liquid chromatography with UV detector with diode array.</p>

scholarly journals Synthesis and Biological Activity of 1,2,4-Triazolo-[3,4-b]Thiadiazole as Antimicrobial Agents

2014 ◽  
Vol 26 ◽  
pp. 45-52
Author(s):  
Piyush B. Vekariya ◽  
Jalpa R. Pandya ◽  
Vaishali Goswami ◽  
Hitendra S. Joshi
Keyword(s):  
Antimicrobial Activity ◽  
Antibacterial Activity ◽  
Spectral Analysis ◽  
Biological Activity ◽  
Antimicrobial Agents ◽  
Dilution Method ◽  
Mass Spectral Analysis ◽  
Mass Spectral ◽  
Broth Dilution

Some novel 6-fluoro chroman derivatives having 1,2,4-triazolo-[3,4-b]thiadiazole were synthesized and characterized by IR, NMR and mass spectral analysis. All synthesized compounds were screened for antimicrobial activity using broth dilution method. All the compounds showed good antimicrobial activity and compound 5e showed significant antibacterial activity.

scholarly journals Synthesis, Physical Characterization and Biological Activity of Some Schiff Base Complexes

2008 ◽  
Vol 5 (3) ◽  
pp. 620-626 ◽  
Author(s):  
R. Rajavel ◽  
M. Senthil Vadivu ◽  
C. Anitha
Keyword(s):  
Antimicrobial Activity ◽  
Biological Activity ◽  
Schiff Base ◽  
Organic Molecule ◽  
Structural Modification ◽  
Antimicrobial Agents ◽  
Biological Activities ◽  
Molar Conductance ◽  
Molar Conductivity ◽  
Schiff Base Complexes

Structural modification of organic molecule has considerable biological relevance. Further, coordination of a biomolecules to the metal ions significantly alters the effectiveness of the biomolecules. In view of the antimicrobial activity ligand [bis-(2-aminobenzaldehyde)] malonoyl dihydrazone], metal complexes with Cu(II), Ni(II), Zn(II) and oxovanadium(IV) have been synthesized and found to be potential antimicrobial agents. An attempt is also made to correlate the biological activities with geometry of the complexes. The complexes have been characterized by elemental analysis, molar conductance, spectra and cyclicvoltammetric measurements. The structural assessment of the complexes has been carried out based on electronic, infrared and molar conductivity values.

scholarly journals Determination of Synthetic Hormones in Animal Urine by High-Performance Liquid Chromatography/Mass Spectrometry

2007 ◽  
Vol 90 (2) ◽  
pp. 626-632 ◽  
Author(s):  
Antoni Rbies ◽  
Albert Cabrera ◽  
Francesc Centrich
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
High Performance ◽  
Solid Phase ◽  
The European Union ◽  
Liquid Chromatography Mass Spectrometry ◽  
Triple Quadrupole Mass Spectrometer ◽  
The Matrix ◽  
Synthetic Hormones

Abstract A method was developed for the extraction of stanozolol, taleranol, zeranol, hexestrol, dienestrol, ethynylestradiol, diethylstilbestrol, and trenbolone from animal urine. The analytes were extracted from the matrix by enzymatic hydrolysis, solid-phase extraction, and liquidliquid extraction. Detection and quantitation were performed on a high-performance liquid chromatography system coupled to a triple quadrupole mass spectrometer. The identification criteria met the European Union regulations. Validation of this method established a decision limit between 0.2 and 0.9 μg/L and a detection capability between 0.3 and 1.0 μg/L, depending on the analyte.

scholarly journals Impact of Different Extraction Methods on Furanosesquiterpenoids Content and Antibacterial Activity of Commiphora myrrha Resin

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Ali S. Alqahtani ◽  
Rashed N. Herqash ◽  
Omar M. Noman ◽  
Md. Tabish Rehman ◽  
Abdelaaty A. Shahat ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Silica Gel ◽  
High Performance ◽  
Antimicrobial Agents ◽  
Solid Phase ◽  
Dna Gyrase ◽  
Extraction Methods ◽  
Sample Extraction ◽  
Relative Standard ◽  
Key Residues

The oleo-gum-resin of Commiphora myrrha is one of the most known natural antimicrobial agents, mainly due to its furanosesquiterpenes. A validated method based on sample extraction by matrix solid-phase dispersion (MSPD) followed by high-performance column chromatography (HPLC) determination is applied to analyze two furanosesquiterpenoids, namely, 2-methoxyfuranodiene (CM-1) and 2-acetoxyfuranodiene (CM-2), existing in C. myrrha. The trial parameters that controlled the extraction prospective were studied and optimized. These include the nature of dispersant, mass ratio of sample to the dispersant, and the volume of elution solvent. A comparative antimicrobial study that used the Minimum Inhibitory Concentration Assay (MIC) method between MSPD, ultrasonic, and Soxhlet of myrrh extracts was also conducted. The optimal MSPD parameters used were (i) 15 mL of methanol applied as elution solvent; (ii) silica gel/sample mass at a 2 : 1 ratio; and (iii) a dispersing sorbent selected as silica gel. Technique retrievals were regulated from 96.87% to 100.54%, with relative standard deviations (RSDs) from 1.24% to 4.45%. Commiphora myrrha-MSPD (CM-MSPD) extract showed the highest antibacterial activity against gram-positive and gram-negative bacteria (156.25 μg/mL and 312.5 μg/mL, respectively) and antifungal activity (156.25 μg/mL). Yields acquired through the MSPD technique were larger than yields from other extraction techniques (sonication and traditional reflux extraction methods) with less consumption of time, sample, and solvent. The mode of antibacterial action of CM-1 and CM-2 was elucidated by performing molecular docking with bacterial DNA gyrase. Both the compounds interacted with key residues of DNA gyrase.

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