Methanol Eluate Research Articles

Liquid Chromatographic Enantioseparation of Newly Synthesized Fluorinated Tryptophan Analogs Applying Macrocyclic Glycopeptides-Based Chiral Stationary Phases Utilizing Core-Shell Particles.

Due to the favorable features obtained through the incorporation of fluorine atom(s), fluorinated drugs are a group with emerging pharmaceutical importance. As their commercial availability is still very limited, to expand the range of possible candidates, new fluorinated tryptophan analogs were synthesized. Control of enantiopurity during the synthesis procedure requires that highly efficient enantioseparation methods be available. In this work, the enantioseparation of seven fluorinated tryptophans and tryptophan was studied and compared systematically to (i) develop analytical methods for enantioselective separations and (ii) explore the chromatographic features of the fluorotrytophans. For enantioresolution, macrocyclic glycopeptide-based selectors linked to core-shell particles were utilized, applying liquid chromatography-based methods. Application of the polar-ionic mode resulted in asymmetric and broadened peaks, while reversed-phase conditions, together with mobile-phase additives, resulted in baseline separation for all studied fluorinated tryptophans. The marked differences observed between the methanol and acetonitrile-containing eluent systems can be explained by the different solvation abilities of the bulk solvents of the applied mobile phases. Among the studied chiral selectors, teicoplanin and teicoplanin aglycone were found to work effectively. Under optimized conditions, baseline separations were achieved within 6 min. Ionic interactions were semi-quantitatively characterized and found to not influence enantiorecognition. Interestingly, fluorination of the analytes does not lead to marked changes in the chromatographic characteristics of the methanol-containing eluents, while larger differences were noticed when the polar but aprotic acetonitrile was applied. Experiments conducted on the influence of the separation temperature indicated that the separations are enthalpically driven, with only one exception. Enantiomeric elution order was found to be constant on both teicoplanin and teicoplanin aglycone-based chiral stationary phases (L < D) under all applied chromatographic conditions.

Antibacterial Activity of Endophytic Fungi Isolated from Bidara Roots (Ziziphus mauritiana Lam.) Against Bacteria That Cause Skin Infections Using TLC-Bioutography

One common disease found in tropical countries is skin infection. Inappropriate use of antibiotics to treat skin infections can lead to bacterial resistance, making it necessary to explore the source of bioactive compounds in natural materials. The Bidara plant (Ziziphus mauritiana Lam.) is known to have antibacterial properties. This research aimed to determine the antibacterial activity of endophytic fungal isolated from the parts of the Bidara plant against bacteria that cause skin infections using the TLC-Bioautography method. In this research, the isolate with the code IFAZ-6 was purified to obtain a pure endophytic fungal isolate, and macroscopic and microscopic examinations were conducted on that isolate. The obtained isolate was fermented for 21 days at room temperature using MYB (Maltose Yeast Broth) medium. The fermentation products were extracted using ethyl acetate (1:1). The obtained extract was further tested using TLC with a chloroform: methanol eluent (7:1). The TLC-Bioautography results showed Rf values of 0.81 and 0.58 indicating antibacterial activity against Staphylococcus aureus, Pseudomonas aeruginosa, Staphylococcus epidermidis, and Propionibacterium acnes bacteria. The identification of chemical components in the endophytic fungal isolate from the Bidara plant confirmed the presence of flavonoids, alkaloids, and anthraquinones. The extract from the endophytic fungal isolate with the code IFAZ-6 indicated antibacterial activity.

Potential of Endophyctic Fungi Isolates IFAZ-6 from Bidara Root (Ziziphus mauritiana Lam.) as Antibacterials Againts Digestive Tract Infection

Bidara root (Ziziphus mauritiana Lam.) has activity as an antibacterial against digestive tract infections. This study aims to determine the antibacterial activity of isolate IFAZ-6 endophytic fungi of bidara root against bacteria that cause digestive tract infections using the TLC-Bioautography method. Purification was conducted on the active isolate IFAZ-6 to obtain a pure endophytic fungi isolate. Subsequently, macroscopic and microscopic observations were carried out. Then, fermentation was performed in MYB (Maltose Yeast Broth) medium for 21 days. Screening and evaporation were conducted to produce an extract. The obtained extract was subjected to TLC analysis using a chloroform: methanol eluent (7:1). The TLC-Bioautography test was conducted against Escherichia coli, Salmonella typhi, Shigella dysentriae, and Vibrio cholerae bacteria. The TLC identification results showed one spot with an Rf value of 0.80 for the IFAZ-6 isolate. The chromatogram profile obtained from the TLC-Bioautography method for the IFAZ-6 isolate demonstrated antibacterial activity against bacteria that cause digestive tract infections.

Antibacterial Activity of Ethanol Extract of Sirih Cina Leaves (Peperomia pellucida) Using TLC-Bioautography and Agar Diffusion Methods

Sirih cina leaf (Peperomia pellucida) is a plant that contains active compounds of alkaloids, terpenoids, tannins, saponins, flavonoids and phenols that have potential antibacterial activity. This research aimed to determine the antibacterial activity of ethanol extract of sirih cina leaves (Peperomia pellucida) using the TLC-Bioautography and Agar Diffusion methods. Sirih cina leaf (Peperomia pellucida) was extracted by maceration and evaporated to obtain a thick extract. Screening test result showed that the extract was active at a concentration of 0.1% against the bacteria Propionibacterium acnes, Staphylococcus aureus and Pseudomonas aeruginosa. The results of antibacterial activity testing using the TLC-Bioautography method using the eluent methanol: chloroform (1:4) showed results with Rf values = 0.94, 0.80, 0.65, 0.54, 0.40, 0.30, 0.21, 0.10 against the bacteria Propionibacterium acnes, Staphylococcus aureus, and Pseudomonas aeruginosa. In determining the MIC, the value obtained was the same for the three test bacteria at a concentration of 0.5%, while the KBM value was at a concentration of 2% for Propionibacterium acnes bacteria, a concentration of 0.5% for Staphylococcus aureus bacteria, and a concentration of 1% for Pseudomonas aeruginosa bacteria. The results of antibacterial activity testing using the Agar Diffusion method obtained the largest inhibitory zone diameter at a concentration of 16% against Propionibacterium acnes bacteria with an inhibitory zone diameter of 23.20 mm, Staphylococcus aureus bacteria with an inhibitory zone diameter of 23.63 mm, and Pseudomonas aeruginosa bacteria with an inhibitory zone diameter. 24.48mm

Two-step dual-layer SPE method to separate antibacterial and antioxidant mushroom compounds

We developed a two-step dual-layer solid-phase extraction (SPE) method to separate and concentrate minor bioactive compounds of golden oyster mushroom (Pleurotus citrinopileatus) methanol extract. The mushroom extract is rich in fatty acids, including the highly abundant (20–35 %) and antibacterial linoleic acid. To eliminate the masking effect of linoleic acid in the bioassay, its removal was achieved by homemade dual-layer SPE that consisted of a lower C18 phase and an upper silica gel phase with the dried-on extract. In the first step the elution was performed with water (aqueous eluate), and then the dried C18 and silica gel phases were eluted separately with methanol (C18 methanol eluate and silica gel methanol eluate, respectively). Thin-layer chromatography (TLC)-effect-directed analysis demonstrated that the aqueous eluate contained sugars and antioxidants (TLC-DPPH); fatty acids were present in the silica gel methanol eluate, in the C18 methanol eluate the biologically active minor secondary metabolites were concentrated (TLC–Bacillus subtilis assay) beside 2 % remained linoleic acid according to HPLC-UV measurement. As a result, the antioxidant and antibacterial metabolites divided, and the low-abundant antibacterial compounds could be detected. Based on this study, the substance found at RF 0.25 by TLC-DPPH played the most significant role in generating the antioxidant effect of the aqueous eluate, equivalent to 5.07 ± 0.09 µg of gallic acid. Moreover, each SPE fraction and raw extract were tested for antibacterial effect using a microplate assay with a non-pathogenic Gram-positive Bacillus subtilis. The P. citrinopileatus extract (MIC-value – 50 µg/mL) and C18 methanol eluate (MIC-value - 25 µg/mL) inhibited the growth of B. subtilis while the other eluates did not.

High-temperature ultrafast ChipHPLC-MS

Herein, we present a miniaturized chip-based HPLC approach coupled to electrospray ionization mass spectrometry utilizing temperature to achieve high-speed separations. The approach benefits from the low thermal mass of the microfluidic chip and can form an electrospray from the pre-heated mobile phase. With the help of this technology, isothermal and temperature-programmable operations up to 130°C were pursued to perform reversed-phase separations of pesticides in methanol and ethanol-containing eluents in less than 20 s.Graphical

Identification of anti-tumor constituents from toad skin and toad venom by UPLC-QTOF/MS in-depth chemical profiling combined with bioactivity-based molecular networking

Toad skin (TS) and toad venom (TV) are two different traditional Chinese medicine (TCM) prepared from Bufo bufo gargarizans Cantor and Bufo melanostictus Schneider. Both of them were used in the treatment of ulcers, and now they are regarded as animal drugs with anti-tumor activity. However, the comparison analysis between their compositions and anti-tumor active ingredients has not been elucidated clearly. In this study, technology of ultra-performance liquid chromatography coupled with tandem quadrupole time-of-flight mass spectrometry (UPLC-QTOF/MS) and bioactivity-based molecular networking were applied to investigate the anti-tumor active ingredients of TS and TV. A method of collision energies-relied mass spectrometry combined with molecular networking was initially developed for identifying their chemical components. A combination of Cytoscape and molecular networking was then employed to analyze the prototype constitutes of TS absorbed in rat serum. In addition, cytotoxicity test was applied to evaluate their anti-proliferative activities against human gastric cancer (GC) cells. As a result, a total of 162 compounds were tentatively characterized, and four structural types existed in both TS and TV, including bufogenins, bufotoxins, indolealkylamines (IAAs), and acyl-arginine. Cyclic dipeptides could only be detected in TS, and the total number of bufogenins and bufotoxins in TV was higher than that of TS. Both of them significantly inhibited the viability of SGC7901 cells, and 70% methanol eluate of TS was the most potential active fraction. 44 prototype compounds in TS were identified, from which three types of potential tumor cytotoxic components, including bufogenins, IAAs, and cyclic dipeptides, were predicted. In human GC cells SGC7901, a mixture of nine bufogenins, including bufotalin, cinobufotalin, gamabufotalin, telocinobufagin, cinobufagin, bufarenogin, arenobufagin, hellebrigenin, and desacetylcinobufotalin, was conducted as bioactive components, which exerted a significant inhibitory effect on the cell viability of SGC7901 cells with a half maximal inhibitory concentration (IC50) value of 0.23 (0.19–0.27, 95%CI) μg/mL. Comparison of their chemical composition and anti-tumor activity reveals that TS might be able to partially replace TV, whilst bufogenins are the potential active ingredients.

A high-performance 3D phosphorus-doped graphene oxide adsorbent for imipramine wastewater treatment

The presence of pharmaceutical wastes in the environment has adversely impacted the marine biodiversity due to their hazardous and bioaccumulation nature. This research focussed on the development of an effective phosphorus-doped 3D graphene oxide with bentonite and carboxymethyl cellulose crosslinking (PG/BCC) for the removal of imipramine in wastewater. The impacts of single factor (adsorbent dosage, initial imipramine concentration, system temperature and contact time) on imipramine adsorption were examined by batch experiments while the interactive impacts of multiple factors and process optimisation were investigated by central composite design (CCD). The greatest adsorption capacity evaluated was 458.95 mg/g at the following CCD optimised operating parameters: 10 mg PG/BCC, 250 ppm initial concentration, 34 min contact time and 321 K temperature. The Langmuir model described well the equilibrium of imipramine adsorption whilst the pseudo-second-order model correlated closely to the kinetic data. The imipramine-PG/BCC system was spontaneous (-19.24 to −27.58 kJ/mol) and endothermic (1.23 to 14.56 kJ/mol) as evaluated from thermodynamic modelling. Characterisation of PG/BCC by various microscopy and spectroscopy analyses has validated the incorporation of imipramine into PG/BCC adsorbent. Regeneration of used PG/BCC was proven to be highly feasible with methanol eluent. Conclusively, the findings strongly advocate PG/BCC as a highly feasible and sustainable graphene-based adsorbent for imipramine separation from pharmaceutical wastewater.

Photochemical and bioactivity examination of fractionated saluang belum root extract (Lavanga sarmentosa) on in-vitro human sperm motility

Background: Saluang belum (Lavanga sarmentosa) is one of Kalimantan's typical plants, which is as efficacious as a traditional medicine to increase sexual activity and male fertility. Based on previous studies, the content of flavonoid and steroid in 70% ethanol extract of L. sarmentosa were able to affect sperm quality of mice. Studies related to L. sarmentosa are still limited for phytochemical test and their bioactivity on human spermatozoa motility in vitro.Objective: This study is to perform phytochemical tests of compound content in fractionation with eluents of high and low polarity, namely methanol and chloroform, and then to test their bioactivity on the motility of human spermatozoa in vitro.Methods: L. sarmentosa was extracted with 96% ethanol and fractionated by using a vacuum chromatography column with chloroform and methanol as the eluent. Then obtained samples were analysed by a quantitative phytochemical test. The samples used in-vitro human spermatozoa were divided into eleven groups: control group, group administered with L. sarmentosa extract eluent chloroform of 10, 50, 100, 500, and 1000 ng/mL, and same concentration with extract eluent methanol. Furthermore, the sperm motility was analysed by using a Computer Assisted Sperm Analyser (CASA). Results: The methanol and chloroform fraction of L. sarmentosa root extract contained metabolites, namely terpenoids, flavonoids, steroids, alkaloids, saponins, and tannins. The sperm motility increased significantly at the treatment group of the methanol and chloroform fractions compared to the control group. There was a significant difference between the sperm motility incubated with methanol and that with chloroform fraction at concentration 500 and 1000 ng/mL.Conclusion: The results of sperm motility were higher in the methanol fraction than those in the chloroform fraction.

Chemical constituents and antioxidant activity of Britton's wild petunia (Ruellia brittoniana) flower

Abstract. Sianturi GLR, Trisnawati EW, Koketsu M, Suryanti V. 2023. Chemical constituents and antioxidant activity of Britton's wild petunia (Ruellia brittoniana) flower. Biodiversitas 24: 3665-3672. Britton's wild petunia orkencana ungu (Ruellia brittoniana), which has purple flowers, is widely used as a decorative plant. Isolation and structure determination of the antioxidant compound of R. brittoniana flower were carried out. Extraction was carried out by maceration, and compound isolation was conducted by column chromatography. Structure elucidation was accomplished by FTIR, NMR, and MS Spectrometry. Apigenin (4',5,7-trihydroxyflavone) was isolated from the B1 fraction using chloroform: methanol (10: 1) eluent. Fraction A1, obtained from elution by chloroform: methanol (10: 0), consisted of 24 compounds. Two compounds were identified as 1-hexadecanol and 1-phenyl ethanone, which have antioxidant properties of fraction A1. Fraction B2 was eluted by chloroform: methanol (10:1), consisting of 20 compounds. A compound was identified as 2-methoxy phenol, contributingto the antioxidant properties of fraction B2. The total phenolic content of R. brittoniana flower extract was 1.033 mg GAE/g, and its total anthocyanin content was 16.97%. Fractions A1 and B2 possessed strong antioxidant activities due to their phenolic compounds. Apigenin has three -OH groups in the 4’, 5, and 7 positions; only the -OH group at the 4’ position contributes to its antioxidant activity. Therefore, apigenin has moderate antioxidant activity by DPPH assay. The modification structure of apigenin needs further study to enhance its antioxidant activity. This research shows that R. brittoniana flower can be a source of apigenin, also known to have anticancer properties.

Simultaneous adsorption of methylene blue and amoxicillin by starch-impregnated MgAl layered double hydroxide: Parametric optimization, isothermal studies and thermo-kinetic analysis

Textile and pharmaceutical effluents contain significant amounts of dyes and antibiotics, which pose a serious threat to the ecosystem when discharged directly. Therefore, they should be treated by facile treatment techniques using low-cost materials. Layered double hydroxide (LDH) and its hybrids have emerged as robust and economic adsorbents for water treatment. Herein, magnesium/aluminum LDH and its starch-based composite were synthesized by a co-precipitation technique. The physicochemical features of the developed adsorbents were thoroughly characterized using various analytical tools. The developed materials were tested for the eradication of methylene blue (MB) and amoxicillin (AMX) in batch mode adsorption by varying operating conditions. Adsorption performance depends on the solution's pH. Under optimum adsorption conditions of pH 11, adsorbent dosage of 50 mg/L, and treatment time of 120 min, starch-impregnated MgAl-LDH exhibited maximum MB and AMX adsorption capacities of 114.94 and 48.08 mg/g, respectively. The adsorption mechanism states that hydrogen bonds and weak van der Waals forces are responsible for the removal of pollutants by the developed materials. Moreover, equilibrium and kinetic studies revealed that the removal of dye and antibiotic followed the Freundlich and Langmuir models with the pseudo-second-order reaction kinetics, respectively. The spent adsorbents were regenerated using 0.1 M HCl (for MB) and methanol (for AMX) eluent, and reusability studies ensured that the developed adsorbents retained their performance for up to four consecutive adsorption/desorption cycles. MgAl-LDH and its starch-based hybrid could thus be used to effectively remove organic contaminants from wastewater streams on a commercial scale.

IDENTIFICATION OF ACTIVE CHEMICAL COMPONENTS OF ETHANOL EXTRACT OF PAINTED NETTLE LEAVES (COLEUS SCUTELLARIOIDES L. BENTH) AGAINST GASTROINTESTINAL INFECTION BACTERIA USING TLCBIOAUTOGRAPHY AND AGAR DIFFUSION METHOD

Infectious diseases are one of the public health problems caused by the transmission and multiplication of microorganisms. The research on the antibacterial activity of painted nettle leaves (Coleus scutellarioides L. Benth) extracts was carriedout to examine the activity and chemical components that provide inhibition against gastrointestinal infection bacteria. The extraction of painted nettles leaves performed maceration methd using a solvent of 96%. The extraction results were examined to determine the antibacterial activity at 1% concentration of the test bacteria: Escherichia coli, Salmonella thypi, and Shigella dysenteriae. The results showed that 96% ethanol extract of painted nettle leaves inhibited Escherichia coli, Salmonella thypi, and Shigella dysenteriae. The research conducted using agar diffusion indicated that painted nettleleaf extract showed activity against bacteria and had highly strong potential with diameters of 6-20 mm. The results of Thin Layer Chromatography (TLC) Bioautography test of ethanol extract of painted nettle leaves using chloroform:methanol eluent (3:1) showed inhibition of Escherichia coli, Shigella dysenteriae, and Salmonella thypi at Rf values of 0.90, 0.80, 0.56. Therefore, the identification test confirmed that the chemical componentsproviding antibacterial are from flavonoids, phenols, terpenoids, alkaloids, and steroidsKey words: Identification of chemical components, painted nettle leaves, gastrointestinal bacteria, TLC-Bioautography and Agar diffusion

Features of the Dependence of the Retention Indices of Sorbates in Reversed-Phase High-Performance Liquid Chromatography on the Content of Organic Solvents in the Eluent

Characterizing the dependence of the retention indices (RIs) of sorbates of different chemical origins on the content (С) of organic solvents (methanol, acetonitrile) in eluents used in reversed-phase HPLC shows that the coefficients dRI/dC of the same compounds for eluents of different compositions differ considerably. The range of variations in coefficients dRI/dC for water–methanol eluents (–5.6 to +4.6) is approximately twice that of water–acetonitrile eluents (−4.5 to +0.8). It is also found that for nonpolar compounds when using water–acetonitrile eluents, the dRI/dC values are typically lower than those for water–methanol eluents. The opposite is observed for polar compounds. The signs and absolute values of coefficients dRI/dC are largely determined by the polarity of the sorbates. dRI/dC 0 for nonpolar sorbates, and dRI/dC 0 for sorbates of higher polarity. Determination even of the sign of this coefficient therefore provides important information about the chemical nature of sorbates. It is shown that coefficients dRI/dC do not correlate with either the RI values or hydrophobicity logPlog⁡. However, they do correlate with homologous increments of hydrophobicity ilogP and the homologous increments of RI iRI for eluents of any composition. Quantities ilogP and iRI characterize the polarity of homologous series of sorbates, rather than the polarity of the particular sorbates.

Analisis Kadar Kurkumin pada Herbal Oil Kunyit Ekstrak Virgin Coconut Oil dengan Metode Ultrasonik dan Maserasi

Vegetable oil theoretically and experimentally has proven its potential as an alternative solvent in the extraction of natural materials. Turmeric infused with virgin coconut oil (VCO) is a way to take advantage of the active compounds from the herbs and the oil itself. This study aims to determine the ability of the VCO solvent in extracting curcumin compounds from turmeric with the addition of tween 80 surfactants. The extraction method used was maceration at 60℃ and an ultrasonic frequency of 40 kHz for 15 minutes. Thin layer chromatography (TLC) was used for qualitative analysis of each herbal oil extract using chloroform: methanol (95:5) eluent and FTIR spectrophotometer to identify functional groups. The highest curcumin content was found in herbal oil with tween 80 of 2 ml, namely 31 ppm in maceration extraction and 260.7 ppm in ultrasonic extraction. Identification of curcumin functional groups in herbal oils showed absorption patterns of O-H, C=O, aromatic C=C, C-O-C, and C-H.

Preparation and application of novel thermo-sensitive molecularly imprinted polymer for selective extraction of omeprazole from pharmaceutical formulation and biological fluids

ABSTRACT Omeprazole selective molecularly imprinted polymer was synthesized by polymerization using 2-hydroxyethyl methacrylate as a monomer, N-vinylcaprolactam as a thermo-sensitive polymer, and N, N′-methylenebisacrylamide as cross-linker, respectively. This study aimed to develop a novel polymer as a nanoadsorbent for the extraction of omeprazole in biological and pharmaceutical samples. To achieve maximum extraction recovery of the drug, the Nd:YAG pulsed laser irradiation was used to convert adsorbent particles into smaller sizes using water solvent at different irradiation times. Properties of prepared thermo-sensitive molecularly imprinted polymer were characterized by different analyses. The optimal extraction conditions were thermo-sensitive molecularly imprinted polymer dosage of 0.01 g, a cross-linking agent of 0.15 g, contact time of 15 min, eluent of methanol, the temperature of 25°C, initial drug concentration of 20 mg L−1, and solution pH of 4. The sorption isotherms and selective recognition of thermo-sensitive molecularly imprinted polymer were investigated in detail. Sorption results fitted well into the linearized Langmuir equation. The selectivity experiment has shown that the sorption capacity and selectivity of thermo-sensitive molecularly imprinted polymer to omeprazole were higher than those of bicalutamide and prednisolone. A high-performance liquid chromatography-ultra-violet detector method was validated and utilized for analysis of drug extracted from biological and pharmaceutical samples. The method was linear in the range of 0.5–80 mg L−1 with a relative standard deviation value of 0.094 and a limit of detection and a limit of quantification of 0.9 and 30 µg L−1, respectively. The recovery of omeprazole drug ranged from 94.3%, 99.2%, and 98.1%, respectively, in human plasma, human urine, and pharmaceutical samples.

Cytotoxicity and reactive oxygen species production induced by different co-monomer eluted from nanohybrid dental composites

BackgroundSafety issues for dental restorative composites are critical to material selection, but, limited information is available to dental practitioners. This study aimed to compare the chemical and biological characteristics of three nanohybrid dental composites by assessing filler particle analysis, monomer degree of conversion (DC), the composition of eluates, and cytotoxicity and reactive oxygen species (ROS) production in fibroblasts.MethodsThree nanohybrid composites (TN, Tetric N-Ceram; CX, Ceram X Sphere Tec One; and DN, DenFil NX) were used. The size distribution and morphology of the filler particles were analysed using scanning electron microscopy (n = 5). The DC was measured via micro-Raman spectroscopy (n = 5). For the component analysis, methanol eluates from the light-polymerised composites were evaluated by gas chromatography/mass spectrometry (n = 3). The eluates were prepared from the polymerised composites after 24 h in a cell culture medium. A live/dead assay (n = 9) and Water-Soluble Tetrazolium-1 assay (n = 9) were performed and compared with negative and positive controls. The ROS in composites were compared with NC. Statistical significance in differences was assessed using a t-test and ANOVA (α = 0.05).ResultsMorphological variations in different-sized fillers were observed in the composites. The DC values were not significantly different among the composites. The amounts of 2-hydroxyethyl methacrylate (HEMA) were higher in TN than DN (p = 0.0022) and triethylene glycol dimethacrylate (TEGDMA) in CX was higher than in others (p < 0.0001). The lowest cell viability was shown in CX (p < 0.0001) and the highest ROS formation was detected in TN (p < 0.0001).ConclusionsThree nanohybrid dental composites exhibited various compositions of filler sizes and resin components, resulting in different levels of cytotoxicity and ROS production. Chemical compositions of dental composites can be considered with their biological impact on safety issues in the intraoral use of dental restorative composites. CX with the highest TEGDMA showed the highest cytotoxicity induced by ROS accumulation. DN with lower TEGDMA and HEMA presented the highest cell viability.

Aktivitas Antibakteri Ekstrak Kulit Batang Tumbuhan Johar (Senna siamea Lam) pada Berbagai Polaritas Pelarut

Johar plant is a type of plant from the Fabaceae family which is widely used in traditional medicine such as malaria, itching and diabetes medicine. This study aims to determine the antibacterial activity of Johar stem bark extract with different levels of solvent polarity on the growth of Staphylococcus aureus and Escherichia coli bacteria and to determine the active compound class by TLC-Bioautography. The extraction of active compounds used a multilevel maceration method starting with n-hexane (non polar), followed by ethyl acetate (semi-polar) and ethanol (polar) solvents. Antibacterial activity testing was carried out by diffusion well method with a concentration variant of 25% and 50%. The results showed that n-hexane, ethyl acetate, and ethanol extract had antibacterial activity against the two test bacteria. Ethyl acetate and ethanol extract from Johar stem bark at a concentration of 50% were classified as very strong antibacterials with inhibition zone diameters against S. aureus, which were 22.02±0.84 mm and 20.16±0.23 mm, respectively. The results of the TLC-Bioautography test showed that the three test extracts had strong antibacterial activity against S. aureus and E. coli. In the n-hexane extract with n-hexane: ethyl acetate (9:1) eluent using Lieberman-Burchard spray reagent, it was suspected that triterpenoid compounds were present. In ethyl acetate extract with n-hexane: ethyl acetate (6:4) eluent and ethanol extract with chloroform: methanol (8:2) eluent using FeCl3 1% spray reagent, it was suspected that the tannin compound was present in both extracts.

Validated single urinary assay designed for exposomic multi-class biomarkers of common environmental exposures.

Epidemiological studies often call for analytical methods that use a small biospecimen volume to quantify trace level exposures to environmental chemical mixtures. Currently, as many as 150 polar metabolites of environmental chemicals have been found in urine. Therefore, we developed a multi-class method for quantitation of biomarkers in urine. A single sample preparation followed by three LC injections was optimized in a proof-of-approach for a multi-class method. The assay was validated to quantify 50 biomarkers of exposure in urine, belonging to 7 chemical classes and 16 sub-classes. The classes represent metabolites of 12 personal care and consumer product chemicals (PCPs), 5 polycyclic aromatic hydrocarbons (PAHs), 5 organophosphate flame retardants (OPFRs), 18 pesticides, 5 volatile organic compounds (VOCs), 4 tobacco alkaloids, and 1 drug of abuse. Human urine (0.2 mL) was spiked with isotope-labeled internal standards, enzymatically deconjugated, extracted by solid-phase extraction, and analyzed using high-performance liquid chromatography-tandem mass spectrometry. The methanol eluate from the cleanup was split in half and the first half analyzed for PCPs, PAH, and OPFR on a Betasil C18 column; and pesticides and VOC on a Hypersil Gold AQ column. The second half was analyzed for tobacco smoke metabolites and a drug of abuse on a Synergi Polar RP column. Limits of detection ranged from 0.01 to 1.0 ng/mL of urine, with the majority ≤0.5 ng/mL (42/50). Analytical precision, estimated as relative standard deviation of intra- and inter-batch uncertainty, variabilities, was <20%. Extraction recoveries ranged from 83 to 109%. Results from the optimized multi-class method were qualified in formal international proficiency testing programs. Further method customization options were explored and method expansion was demonstrated by inclusion of up to 101 analytes of endo- and exogenous chemicals. This exposome-scale assay is being used for population studies with savings of assay costs and biospecimens, providing both quantitative results and the discovery of unexpected exposures.

Analytical aspects of organic compounds retention indices dependence in reversed phase HPLC on the content of methanol in eluent

As a result of the determination of retention indices (RI) of 11 organic compounds of various polarity in reversed phase (RP) HPLC using methanol as organic solvent in elu­ent, the coefficients of the dependence of RI vs. content of methanol, dRI/dС were de­ter­mi­ned. Formally, these parameters are equivalent to the temperature coefficients of gas chromatographic retention indices, b = dRI/dT. It is shown that the ranges of variations of these coefficients are rather large (from -2.0 up to +4.6 in the current work), which requires re­ve­­a­ling the factors influencing their signs and absolute values. The correlations of coeffi­ci­­ents dRI/dC with retention indices themselves, as well as with hydrophobicity factors, logP (the logarithms of partition coefficients in the system 1-octanol/water) seem to be negligible. The best correlations of dRI/dC were observed with such polarity mea­su­res of organic compounds as homologous increments of hydrophobicity factors (ilogP), and re­ten­tion indices (iRI). Such transformations of pro­perties A as their homologous increments characterize different homologues despite of their locations within the homologous series. Thus, the parameters ilogP and iRI appeared to be the measures of the polarity of the corres­pon­­ding series. This approach per­mits us to reveal that the dependence of retention indices in RP HPLC on the content of me­tha­nol in eluent is determined just by the analytes¢ po­la­rity and their hydrophobic – hydrophilic proper­ties. The ratio dRI/dC &gt; 0 is typi­cal for non-polar analytes, while for polar compo­unds the negative signs of these coeffi­ci­ents are typical, dRI/dC &lt; 0. Hence, deter­mining even the sign of this coefficient provi­des the important information on the chemical origin of analytes.

In-situ decomposed nanofluids dispersive liquid-phase microextraction for detection of seven triazole fungicidets in fruit juices and tea drinks

A novel, eco-friendly and efficient in-situ decomposed nanofluid dispersive liquid-phase microextraction approach was developed to detect myclobutanil, flusilazole, hexaconazole, penconazole, epoxiconazole, paclobutrazol and diniconazole in tea drinks and fruit juices by high-performance liquid chromatography. Various new nanofluids were prepared physically using multi-walled carbon nanotubes and hydrophilic deep eutectic solvents, with acetic acid/ DL-lactic acid/glycerol/propylene glycol/ethylene glycol/urea and choline chloride used as the hydrogen-bond donor and acceptor respectively. The nanofluids in the sample solutions were decomposed in-situ, while multi-walled carbon nanotubes and deep eutectic solvents served as the adsorbent and carrier/stabilizer/dispersing agent, respectively. One-factor-at-a-time tests showed the optimized parameters for extracting triazole fungicides were 10 mL and pH 6 of sample solutions, 300 μL of nanofluids ([choline chloride: ethylene glycol]: multi-walled carbon nanotubes = [1:2] : 20), 8% sodium chloride, 9 min of vortex, 5 min of centrifugation, 1000 μL of eluent methanol, and 2 min of elution. The new approach performed well with linear range, relative recovery, detection limit, quantification limit, and inter- and intra-day relative standard deviations of 10-10000 μg/L, 70.03-107.14%, 3.34-8.30 μg/L, 10-25 μg/L, < 11.30% and <13.01%, respectively. The adsorption isotherms of triazole fungicides were well fitted by a Freundlich model and a pseudo-second-order kinetic model, revealing that the adsorption process accorded with the theories of multilayer adsorption and chemical adsorption. This environmental approach can triumphantly detect residual triazole fungicides in real tea drinks and fruit juices, and is a potentially promising technique for detecting food matrices.