Journal of the Serbian Chemical Society

Investigation of the bioactivities of Saponaria mesogitana methanolic extract along with its phytochemical composition

2024-10-03T07:12:53+02:00

Saponaria species are known to contain saponins which have a wide variety of biological activities. But up to now, the phenolic compounds of Saponaria mesogitana have not been clarified. Therefore, this study aimed to determine the phenolic composition and some biological activities of S. mesogitana for the first time. The antioxidant activities of the methanol and water extracts were assessed using the DPPH, FRAP and β-carotene/linoleic acid assays, while the total secondary metabolite content, including phenolics, flavonoids and saponins, was also determined for both extracts. Based on the antioxidant activity and total phenolic and flavonoid contents, further HPLC analysis, as well as anticancer and antimicrobial activity experiments, were conducted using the methanol extract. The anticancer potential was assessed using the MTT assay and wound healing migration test, while antibacterial activity was evaluated through disc diffusion and MIC assays. Additionally, the antibiofilm properties of the extract were examined using the crystal violet method. The methanolic extract showed high antioxidant activity, while caffeic acid and epicatechin were characterized as major phenolic compounds by HPLC. S. mesogitana inhibited not only bacterial growth but also the levels of migration of SHSY-5Y cancer cells. These findings indicate that S. mesogitana possesses potent antioxidant, anticancer, antimicrobial and antibiofilm activities associated with its bioactive phenolic constituents.

Coating technology on mortar surface for extending service life of on-site building construction

2024-06-18T10:58:49+02:00

The superhydrophobic, self-cleaning and anti-corrosion surface was successfully coated on mortar using an effective one-step spray coating technique. A coating solution was prepared by mixing methyltrichlorosilane-modified SiO₂/TiO₂ nanoparticles at different ratios to enhance the superhydrophobicity and reduce water absorption of the mortar. The sample prepared using a SiO₂/TiO₂ with the ratio of 75/25 was found to be optimal, exhibiting a high water contact angle and low sliding angle, which resulted in a reduction of water absorption by more than 97.5 % and chloride ion penetration depth. Furthermore, the robustness of the superhydrophobic coating was analyzed against various tests including water drop impact, sand abrasion impact, tape peeling and sandpaper abrasion tests, each test was conducted with over 10000 drops, 300 g, 60 cycles and 5 cycles, respectively. Notably, the coating showed excellent water absorption reduction of 82.6 % after sandpaper abrasion for a length of 200 cm (20 cycles), even though the water contact angle was reduced to 118°. Thus, the fabrication of superhydrophobic mortar surface offers a novel, alternative approach that is simple, efficient, cost-effective and provides multifunction protection surface to increase the service life of on-site building construction with enhanced mechanical durability and anti-corrosion properties.

Application of magnetite nanoparticle-modified walnut shell as an adsorbent for the removal of the organic dye Coomassie Brilliant Blue R-250

2024-09-23T23:04:54+02:00

In this research, a magnetic nanocomposite, walnut shell@Fe₃O₄, was synthesized as a natural adsorbent for the removal of Coomassie Brilliant Blue (CBB) R-250 organic dye from aqueous solutions, achieving a remarkable removal efficiency of 96.16 %. The morphology of the nanocomposite was characterized using SEM and FTIR, revealing particle sizes of less than 18 nm. Additionally, BET analysis was performed, indicating a high surface area that enhances adsorption capacity. The influential variables affecting dye removal, including solution pH, stirring time, adsorbent dosage, initial dye concentration, temperature and ionic strength, were optimized. The adsorption process was analysed using Langmuir, Freundlich, Temkin and Dubinin–Radushkevich isotherm models. The experimental results indicated that the process followed the Freundlich and Temkin isotherm models, suggesting the heterogeneous nature of the adsorbent surface. The kinetic conditions of adsorption were investigated using pseudo-first order and pseudo-second-order models, with results showing that the adsorption process of CBB followed the pseudo-second-order kinetic model, indicating the chemical adsorption of the dye onto the magnetic nanoparticles. The thermodynamic studies also revealed the spontaneous nature of the adsorption process, with a positive slope of the Van’t Hoff curve indicating an exothermic reaction. Due to the equilibrium time of 5 min in the adsorption mechanism, the synthesized magnetic nanocomposite demonstrated a high CBB dye removal rate, making it suitable for treating dye-containing solutions.

A computational study of the potential bioactivity of hibiscus and garcinia acids against SARS-CoV-2

2024-06-24T16:04:22+02:00

A computational chemical study was conducted on the diastereoisomers of hibiscus acid (HA) and garcinia acid (GA), investigating their docking capabilities with the main protease (6LU7) of SARS-CoV-2. Electrostatic potential mappings unveiled negative charges associated with the carboxyl and hydroxyl groups positioned at C-2 and C-3 for both hibiscus and garcinia acids. However, the presence of more negative potentials around C-2 and C-3 of hibiscus acid, compared to garcinia acid, suggests that substituents in the (2S,3R) configuration possess a stronger electron-attracting capacity than those in the (2S,3S) configuration. Molecular docking studies indicated that both hibiscus acid and garcinia acid bind to the main protease through the catalytic pocket. Nonetheless, molecular dynamics simulations revealed that only HA remained bound to the active site for 100 ns with an RMSD of less than 1 Å, whereas GA dissociated from the complex within the initial 16 ns. These findings illuminate the differential binding behaviors of the two compounds, with implications for potential therapeutic interventions against SARS-CoV-2. These findings shed light on the differential binding behaviors of the two compounds, holding implications for potential therapeutic interventions against SARS-CoV-2.

Corrosion studies, parameter effects, and surface morphology of AA5052-AA6101T6 friction stir welded joints

2024-05-13T07:27:37+02:00

Traditional fusion welding is unsuitable for welding aluminum alloys because secondary brittle phases, porosity, and cracks are likely to form as the alloy solidifies. Friction stir welding (FRSTW), a new solid-state welding method, can join similar or dissimilar aluminium (ALU) alloys. In this study friction stir welded AA5052-AA6101T6 alloy samples were tested for corrosion characteristics. The microstructure and mechanical behavior of FRSW-welded AA5052-AA6101T6 ALU alloy joints were examined relative to input parameters. Microstructure reveals that welding speed and rotation-speed affect the weld microstructure analyzed sample welded areas. Twenty-nine samples were corrosion tested in 3.5 % NaCl, household water (880 ppm – SPM), 1 M H₂SO₄, 1 M NaOH and natural seawater for 72 h. Domestic salt water and acid medium showed better resistance to corrosion than alkaline and salt media. Impedance studies demonstrated slight anodic and cathodic potential changes after friction stir welding.

Phytochemical investigation from wood residues of Dalbergia spruceana Benth

2024-08-12T20:04:45+02:00

Dalbergia spruceana Benth (Fabaceae: Papilionoideae), known in the Brazilian Amazon as ¨jacarandá-do-pará” recognized for the natural resistance of its wood has little scientific information about its secondary metabolism. In this paper, we report a phytochemical study of the wood residues of D. spruceana using classical chromatographic techniques. Thus, the chromatographic fractionation of methanolic extract resulted in the isolation of phenylpropanoid, isoflavonoids of different types (pterocarpan, isoflavonol, isoflavan, isoflavone) in addition to a neoflavonoid. A new isoflavonoid with an oxygenation pattern not previously reported was elucidated as 8,4,2'-trihydroxy-7,4'-dimethoxyisoflavonol. The structures of all the isolated compounds were determined by using 1D- and 2D-NMR techniques, mass spectrometry ESI-MS and by comparison with literature data. Most of the compounds that were identified are isoflavonoids, which are types of flavonoids that are especially recognized for their contribution to the natural resistance of the wood.

Recovery of copper from pre-concentrated printed circuit boards (PCBs) by catalyzed acidic leaching

2024-09-13T10:51:35+02:00

This study aimed to extract copper from waste printed circuit boards (WPCBs) through a sequential process involving physical pre-concentration via a shaking table, followed by acid leaching. A shredder and hammer mill were utilized to fragment the various components of the PCB into particles smaller than 1 mm. The shaking table pre-concentration tests revealed that the heavy fraction exhibited a copper grade of 56.4 % with a yield of 89.6 %. Subsequent leaching of the copper concentrate, using a solution containing 1 M H₂SO₄ and 4 vol. % H₂O₂ at 50 °C for two hours, resulted in a copper extraction efficiency exceeding 95 % with a solid ratio of 2 wt. %/V.

A simple method for identification of native collagen by reversed-polarity electrophoresis: Short report

2024-10-01T12:20:43+02:00

The high molecular weight of collagen and the high uncommon amino acid composition (proline and hydroxyproline) make the protein particular at structural and physicochemical levels compared to others. Polyacrylamide gel electrophoresis (PAGE) is a simple and inexpensive method to identify collagen integrity; however, native forms of proteins generally show low quality bands. In this work, we considered the charge of the protein to perform a very simple method to identify the native form of type I collagen, exhibiting an appropriate electrophoretic resolution. First, we determined the collagen charge at different pHs and then modified a previously published method by changing the gel buffer and reversing the polarity of the electrophoresis chamber by turning the power cords; now the protein was moved from the anode to the cathode. The result was well-resolved protein bands that maintained their classical structure without degradation after PAGE, which were confirmed by extracting the protein from the native-PAGE and electrophoresing it in a sodium dodecyl sulphate-PAGE. This advantage could be useful when the electrophoresed native collagen is used by Western blotting for recognition with antibodies.

Waste corn silk for eco-friendly silver nanoparticles: Green synthesis, characterization and determination of enzyme inhibition properties

2024-08-18T23:50:57+02:00

Due to the increasing population and consumption rate, the sustainable use of resources is very important. Corn is one of the most produced grains in the world. However, many parts of it, such as corn silk, roots and corn husk are disposed of as agricultural waste. Within the sustainability, it is possible to bring waste into the field of technology and develop new products with green synthesis. In this study, the waste corn silk was dried, extracted and used as a precursor in synthesis of silver nanoparticles (CS-AgNPs). The CS-AgNPs were characterized using ultraviolet (UV) spectrophotometry, infrared (FTIR) spectrophotometry and scanning transmission electron microscope (SEM). Moreover, the inhibition effects of CS-AgNPs on enzymes such as α-amylase, α-glycosidase, urease, acetyl cholinesterase, and xanthine oxidase which are important for the treatment of some diseases were determined. The obtained nanoparticles gave the maximum absorbance at 470 nm and the average size of the nanoparticles was found as 65 nm. It was determined that CS-AgNPs showed very good antioxidant activity and inhibitory effects on α-amylase (52.27%), α-glycosidase (43.51%), urease (80.33%), acetyl cholinesterase (66.17%), and xanthine oxidase (73.67%). The obtained results show that the nanoparticles synthesized using the green synthesis technique could be used in medicine and pharmaceuticals.

A comparative study on ecological risk assessment of some potentially toxic elements accumulation in surface sediment of stagnant and running water ecosystems in Meriç delta wetland, Turkish Thrace

2024-09-16T11:35:27+02:00

This study determined arsenic, chromium, cadmium, copper, zinc, nickel and lead concentrations in the sediment of the lake and river and evaluated their ecological risk profile and compared the ecological risk profile of some potentially toxic elements accumulated in surface sediment of stagnant and running water ecosystems in the Meriç Delta Wetland, Turkish Thrace which is located in the European part of Turkey and have two important river systems, Meriç and Ergene, which provide freshwater resources for the region. Sediment samples were taken seasonally from three stations (one station from the river and two stations from the lake) in 2020. Ecological and biological risk analyses were calculated using the potential ecological risk index (RI), biological risk index (mERM-Q_i), contamination factor (CF), contamination degree (CD) and pollution load index (PLI). As a result, although RI stated that Cd was determined as the riskiest element and mERM-Q_i stated that Zn was determined as the riskiest element, indicated that there were no high ecological risks besides the investigated elements in the area. Although it is expected that the sediment quality of running water systems is better than that of stagnant water systems, the results of risk indices in the present study showed that the station selected for running water was the riskiest station in terms of potentially toxic elements.