A new molecularly imprinted polymer (MIP)-based disposable electrochemical sensor for dipyridamole (DIP) determination was obtained. The sensor was rapidly prepared by potentiodynamic electrochemical polymerization on a pencil graphite electrode (PGE) using curcumin (CUR) as a functional monomer and DIP as a template molecule. After the optimization of the conditions (pH, monomer–template ratio, scan rate, number of cyclic voltammetric cycles applied in the electro-polymerization process and extraction time of the template molecule) for MIP formation, DIP voltammetric behavior at the modified electrode (MIP_PGE) was investigated. DIP oxidation took place in a pH-dependent, irreversible mixed diffusion-adsorption controlled process. Differential pulse voltammetry (DPV) and adsorptive stripping differential pulse voltammetry (AdSDPV) were used to quantify DIP from pharmaceutical and tap water samples. Under optimized conditions (Britton–Robinson buffer at pH = 3.29), the obtained linear ranges were 5.00 × 10−8–1.00 × 10−5 mol/L and 5.00 × 10−9–1.00 × 10−7 mol/L DIP for DPV and AdSDPV, respectively. The limits of detection of the methods were 1.47 × 10−8 mol/L for DPV and 3.96 × 10−9 mol/L DIP for AdSDPV.

Laccases are enzymes with low substrate specificity that in certain cases require the presence of a mediator in order to work properly. Therefore, this paper investigated the degradation of Orange G, Ponceau 4 R and Methyl Red in the presence of laccase isolated from Trametes versicolor and laccase-ABTS system. Laccase, in high concentration, was able to oxidize only Orange G and Ponceau 4 R, with a degree of decolorization less than 10 % in 20 min. In the presence of laccase-ABTS system, the reaction is much faster, and at least 40 % of dyes were degraded in 15 min. A kinetic model accounting for enzymatic oxidation of all dyes, including a step for enzyme operational inactivation, was proposed. This study proves that we can use a single kinetic model for the oxidation of all dyes in the laccase-ABTS system.

A new method for the determination of the antiplatelet drug dipyridamole (DIP) in pharmaceuticals using a molecularly imprinted polymer (MIP)-modified pencil graphite electrode (PGE) is proposed. The modified electrode was prepared simply and rapidly by electropolymerization of caffeic acid (CA) in the presence of DIP and subsequent DIP extraction with ethanol, resulting in a cost-effective, eco-friendly disposable modified electrode (MIP_PGE). Several working conditions (monomer and template concentration, number of voltametric cycles, scan rate extraction time, and solvent) for the MIP_PGE preparation were optimized. The differential pulse voltammetric (DPV) oxidation signal of DIP obtained at MIP_PGE was 28% higher than that recorded at bare PGE. Cyclic voltammetry emphasized DIP irreversible, pH-dependent, diffusion-controlled oxidation at MIP_PGE. Differential pulse and adsorptive stripping voltammetry at MIP_PGE in phosphate buffer solution pH = 7.00 were applied for the drug quantitative determination in the range of 1.00 × 10−7–1.00 × 10−5 and 1.00 × 10−8–5.00 × 10−7 mol/L DIP, respectively. The obtained limits of detection were at the tens nanomolar level.

In our previous research, we demonstrated that honey and its biomimetic natural deep eutectic solvent (NaDES) modulate the antioxidant activity (AOA) of the raspberry extract (RE). In this study, we evaluated the AOA behaviour of the mixture honey/NaDES-honeysuckle (Lonicera caprifolium, LFL) extract and compared it with the mixture honey/NaDES-RE. These two extracts have similar major flavonoids and hydroxycinnamic acid compounds but differ in their total content and the presence of anthocyanins in RE. Therefore, it was of interest to see if the modulation of the LFL polyphenols by honey/NaDES was similar to that of RE. We also evaluated the prebiotic activity of these mixtures and individual components on Limosilactobacillus reuteri DSM 20016. Although honey/NaDES modulated the AOA of both extracts, from synergism to antagonism, the modulation was different between the two extracts for some AOA activities. Honey/NaDES mixtures enriched with LFL and RE did not show significant differences in bacterial growth stimulation. However, at a concentration of 45 mg/mL, the honey -LFL mixture exhibited a higher effect compared to the honey-RE mixture. The antioxidant and prebiotic properties of mixtures between honey and polyphenol-rich extracts are determined by multiple interactions in complex chemical systems.

Quince fruits are used to make jams, jellies, and juices, resulting in by-products like seeds, pulp, and skin. These by-products contain bioactive compounds such as phenolic acids, flavonoids, and polysaccharides, which offer potential health benefits. Utilizing these by-products to produce fiber-enriched powders and polyphenol-enriched extracts can yield valuable nutrient-rich biomass and reduce waste. This study aimed to assess the potential of quince pomace for producing fiber-enriched powders and polyphenol-enriched extracts, for which this substance’s chemical composition, properties, and antioxidant activity were examined. Extraction with water or ethanol was employed, and the polyphenol content in the supernatant was analyzed using high-pressure liquid chromatography (HPLC).

Honey is a highly valued natural product with antioxidant, antimicrobial and anti-inflammatory properties. However, its antioxidant activity (AOA) is not as high as that of other honeybee products, such as propolis. Several polyphenol-honey formulations have been proposed up to now, most of them using maceration of biomass in honey or mixtures with liquid extracts, which either limit polyphenols bioavailability or destroy the characteristics of honey. To improve the health benefits of honey by increasing AOA and keeping its structural and sensory properties, we propose its enrichment in a polyphenol extract of raspberry after solvent evaporation. A honey-biomimetic natural deep eutectic solvent (NaDES) was prepared and compared with honey. The main polyphenols found in the raspberry extract were tested in combination with honey and NaDES, respectively. The AOA was determined by DPPH, ABTS, CUPRAC, and FRAP methods. The AOA behaviour of honey-polyphenol mixtures varied from synergism to antagonism, being influenced by the AOA method, polyphenol type, and/or mixture concentration. The honey-biomimetic NaDES resulted in similar AOA behaviour as with honey mixed with polyphenols. Honey seems to have additional properties that increase synergism or reduce antagonism in some cases. Honey and its biomimetic NaDES modulate AOA of polyphenols extract.

Fungi are known for their capacity to produce two main categories of enzymes, cellulolytic and lignolytic, both valuable for biodegradation of lignocellulosic biomass [...]

Antibiotics are antibacterial agents applied in human and veterinary medicine. They are also employed to stimulate the growth of food-producing animals. Despite their benefits, the uncontrolled use of antibiotics results in serious problems, and therefore their concentration levels in different foods as well as in environmental samples were regulated. As a consequence, there is an increasing demand for the development of sensitive and selective analytical tools for antibiotic reliable and rapid detection. These requirements are accomplished by the combination of simple, cost-effective and affordable electroanalytical methods with molecularly imprinted polymers (MIPs) with high recognition specificity, based on their "lock and key" working principle, used to modify the electrode surface, which is the "heart" of any electrochemical device. This review presents a comprehensive overview of MIP-modified carbon-based electrodes developed in recent years for antibiotic detection. The MIP preparation and electrode modification procedures, along with the performance characteristics of sensors and analytical methods, as well as the applications for the antibiotics' quantification from different matrices (pharmaceutical, biological, food and environmental samples), are discussed. The information provided by this review can inspire researchers to go deeper into the field of MIP-modified sensors and to develop efficient means for reliable antibiotic determination.

Honeysuckle (Lonicera caprifolium) is a perennial flowering plant from the genus Lonicera of the family Caprifoliaceae. Lonicera caprifolium flowers are used in herbal traditional medicine for their antibacterial, antioxidant and antiviral activities. The objective of this research was to optimize the ultrasound-assisted extraction (UAE) process of polyphenols from Lonicera caprifolium flowers using Design of Experiments (DoE) and Response Surface Methodology (RSM). We used a three-level factorial model with three variable factors (ethanol concentration, time and the ratio between solvent and plant material). The model and the data indicated that the ethanol concentration was highly significant (p<0.05), while the other two were less significant for the extraction of the maximum total phenolic compounds and the maximum antioxidant activity of the extracts. The antioxidant activity was performed by DPPH, ABTS and FRAP methods. The polyphenols were identified by HPLC. The optimal condition obtained for the extraction of polyphenols from honeysuckle by UAE will be used for bioproduct formulation in future work.

Honey is a natural product that has the characteristics of a deep eutectic natural solvent (NADES) due to the intermolecular interactions between monosaccharides and disaccharides, especially the hydrogen bonds formed between them. [...]

Diatomite, also known as diatomaceous earth (DE), is a sedimentary rock formed by the deposition of shells of unicellular microscopic algae of the class Bacillariophyceae (diatoms). [...]

This study was focused on creating a new and effective immobilization method for Trametes versicolor laccase (Lc) by using chitosan (CS) microspheres activated with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride. The activation of the support alternated with immobilization of the enzyme, in repetitive procedures, led to obtaining three different products. Also, the physicochemical properties of the new products were investigated and compared with those of free laccase. The discoloration and reusability properties of the immobilized Lc were evaluated using indigo carmine (IC) as a model micropollutant. The ESEM and FT-IR methods demonstrated that the Lc was successfully immobilized. The relative reaction rate and the total amount of immobilized Lc were tripled using the iterative protocol as proved by specific and Bradford assays. The maximum amount of immobilized Lc was 8.4 mg Lc/g CS corresponding to the third immobilization procedure. Compared to the free Lc, the operational stability of the immobilized Lc was significantly improved, presenting a maximum activity plateau over a pH range of 3-5 and a temperature range of 25-50 °C. The thermal inactivation study at 55 °C proved that the immobilized enzyme is three times more stable than the free Lc. The isoconversional and Michaelis-Menten methods showed that the immobilization did not affect the enzyme catalytic properties. After 32 days of storage, the residual activities are 85% for the immobilized laccase and 40% for the free one. In similar conditions, the free and immobilized Lc (2.12 x 10-6 M) completely decolorized IC (7.15 x 10-5 M) within 14 min. The immobilized Lc activity remained almost constant (80%) during 10 reusability cycles. All these results highlight the substantial advantages of the new immobilization protocol and demonstrate that immobilized Lc can be used as a promising micropollutant removal from real wastewater.

CO2 emissions are well-known for creating a lot of environmental issues, at a global scale. [...]

Spent mushroom substrate (SMS) is a significant source of enzymes and bioactive compounds [...]