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Herein, resorcinol formaldehyde resins/Bi2O2CO3 S-scheme heterojunctions are constructed via in situ polymerization. The composites displayed an improved separation efficiency of photo-induced carriers and the H2O2 production rate achieved 1178.08 μmol h−1 g−1, marking 47.18 times over that of Bi2O2CO3 under simulated solar illumination. [ABSTRACT FROM AUTHOR]

Using batch adsorption methods, this work examines the adsorption behavior of resorcinol onto two artificial calcium phosphate compounds, tricalcium phosphate apatite (PTCa) and octocalcium phosphate apatite (OCPa). The study is to assess these materials' adsorption capacities and investigate the impacts of important parameters like pH, temperature, starting concentration, and adsorbent dosage. When both the Freundlich and Langmuir isotherm models were used, the Langmuir model fit the data better, suggesting monolayer adsorption. PTCa and OCPa were shown to have maximal adsorption capabilities of 13.27 mg/g and 5.05 mg/g, respectively. According to kinetic studies, the adsorption process exhibits pseudo-second-order kinetics, which points to chemisorption. The adsorption is exothermic and spontaneous, driven by physical interactions including van der Waals forces and hydrogen bonds, according to thermodynamic considerations. The study comes to the conclusion that PTCa and OCPa, with their high adsorption capacities and advantageous thermodynamic and kinetic properties, are attractive materials for the elimination of resorcinol from aqueous solutions. [ABSTRACT FROM AUTHOR]

Terpenes, created in Nature via tail‐to‐head terpene (THT) cyclizations, have long fascinated chemists due to their complex structures and biological activities. Recreating such THT cyclizations in the laboratory using man‐made catalysts has been challenging. Especially difficult is performing the reaction in an enantioselective fashion, as the substrate is flexible and does not contain much functionality to form strong interactions with the chiral catalyst. This study explores the enantioselective THT cyclization inside hexameric capsules self‐assembled from optically active resorcin[4]arene derivatives. An unexpected odd‐even effect, where the enantioselectivity of the reaction depended on the length of the alkyl chain attached to the resorcin[4]arene capsule was uncovered. To our knowledge, this is the first example of an odd‐even effect in the catalyst itself, and also the first instance in which this effect is related to the enantioselectivity of the reaction. [ABSTRACT FROM AUTHOR]

In the present work, a simple supramolecular approach was used to spontaneously form nanoparticles from sodium carboxymethylcellulose and viologen calix[4]resorcinol as a result of joint self‐assembly in water at room temperature. Supramolecular interactions between them led to the formation of nanoparticles, the morphology and properties of which depend on polymer/macrocycle ratio. When there is excess of macrocycle, the nanoparticles bind lipophilic oleic acid, and when there is excess of polymer, they bind hydrophilic doxorubicin. Interestingly, the solubilization of lipophilic quercetin into these nanoparticles was significantly increased compared to the pure polymer and macrocycle, regardless of their ratio. The nanoparticles of triple composition (polymer/macrocycle/drug) have a more effective penetration ability in tumorcells than those of double composition (polymer/drug). The presented results are the first step towards the creation of new nanotechnologies to improve the bioavailability and delivery of bioactive components. [ABSTRACT FROM AUTHOR]

Various organic compounds susceptible to anodic polymerization were selected to study the effects of two solvents: acetic acid and ethyl acetate. Phenol and most of its derivatives, as well as resorcinol and 3,5-dihydroxybenzoic acid, exhibited typical electrode deactivation similar to other solvents; however, a continuous decrease in peak currents was not observed for 4-tert-butylphenols or salicylic aldehyde. Similar behavior was noted for monomers unrelated to phenols. In general, peaks were observed only for certain compounds and not in the initial voltammogram. Significant differences between the two solvents were observed in the subsequent voltammetric curves for some monomers. Microelectrode studies using 4-methoxyphenol as a model compound revealed notable differences between acetic acid and ethyl acetate in terms of curve shapes and the onset potentials of the plateaus. Plateau currents were used to estimate the solvent composition, demonstrating relatively high sensitivity to the acetic acid content. [ABSTRACT FROM AUTHOR]

Epoxy resins are often used as protective coatings because of their exceptional adhesion, mechanical strength, chemical resistance, and anticorrosive properties. However, the use of bisphenol A (BPA)‐based epoxies has been linked to environmental and health concerns. The objective of this study was to develop eco‐friendly epoxy coatings for mild steel corrosion protection using bio‐based resorcinol (RESO) and isosorbide (ISO), as well as the development of novel Zn‐Al layered double hydroxide (LDH) and Ce‐bentonite fillers. The epoxy resins were synthesized by reacting resorcinol and isosorbide or their combinations with epichlorohydrin, with sodium hydroxide as a catalyst. Zn‐Al LDH and Ce‐bentonite were produced through co‐precipitation and ion exchange techniques. Five eco‐friendly epoxy formulations were synthesized by varying the concentrations of resorcinol and isosorbide. The plain epoxy coating and composite coatings, consisting of 3, 5, or 7 wt.% LDH/clay fillers were analyzed. FTIR was used to examine the resin's epoxide groups. 100% RESO epoxy demonstrated superior adhesion, hardness, chemical resistance, water absorption, and corrosion prevention compared with other epoxy‐based coating formulations. When it comes to the mechanical properties of coatings, Zn‐Al LDH‐based coatings have better scratch hardness than Ce‐Bentonite due to their layered structure, which enables robust interfacial contact with epoxy and better stress transfer. Salt spray tests revealed that resorcinol‐based epoxy coatings with 5 wt.% filler exhibited outstanding corrosion resistance after 500 h. Therefore, this research offers bio‐based epoxies and LDH/clay composites as an environmentally friendly, high‐performance alternative to petroleum‐based BPA epoxies for anticorrosion coatings. [ABSTRACT FROM AUTHOR]

The objective of this study was to develop a type of glued laminated timber (Glulam) element from solid eucalyptus wood residues. The hybrid wood Eucalyptus urophylla × Eucalyptus grandis was used and characterized regarding its physical and mechanical properties to determine density, moisture content and dimensional stability. Glulam elements were manufactured from whole blades and residues, glued with resorcinol-formaldehyde adhesive and polyurethane. Non-destructive tests of free transverse vibration, longitudinal vibration and stress wave were conducted in Glulam elements, plus tests of compressive strength, parallel compressive strength, and shear strength in wood and glue joints under two moisture conditions (dry and saturated). Wood residues of the E. urophylla × E. grandis hybrid have good physical and mechanical properties that allow its use for the manufacture of Glulam elements. Adhesives showed high resistance when tested in dry condition but performed differently in saturated condition. The type of adhesive used did not differ in the resistance of Glulam. Glulam elements with residues showed satisfying results when compared to elements with whole blades, demonstrating that small pieces are useful for manufacture. [ABSTRACT FROM AUTHOR]

This study reveals that the synthesis of a novel heterogeneous gaur gum-supported DABCO functionalized nickel(II)catalyst and its application for the synthesis of 2-amino-3-cyano-7-hydroxy-4H-chromenes. The synthesized GG@Ni(II) catalyst was characterized by FT-IR, XRD, EDX, and SEM techniques. The catalytic activities of this synthesized heterogeneous catalyst were examined in one-pot multicomponent synthesis of chromene derivatives under ultrasonic condition. A simple, benign and highly efficient ultrasound-mediated route was designed to produce chromene derivatives via one-pot, multicomponent reaction of aldehyde, malononitrile, and resorcinol at room temperature. The ultrasound-mediated synthetic route was studied here exhibits some remarkable advantages such as short reaction times, green reaction conditions, operational simplicity, high yields, and easy work-up and purification steps. In addition to this interestingly found that there was unnoticeable loss of reactivity when the catalyst was quantitatively recovered from the reaction medium and recycled up to five times. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Real‐time on‐site monitoring of resorcinol (RS) concentrations is crucial for detecting hazardous levels, enabling prompt response measures to mitigate potential environmental and health risks. In this study, we developed an innovative method using CoNi@CN‐2 nanozymes to activate peroxymonosulfate (PMS) for oxidizing 3,3',5,5'‐tetramethylbenzidine (TMB). Our results show that the formation of Ni2+ through the oxidation of Ni0 on the CoNi@CN‐2 surface significantly enhances the electron‐donating capacity of Co0. The catalytic reaction of TMB is mediated by redox active species (SO4•−, •O2−, •OH and 1O2). RS drives colorimetry by transferring electrons to the benzene ring and specific nitrogen atoms in ox‐TMB, reducing ox‐TMB to TMB. Furthermore, the colorimetric assay shows a robust linear correlation between RS concentration and absorbance (Abs), described by Abs = –0.44[RS] + 0.886 (0—200 μmol/L, R2 = 0.983). Also, we introduce a novel smartphone‐integrated autonomous detection software that can analyze RS concentration and grayscale values (GSV), yielding GSV = 0.327[RS] + 63.601 (0—200 μmol/L, R2 = 0.990) with a detection limit of 5.29 μmol/L. Additionally, excess PMS leads to ROS attacking specific sites in ox‐TMB, forming secondary oxidation products. This study has enabled rapid and accurate detection of RS, making a significant contribution to environmental safety and protection. [ABSTRACT FROM AUTHOR]

ObjectiveTo establish an analytical method for the determination of resorcinol, ferulic acid, phenethylresorcinol and benzoyl peroxide in freckle whitening cosmetics by high performance liquid chromatography (HPLC), to provide data support for the establishment of cosmetics inspection methods and technical support for the supervision of the cosmetics industry.MethodsThe analytes in samples were extracted by ultrasonic acetonitrile after methanol vortex, and then filtered by centrifugation and microporous filter membrane. Finally, the analytes were separated with a SVEA C4 column (250 mm×4.6 mm, 5 μm). The mobile phase was composed of 0.1% phosphoric acid solution -acetonitrile, and the gradient elution was applied, with a flow rate of 1.0 mL·min-1. The samples were detected by an ultra-violet detector and quantified by external standard method.ResultsResorcinol, ferulic acid, phenylethylresorcinol and benzoyl peroxide showed good linearity in the experimental range with r>0.999. HPLC was used to investigate the positive spiked recoveries of ferulic acid or phenylethylresorcinol with different matrices. The results showed that the recoveries were all in the range of 87.48% to 101.00%, and the relative standard deviations were all in the range of 3.4% to 4.1%. Furthermore, HPLC also examined the blank matrix spiked with the recoveries ranged from 93.26% to 107.66%, with the relative standard deviation of 0.90% to 2.90%. The limits of detection ranged from 0.000 8% to 0.002%. Among the 30 batches of standard freckle whitening cosmetics determined, 6 batches of which were detected with phenethylresorcinol and 1 batch with ferulic acid.ConclusionHPLC is a method with rapidity, simplicity, and high sensitivity, which is suitable for the simultaneous determination of resorcinol, ferulic acid, phenethylresorcinol and benzoyl peroxide in commercially available cosmetics.

The extraction of uranium from nuclear wastewater through photocatalysis represents a highly viable, environmentally friendly, and sustainable approach, contributing significantly to mitigating environmental degradation while facilitating the efficient recovery of uranium resources. Nonetheless, the development of highly efficient photocatalysts with rapid charge carrier migration and surface reaction kinetics for the effective removal of U(Ⅵ) from uranium-containing wastewater remains a formidable challenge. This study successfully employed template-free self-assembly techniques to fabricate hollow tubular g-C3N4(TCN) and synthesized a tubular donor-acceptor(D-A) organic semiconductor photocatalyst, B-TCNx, by incorporating hydroquinone into the framework of TCN. This innovative photocatalyst was utilized for the photocatalytic removal of U(Ⅵ) under ambient air conditions. The construction of an intra-molecular D-A system enables the separate accumulation of electrons and holes in the acceptor and donor moieties, thereby significantly reducing electron-hole recombination. Furthermore, the spatial separation of electrons and holes in the acceptor and donor moieties leads to the formation of an intrinsic electric field, which facilitates the migration of charge carriers. The research findings indicate that B-TCN60 achieved a remarkable removal rate of 96.8% for U(Ⅵ) within 120 minutes, with a kinetic constant(0.03114 min−1) that is 2.58 times higher than that of TCN(0.01215 min−1). Moreover, negligible performance variation was observed after five consecutive cycles, demonstrating the excellent stability and reproducibility of the photocatalyst. The enhanced performance of B-TCN60 can be attributed to its unique structural and electronic properties. The hollow tubular structure of TCN provides a high surface area, which is beneficial for the adsorption of uranium ions. Additionally, the incorporation of hydroquinone into the TCN framework not only improves the light absorption properties of the photocatalyst but also plays a crucial role in the formation of the D-A system. The effective separation of charge carriers within the D-A system minimizes recombination losses and maximizes the efficiency of the photocatalytic process. The study’s findings underscore the potential of D-A organic semiconductor photocatalysts in addressing environmental challenges associated with nuclear waste, while also enhancing the recovery of valuable uranium resources. The novel approach of utilizing a D-A system in the photocatalyst design opens new avenues for the development of advanced materials with superior photocatalytic performance. The innovative use of template-free self-assembly techniques to fabricate hollow tubular g-C3N4 and the successful synthesis of the B-TCNx photocatalyst represent significant advancements in the field. The high removal efficiency, stability, and reproducibility of B-TCN60 highlight its potential for practical applications in environmental remediation. This work not only contributes to the field of environmental remediation but also offers a sustainable solution to the global issue of nuclear waste management.

Background: Electrodeposition of functional films from polyphenol-containing solutions has emerged as a new field of surface functionalization from bio-sourced molecules. There is, however, almost no knowledge about the chemical structure of such complex films. It is the aim of this research to use the known electrodeposition of films made from catechol and resorcinol, two isomers of dihydroxybenzene, to understand the electrodeposition of a more complex polyphenol, quercetin, which is constituted from a fused catechol and resorcinol moiety. The aim of this article is hence to introduce some methodology in the interpretation of the electrochemical behavior of complex polyphenols starting from their building blocks. Methods: Cyclic voltammetry (CV) is used to deposit films from quercetin and from equimolar blends of catechol and resorcinol on amorphous carbon and gold working electrodes. The main experimental parameter was the potential sweep rate used during the CVs. Results: The CV of quercetin is not the exact sum of the CV of the catechol + resorcinol blends, but the major features are conserved, namely the presence of two main oxidation peaks affiliated to those of catechol and resorcinol but shifted to less anodic potentials. In addition, the anodic electron transfer coefficients of the two oxidation waves of quercetin are higher than those measured in the catechol resorcinol blend. However, film deposition ability is reduced with quercetin compared to catechol + resorcinol blend in probable relationship to steric hindrance occurring during the non-electrochemical crosslinking of the deposit. The quercetin-based films deposited at 10 mV·s−1 on gold electrodes are conformal and display some antioxidant activity.

The continuous exploration of new analogs of calixarenes and pillararenes unlocks infinite opportunities in supramolecular chemistry and materials. In this work, we introduce a new class of macrocycle, phenyl‐extended resorcin[4]arenes (ExR4), a unique and innovative design that incorporates unsubstituted phenylene moieties into the resorcin[4]arene scaffold. Single‐crystal analysis reveals a chair‐like conformation for per‐methylated ExR4 (Me‐ExR4) and a twisted "Figure‐of‐eight" shaped conformation for per‐hydroxylated ExR4 (OH‐ExR4). Notably, OH‐ExR4 demonstrates exceptional adsorption capability toward I3− ions in an aqueous solution, with a rapid kinetic rate of 1.18×10−2 g ⋅ mg−1 ⋅ min−1. Furthermore, OH‐ExR4 shows excellent recyclability and potential as a stationary phase in column setups. The discovery of ExR4 opens up new avenues for constructing new macrocycles and inspires further research in functional adsorption materials for water pollutant removal. [ABSTRACT FROM AUTHOR]

A palladium capsule, made of three cavitands, namely P,P-dichlorido{5,17-bis[5-(diphenylphosphanyl)-4(24),6(10),12(16),18(22)-tetramethylenedioxy-2,8,14,20-tetrapentylresorcin[4]arenyl-17-oxymthyl]-4(24),6(10),12(16),18(22)-tetramethylenedioxy-2,8,14,20-tetrapentylresorcin[4]arene}palladium(II) (1), was synthetized by coordination of the corresponding diphosphinated ligand and the palladium precursor [PdCl2(PhCN)2] in 27% yield. The obtained P,P-chelate complex was fully characterized by elemental analysis, NMR and mass spectrometry. Molecular dynamics simulations carried out on the metallo-capsule showed the structure made by the three cavitands was slightly distorted over the 1 μs of the simulation. The evaluation of the palladium capsule 1 in the reaction between arylacetylenes and Et3SiH in undried conditions unequivocally demonstrates a drastic change in chemoselectivity, with the formation of the partially hydrogenation product rather than the hydrosilylation products observed with complexes whose active center is more accessible, for instance [PdCl2(PPh3)2]. [ABSTRACT FROM AUTHOR]

The presented work focused on the preparation of a voltammetric sensor for hydroquinone (HQ) determination using a polycrystalline platinum electrode modified with Alizarin Red S (ARS). The electrode was prepared by electropolymerization of ARS on a platinum electrode through the application of 100 cyclic voltammetric segments between –0.4 and 1.2 V against Ag/AgCl (quasi-reference electrode). The modified poly (ARS)-Pt electrode was characterized in terms of stability and cyclic voltammetric behavior as a sensor for HQ in aqueous media. The modified electrode showed excellent stability and higher current than the unmodified electrode for the electrooxidation of HQ. Thus, the oxidation of HQ at poly (ARS)-Pt electrode exhibits notable electrocatalytic performance. The limit of detection is 0.16 µM, and the standard curve exhibits a linear relationship over the range from 0.25 to 15 µM (R2 = 0.999). Investigation of the response to some potential interferences indicated that the electrode is unresponsive to Na+, K+, Mg2+, Ca2+, Zn2+, Mn2+, Mo2+, Co2+, Bi2+, Cd2+, Ni2+, Al3+, , , Cl–, phenol and resorcinol, but shows marginal change towards Hg2+ and Cu2+. Recovery tests indicated recovery values between 97.0% and 100.81% when analyzing real samples at the modified electrode. [ABSTRACT FROM AUTHOR]

Microwave irradiation was used to promote the cyclocondensation of certain aldehydes and resorcinol, resulting in a sustainable synthesis of calix[4]resorcinarenes. This environmentally conscious technology possesses numerous attractive characteristics, including high productivity, short reaction time, and straightforward workup protocol. The structures of all calix[4]resorcinarenes were verified using a range of physicochemical techniques, including elemental analysis, FT-IR, 1H NMR, and mass spectrometry. [ABSTRACT FROM AUTHOR]

Limited comprehension of differences between tight and loose poplar veneer surfaces affected the bonding performance of carbon fiber (CF)/poplar (P) veneer composites. This study assessed the impact of veneer contact angle variation and hydroxy-methylated resorcinol (HMR) coupling agent treatment on the bonding interface and strength of CF/P veneer composites. Four kinds of epoxy resin-based 3-ply CF/P composite were created: P surface/CF/P surface (SCS), P back/CF/P back (BCB), HMR-treated P surface/CF/HMR-treated P surface (HSCS), and HMR-treated P back/CF/HMR-treated P back (HBCB). Tight surface contact angle was bigger than loose surface angles, and the wettability of loose surface is better than that of tight surface. HMR treatment enhanced epoxy wettability on both sides of veneer, minimizing differences between both sides. After-HMR treatment of veneer, the bonding strength of HSCS group increased notably with 77% higher dry strength and 80% higher wet strength compared to SCS and the peeling rate of HSCS and HBCB was less than 5%. Meanwhile, HMR treatment on veneer effectively balanced epoxy adhesive distribution in bonding interface of CF/P veneer composites and obviously minimized the difference of bondline thickness of the CF/P composite caused by difference between the surface and back of veneer enhancing the bonding strength of the composite. [ABSTRACT FROM AUTHOR]

The hydrophobic reagent 6-hexyl-4-(2-thiazolylazo)resorcinol (HTAR) was investigated as part of a cloud-point extraction (CPE) system for the spectrophotometric determination of Zn(II). In the system, complexes with different stoichiometries, including 1:1 and 2:2 (Zn:HTAR), are formed. Their ground-state equilibrium geometries were optimized at the B3LYP/6-31G level of theory. The obtained structures were then used to calculate vertical excitation energies in order to generate theoretical UV/Vis absorption spectra. The comparison between theoretical and experimental spectra demonstrated that, under optimal conditions, a binuclear complex containing oxygen-bridging atoms is the dominant species. The absorbance was found to be linearly dependent on the concentration of Zn(II) within the range of 15.7 to 209 ng mL−1 (R2 = 0.9996). The fraction extracted (%E), logarithm of the conditional extraction constant (log Kex), and molar absorption coefficient (ε) at λmax = 553 nm were calculated to be 98.3%, 15.9, and 4.47 × 105 L mol−1 cm−1, respectively. The method developed is characterized by simplicity, convenience, profitability, sensitivity, and ecological friendliness. It has been successfully applied to the analysis of pharmaceutical and industrial samples. [ABSTRACT FROM AUTHOR]

An efficient method for the synthesis of novel phenylazo-containing moieties is described. The derivatives of 5-(4-(phenyldiazenyl)phenyl)-1,3,4-oxadiazole, substituted at position 2 of the heterocyclic scaffold with alkyl groups of different chain lengths, were prepared. The titled compounds were obtained using the appropriate 4-(5-alkyl-1,3,4-oxadiazol-2-yl)anilines, which were directed to diazotization and subsequently coupled to phenol, resorcinol, and N,N-dimethylaniline. Additionally, we report a mild and effective procedure for the preparation of 4-(5-alkyl-1,3,4-oxadiazol-2-yl)anilines via the selective reduction of the corresponding 2-alkyl-5-(4-nitrophenyl)-1,3,4-oxadiazoles using sodium borohydride-tin(II) chloride dihydrate as the reducing system. The chemical structures of the prepared compounds were confirmed by 1H- and 13C-NMR, IR, and UV-Vis spectroscopy. [ABSTRACT FROM AUTHOR]

C-tetra(4-methoxyphenyl)calix[4]resorcinarene was synthesized by hydrochloric acid-catalysed cyclocondensation of resorcinol and 4-methoxybenzaldehyde. Under these conditions, the reaction produces a conformational mixture of crown and chair structural conformers, which were separated and characterized by chromatographic and spectroscopic techniques. The antioxidant activity of both conformers was measured by using the DPPH assay, through which it was observed that the chair conformer showed greater antioxidant activity (IC50 = 47.46 ppm) than the crown conformer (IC50 = 78.46 ppm). Additionally, it was observed that the mixture of both conformers presented lower antioxidant activity than either conformer in isolation. The results found suggest that the chair conformer has efficient antioxidant activity that makes it a potential target for further research. [ABSTRACT FROM AUTHOR]

Calix[n]arenes, macrocycles constituted of 4–8 phenol moieties linked through methylene bridges, are stable molecules that can be selectively functionalised at the upper or lower rim. It has already been demonstrated that calixarene derivatives can be biologically or pharmacologically active compounds. More recently, suitably functionalised calixarenes and calixarene analogues (dihomooxacalixarenes, thiacalixarenes, calix[4]resorcinols, azacalixarenes, calixpyrroles, and pillarenes) were found to act as anticancer agents, at least in in vitro assays. We are reporting on the latest progress in this research field. [ABSTRACT FROM AUTHOR]

Inspired by the potent tyrosinase inhibitory activity of phenolic compounds with a 2-phenylbenzo[d]thiazole scaffold, we explored phenolic compounds 1–15 with 2-phenylbenzo[d]oxazole, which is isosterically related to 2-phenylbenzo[d]thiazole, as novel tyrosinase inhibitors. Among these, compounds 3, 8, and 13, featuring a resorcinol structure, exhibited significantly stronger mushroom tyrosinase inhibition than kojic acid, with compound 3 showing a nanomolar IC50 value of 0.51 μM. These results suggest that resorcinol plays an important role in tyrosinase inhibition. Kinetic studies using Lineweaver–Burk plots demonstrated the inhibition mechanisms of compounds 3, 8, and 13, while docking simulation results indicated that the resorcinol structure contributed to tyrosinase binding through hydrophobic and hydrogen bonding interactions. Additionally, these compounds effectively inhibited tyrosinase activity and melanin production in B16F10 cells and inhibited B16F10 tyrosinase activity in situ in a concentration-dependent manner. As these compounds showed no cytotoxicity to epidermal cells, melanocytes, or keratinocytes, they are appropriate for skin applications. Compounds 8 and 13 demonstrated substantially higher depigmentation effects on zebrafish larvae than kojic acid, even at 800- and 400-times lower concentrations than kojic acid, respectively. These findings suggest that 2-phenylbenzo[d]oxazole is a promising candidate for tyrosinase inhibition. [ABSTRACT FROM AUTHOR]

Tyrosinase, an enzyme involved in browning reactions in plants/crops exposed to mechanical injury, was isolated from the pulp of some different locally available bananas (M. cavendish, M. acuminata, and M. paradisiaca). Tyrosinase from the pulps was extracted, purified, immobilized, and characterized. Thereafter, the potentials of the immobilized tyrosinase in the possible production of l-3,4-dihydroxyphenylalanine (L-DOPA) in an improvised batch reactor was exploited using tyrosine and ascorbate as the substrates. L-DOPA production was monitored via thin-layer chromatography and spectrophotometry (Arnow's method). L-DOPA is a drug that is used in the treatment of Parkinson's disease. Hence, this study exploited a non-chemical route for its synthesis using the tyrosinase obtained from the banana pulps. The purified tyrosinase had an optimum pH and temperature of 6.5 and 7.0, respectively. The molecular weight of the purified tyrosinase was 45 kDa. Quercetin and resorcinol both competitively inhibited the purified tyrosinase from the three cultivars. Immobilized M. cavendish tyrosinase produced the highest concentration (0.60 mM) of L-DOPA after 8 h in an improvised batch reactor. The tyrosinase in the banana pulps serves as a cheap and readily available green route for the possible production of L-DOPA. [ABSTRACT FROM AUTHOR]

This work addresses the development of new methods for analyzing organic substances in various solutions, including liquid media from organisms and wastewater. Electrochemical methods are particularly relevant due to their high analysis throughput and the compactness of the required equipment. An original method is used to synthesize carbon composite nanomaterials based on organic iron salts and phenol-formaldehyde resin. The catalytic properties of these composites are evaluated through cyclic voltammetry. The study is conducted on solutions containing red and yellow blood salts, as well as phenol, ascorbic acid, resorcinol, and pyridoxine. The research determines the oxidation mechanisms of these solutions and identifies the synthesized composites that are most sensitive to each solution. When testing new electrode materials, the redox pair of blood salts should be considered a useful reference. [ABSTRACT FROM AUTHOR]

Background: Electrodeposition of functional films from polyphenol-containing solutions has emerged as a new field of surface functionalization from bio-sourced molecules. There is, however, almost no knowledge about the chemical structure of such complex films. It is the aim of this research to use the known electrodeposition of films made from catechol and resorcinol, two isomers of dihydroxybenzene, to understand the electrodeposition of a more complex polyphenol, quercetin, which is constituted from a fused catechol and resorcinol moiety. The aim of this article is hence to introduce some methodology in the interpretation of the electrochemical behavior of complex polyphenols starting from their building blocks. Methods: Cyclic voltammetry (CV) is used to deposit films from quercetin and from equimolar blends of catechol and resorcinol on amorphous carbon and gold working electrodes. The main experimental parameter was the potential sweep rate used during the CVs. Results: The CV of quercetin is not the exact sum of the CV of the catechol + resorcinol blends, but the major features are conserved, namely the presence of two main oxidation peaks affiliated to those of catechol and resorcinol but shifted to less anodic potentials. In addition, the anodic electron transfer coefficients of the two oxidation waves of quercetin are higher than those measured in the catechol resorcinol blend. However, film deposition ability is reduced with quercetin compared to catechol + resorcinol blend in probable relationship to steric hindrance occurring during the non-electrochemical crosslinking of the deposit. The quercetin-based films deposited at 10 mV·s−1 on gold electrodes are conformal and display some antioxidant activity. [ABSTRACT FROM AUTHOR]

Eucalyptus-based glued laminated timber (glulam) was produced to determine the feasibility of a non-destructive method (drilling resistance) to predict the properties of structural elements and add value to lower-quality hardwood species. Glulam was manufactured with formaldehyde (Resorcinol), reference condition, and bio-based (Castor oil-based) adhesives in two assembly schemes, the core composed either of two continuous lamellae each 105 cm long, or of two formed by the juxtaposition of shorter boards (35 and 55 cm). The shear strength of the glue line (fv0), modulus of elasticity (Ec90), and strength (fc90) in compression perpendicular to the grain; delamination (DL); and main and extended glue line thicknesses were evaluated. The Resistograph equipment was used to perform the perforation perpendicular to the glue line (samples extracted from the glulam elements) to correlate the properties. The results of this research demonstrate that the scheme of the boards had little effect on the physical and mechanical properties evaluated (except the main glue line and delamination), and the drilling resistance (DR) presents a significant correlation with practically all properties evaluated (variations in density values and other properties are explained by variations in DR values), making it possible to estimate Ec90 and fc90 with desired precision (R2adj ≈ 80%). This highlights the feasibility of using this methodology in the quality control of glulam elements. It is concluded that regardless of the adhesive, elements comprising a 105 cm-length core and external lamellae (T1 and control) are indicated for external use, presenting low delamination. Short-length central lamellae adhesively glued with PUR (T2) are not recommended for external applications due to their susceptibility to delamination. However, T2 is indicated for internal environments due to its low production cost. This study also proved the efficiency of using models based on drilling resistance to estimate wood density and its resistance to compression perpendicular to the fiber. [ABSTRACT FROM AUTHOR]

Herein, we firstly utilized H2@C60 to monitor the supramolecular interaction between a pH-driven resorcin[4]arene molecular tweezer and C60 with a notable 1H NMR chemical shift change (ca. 0.34 ppm). This work provides a new strategy for detecting weak or complex supramolecular interactions. [ABSTRACT FROM AUTHOR]

Herein, we firstly utilized H2@C60 to monitor the supramolecular interaction between a pH-driven resorcin[4]arene molecular tweezer and C60 with a notable 1H NMR chemical shift change (ca. 0.34 ppm). This work provides a new strategy for detecting weak or complex supramolecular interactions. [ABSTRACT FROM AUTHOR]

The interaction of active substances with molecular structures in stratum corneum (SC) is crucial for the efficacy and safety of cosmetic formulations and topical drugs. However, the molecular architecture of SC is highly complex and methods to unambiguously localize exogenous molecules within SC are lacking. Consequently, little is known about the distribution of actives within SC, and proposed penetration mechanisms through SC are typically limited to simple diffusion via a tortuous (lipid only) or transverse (across corneocytes and lipid matrix) pathway. In this work, 3D mass spectrometry imaging is used to determine the spatial distributions of four active substances at subcellular resolution in SC, including partitioning between the corneocytes and the intercellular lipid matrix. The results indicate that caffeine, 2-methyl resorcinol and oxybenzone are homogeneously distributed in the corneocytes but largely absent in the lipid matrix, despite considerable differences in lipophilicity. In contrast, the distribution- of jasmonic acid derivative is more inhomogeneous and indicates considerable localization to both the lipid phase and the corneocytes. [ABSTRACT FROM AUTHOR]

In this work, a series of nickel-containing samples of carbon xerogels (Ni@CX) were synthesized by introducing nickel acetate into a solution of precursors (resorcinol and formaldehyde), joint polycondensation, and subsequent pyrolysis in an atmosphere of argon. The samples were tested in the selective hydrogenation reaction of 1,3-butadiene. It was shown that catalysts prepared without the addition of complexing agents contained nickel nanoparticles (4–7 nm) stabilized in a carbon matrix. The Ni@CX catalyst made it possible to achieve a selectivity of 93% for butenes at a conversion of 94% and a temperature of 200°C, while the selectivity for the formation of butenes in the presence of an impregnated reference sample was lower than 1%, although it provided a conversion of 100% already at 75°C. It was supposed that the selectivity of catalysts prepared by the joint synthesis increased due to the blockage of nonselective catalytic sites by carbon of the support. [ABSTRACT FROM AUTHOR]

The important role to neuron communication and brain functions makes the selective and accurate detection of dopamine (DA, a typical neurotransmitter) significant. In this study, a morin‐based probe has been reported for the ratiometric DA detection. The mechanism study discloses that the inside resorcinol motif can specifically react with DA and form fluorescent azamonardine‐like product. In addition, the intrinsic emission from the internal chromophore endows ratiometric variation. With these features, selective DA sensing is realized using morin probe with a limit of detection of 2.2 nM (S/N = 3). Moreover, the practical application of the proposed method is further validated by the accurate DA determination in urine samples. This work demonstrates the possible exploration of novel small molecule‐based ratiometric‐sensing systems toward various analytes with the combination of proper reaction motif and chromophore. It is expected that the development of versatile probes for the ratiometric and accurate recognition of environmental and biological markers can refer such a design strategy. [ABSTRACT FROM AUTHOR]

Surface modification of nanocellulose to improve its compatibility with the polymer matrix is gaining considerable attention these days. Herein, nanocellulose whiskers (NCW) extracted from Acacia caesia were modified with resorcinol and hexamethylenetetramine (RH) by the refluxing method. The characteristic properties of RH-modified NCW were studied using field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), X-ray powder diffraction (XRD), thermogravimetric analysis (TGA) and UV–visible diffuse reflectance spectroscopy (UV-DRS). A marginal decrease in crystallinity index was observed by surface modification, whereas the thermal stability (Tmax) of the NCW increases by 32 °C on surface modification. The potential of modified filler in improving the properties of natural rubber latex (NR) was studied by comparing its mechanical, thermal, diffusion, permeability and biodegradability properties with neat NR and NR-NCW composites. Upon 2 phr filler loading, the tensile and tear strengths of modified NCW composites increased by 26 and 38% accordingly compared to the NR-neat. The better filler matrix interaction resulted in the marginal positive shift in the glass transition temperature, transport properties and Tmax of the modified composite. The incorporation of NCW also enhanced biodegradability and reduced the permeability of the prepared composites. [ABSTRACT FROM AUTHOR]

Aim: The aim of this study is to Quantify sialic acid for oral cancer diagnosis using different method using densitometric analysis. Background: Early detection of OSCC is critical for improving survival rates and reducing morbidity, which has prompted researchers to look for potential biomarkers to aid in early diagnosis. Saliva is an excellent diagnostic tool due to its noninvasive nature. Sialic acid levels in saliva have been found to be higher in cancer patients. Hypersialylation is associated with poor prognosis and accelerated cancer progression, as well as immune escape, tumor growth and spread, angiogenesis, and resistance to apoptosis and treatment. This study addresses the imperative need for adaptive, effective, and non-invasive strategies in the diagnosis and treatment of oral cancer, emphasising the importance of early detection for improved prognosis. This study introduces various methods for quantify levels of sialic acid in saliva, including resorcinol and orcinol assays, using colorimetric and densitometric assays. Material and Method: In this study, sialic acid detection methods have been standardized using standards as well as spent media from cancer cell lines to develop noninvasive diagnostic tools for early detection. Two methods used for the detection of sialic acid Resorcinal and Orcinol method by densitometric analysis using Image J software. Results: The study has successfully quantified sialic acid from spent media and saliva using resorcinol and orcinol method by densitometric analysis. Conclusion: In this study we aim to develop a reliable and cost-effective method for quantification of sialic acid using Image j software. The approach presents a non-invasive and efficient alternative for early cancer diagnosis showcasing its potential impact on advancing diagnostic technologies.

Self‐folding cavitands represent the quintessential form of bioinspired synthetic receptors, featuring deep hydrophobic cavities that engage in host‐guest chemistry reminiscent of that operating in biomolecules. Although remarkable proof‐of‐concept applications have been reported, the narrow and rigid spaces of the legacy resorcin[4]arene derived hosts constitute a liability towards the development of specific applications in catalysis, sensing or sequestration. While notable efforts to expand the size of the cavities have been reported, the development of confined spaces reproducing the highly adaptable nature of biological receptors is a largely unaddressed issue. This review summarizes the development of a new family of calix[5]arene derived self‐folding cavitands displaying enhanced induced fit and conformational selection phenomena. Our approach capitalizes on hydrogen bonding preorganization rather than the covalent restriction approaches customary of conventional supramolecular chemistry. [ABSTRACT FROM AUTHOR]

This article presents cyclic voltammetry, Tafel polarization, and ac. impedance spectroscopy examinations of resorcinol (RC) ion reactivity on Pt(511) single-crystal plane and the effect of surface-electrosorbed RC ions on the kinetics of UPD H (underpotentially deposited hydrogen) and HER (hydrogen evolution reaction) processes in 0.1 M NaOH solution. Obtained data delivered a proof for the RC ion surface adsorption and its later electroreduction over the potential range characteristic for the UPD H. A favourable role of platinum-adsorbed resorcinol anions on the kinetics of the UPD H and HER processes is also discussed. The above was explained via the recorded capacitance and charge-transfer resistance parameters (the presence of resorcinol at 1.5 × 10-3 M in 0.1 M NaOH caused significant reduction in the resistance parameter values by 3.9 and 2.6 times, correspondingly, for the UPD of H at 50 mV and the HER process, examined at-50 mV vs. RHE) along with the charge transients, produced by injecting small amounts of RC-based 0.1 M NaOH solution to initially RC-free base electrolyte on the Pt(511) electrode plane (a large cathodic charge-transient density of -90 µC cm-2 was recorded at the electrode potential of 50 mV). [ABSTRACT FROM AUTHOR]

Background: Q‐switched (QS) Nd: YAG laser is one of the treatment options for solar lentigines (SLs). However, the incidence of post‐inflammatory hyperpigmentation (PIH) is a common complication, especially in dark‐complexioned skin. Isobutylamido thiazolyl resorcinol (ITR) has been reported as a preventive modality for ultraviolet B (UVB)‐induced hyperpigmentation. Aims: This study aims to evaluate the efficacy and safety of ITR for the prevention of laser‐induced PIH. Patients/Methods: A randomized, evaluator‐blinded study including 24 subjects with SLs was conducted. Three SLs of each patient were randomized into three groups, which were to apply ITR twice daily, once daily, and no application for 2 weeks. Thereafter, 532‐nm QS Nd: YAG laser was performed. Incidence of laser‐induced PIH, relative melanin index (RMI), mean luminance score (L*), hyperpigmentation score, and adverse events were recorded for 2 months post‐laser. Results: The incidence of PIH at the 4th week after laser treatment was significantly lower in the ITR twice‐daily group compared to the no‐application group (20.83% vs. 50%, p = 0.028). There was no statistically significant difference in RMI, mean L*, and hyperpigmentation score between treatments at all visits. No serious adverse events were reported regarding ITR application and laser treatment. Conclusion: Two‐week application of ITR prior to QS: Nd YAG laser treatment may potentially reduce the incidence of PIH. A longer duration of application, including after the laser procedure, may be more beneficial for the prevention of laser‐induced PIH. [ABSTRACT FROM AUTHOR]

This study offers a simple voltammetric method for quantifying hydroquinone using a poly(valine)-modified carbon paste electrode (PVLMCPE). Differential pulse voltammetry, cyclic voltammetry, electrochemical impedance spectroscopy, and scanning electron microscopy were utilized to assess the performance of the developed sensor. The oxidation peak current of hydroquinone at the PVLMCPE surface significantly increased in contrast to the bare carbon paste electrode, and overpotentials decreased. Using response surface methodology, a methodical investigation of the electrochemical response of hydroquinone electro-oxidation was carried out, taking potential, pH, polymerization cycle, and scan rate into consideration as important variables. At pH 6.5, phosphate buffer solution produced the best results. In perfect circumstances, the linear detection range showed a high correlation coefficient of 0.920, ranging from 20 to 150 μM. The results showed that the limit of detection and limit of quantification were 0.092 μM and 0.027 μM, respectively. A successful assessment of the results with those obtained using the official method was necessary for validation. Additionally, the created sensor demonstrated a remarkable sensitivity in detecting hydroquinone even in the presence of common interference molecules such as resorcinol. The modified electrode exhibits notable recovery rates and can be used for accurate determination of hydroquinone in real samples due to its broad linear range, high sensitivity, and excellent reproducibility. [ABSTRACT FROM AUTHOR]

The exponential growth of the aged population worldwide is followed by an increase in the prevalence of age-related disorders. Oxidative stress plays central role in damage accumulation during ageing and cell senescence. Thus, a major target of today's anti-ageing research has been focused on antioxidants counteracting senescence. In the current work, six novel 5,7,8-trimethyl-1,4-benzoxazine/catechol or resorcinol hybrids were synthesized connected through a methoxymethyl-1,2,3-triazolyl or a 1,2,3-triazoly linker. The compounds were evaluated for their antioxidant capacity in a cell-free system and for their ability to reduce intracellular ROS levels in human skin fibroblasts, both young (early-passage) and senescent. The most efficient compounds were further tested in these cells for their ability to induce the expression of the gene heme oxygenase-1 (ho-1), known to regulate redox homeostasis, and cellular glutathione (GSH) levels. Overall, the two catechol derivatives were found to be more potent than the resorcinol analogues. Furthermore, these two derivatives were shown to act coordinately as radical scavengers, ROS inhibitors, ho-1 gene expression inducers, and GSH enhancers. Interestingly, one of the two catechol derivatives was also found to enhance human skin fibroblast viability. The properties of the synthesized compounds support their potential use in cosmetic applications, especially in products targeting skin ageing. [ABSTRACT FROM AUTHOR]

The present work aimed to create and evaluate some topical pharmaceutical forms with a role in the improvement and treatment of acne. Also, the work aims to characterize the pharmaceutical forms obtained from the point of view of efficiency by determining some physico-chemical and pharmaceutical parameters. The purpose of these determinations is to specify some important aspects with a role in prevention and avoiding recidivism. We created two different pharmaceutical forms, using two concentrations of antibiotic and keratolytic agent, namely, a solution with erythromycin 4% and resorcinol 1% and two creams with erythromycin 1.2% and resorcinol 2% in different emulsion U type ointment bases /A and A/U used in the treatment of acne depending on its stage. Our study followed the macroscopic evaluation of the pharmaceutical forms made, the ph over a period of 30 days, the influence of the ointment bases on the rheological behavior, the satisfaction of the complexity of the treatment on different forms of acne. Microbial contamination is also a quality parameter and was evaluated to observe the behavior of excipients as possible microbial culture media. [ABSTRACT FROM AUTHOR]

Cigarette butts (CBs) are small residues with mixed composition. Produced in large amounts, their accumulation in the environment has become alarming. It is possible to classify more than 7000 chemical components generated either in the burning process or when distilled from the tobacco. The aim of this work was to describe the rate of release of phenolic compounds from CBs, to determine the content of these compounds in freshly smoked CBs and to monitor the release of phenols from CBs into fresh natural waters. The kinetics of release of selected phenolic compounds (hydroquinone, resorcinol, pyrocatechol, phenol, guaiacol, o-cresol, m-cresol, p-cresol) into water was monitored for 48 h. More than 90% of the content was extracted within 10 h for all analytes. The phenolic content was determined in the CBs of five different brands. The total content of phenols determined for each sample of freshly smoked CB was 215–861 µg/CB. For all CBs analysed, phenol, pyrocatechol and hydroquinone were the most abundant analytes, accounting for up to 75% of the content of all phenols determined. Phenol was the most abundant analyte (64.6–267.8 µg/CB) in all analysed samples. The content of pyrocatechol, the second most abundant analyte, was 45.6–221.2 µg/CB and the third most abundant analyte was hydroquinone (41.71–157.5 µg/CB). Monitoring the release of phenols from CBs into fresh natural waters (river, stream, pond) under steady and slight moving conditions showed that the kinetics of release is not influenced by the type of water. On the contrary, the process of decomposition of the released compounds is influenced by the type of water. The maximum concentrations of individual phenols in CBs extracts were comparable to those determined via laboratory extraction, thus indicating that within 72 h, most of the phenolic compounds are released from CBs into natural water. This research provides missing information on the phenolic content in CBs and the rate of release into water. It thus complements previously published information on CBs as a source of environmental contamination. [ABSTRACT FROM AUTHOR]

In recent years, research on mushrooms belonging to the Hericium genus has attracted considerable attention due to their unique appearance and well-known medicinal properties. These mushrooms are abundant in bioactive chemicals like polysaccharides, hericenones, erinacines, hericerins, resorcinols, steroids, mono- and diterpenes, and corallocins, alongside essential nutrients. These compounds demonstrate beneficial bioactivities which are related to various physiological systems of the body, including the digestive, immune, and nervous systems. Extensive research has been conducted on the isolation and identification of numerous bioactive chemicals, and both in vitro and in vivo studies have confirmed their antimicrobial, antioxidant, immunomodulatory, antidiabetic, anticholesterolemic, anticancer, and neuroprotective properties. Therefore, this review aims to provide a comprehensive summary of the latest scientific literature on the chemical composition and secondary metabolites profile of Hericium spp. through an introduction to their chemical characteristics, speculated biosynthesis pathways for key chemical families, potential toxicological aspects, and a detailed description of the recent updates regarding the bioactivity of these metabolites. [ABSTRACT FROM AUTHOR]

This article primarily presents cyclic voltammetry, Tafel polarization and ac. impedance spectroscopy electrochemical examinations of resorcinol (RC) electro-reactivity on the Pt(111) surface and its influence on the kinetics of UPD H (underpotentially deposited hydrogen) and the HER (hydrogen evolution reaction) in a 0.1 M NaOH supporting solution. The collected data provided evidence of the RC-ion's surface adsorption and its further electroreduction in the presence of surface-adsorbed H radicals along with their primary beneficial role on the kinetics of the UPD H process. The above was elucidated through an evaluation of the associated charge-transfer resistance and capacitance parameters, and was carried out on the platinum (111) electrode plane, comparatively, for the RC-free and resorcinol-modified NaOH electrolyte. In addition, the recorded cathodic charge transients (obtained by injecting small amounts of RC-based 0.1 M NaOH solution to initially resorcinol-free electrolyte, carried out at the constant electrode potential characteristic to the UPD H potential zone) provided evidence that the RC species undergoes electrocatalytic reduction through the involvement of the Pt(111)-chemisorbed hydrogen radicals. [ABSTRACT FROM AUTHOR]

An affordable and highly efficient graphite‐coated electrode was developed and applied in this work as a compelling alternative to other modified electrodes in catechol determination. Electrode modification involved a simple deposition process using a commercial graphite dispersion, Aquadag®Acheson. Morphological and electrochemical studies revealed the formation of a uniform layer with enhanced surface area and significant conductivity. Catechol quantification was successfully achieved in the linear concentration range extended up to 80 μmol L−1 with a detection limit of 0.5 μmol L−1 under optimized conditions (pH 7 and an accumulation time of 2 min). Spike‐and‐recovery experiments validated the accuracy of the determination. Unlike hydroquinone, structurally similar compounds such as phenol and resorcinol did not interfere with catechol analysis. The interference posed by hydroquinone was addressed by derivative treatment of the voltammograms allowing peaks resolution. [ABSTRACT FROM AUTHOR]