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Ginger, which is the rhizome of Zingiber officinale Roscoe, is widely distributed and consumed. The taste and aroma of ginger differ depending on its geographical origin. To distinguish the origin of ginger, ginger extracts from Korea, Peru, and China were analyzed using ultra-performance liquid chromatography (UPLC) coupled to quadrupole time-of-flight mass spectrometry and nuclear magnetic resonance spectroscopy for metabolomics. Korean ginger contained more 10-gingerol, and Peruvian ginger contained more 6-gingerol and 8-gingerol. Several amino acids negatively correlated with gingerols, suggesting that amino acids are related to the biosynthesis of gingerols. Sugars, which are the main energy source, positively correlated with gingerols. Organic acids and gingerols were also positively correlated, indicating that both organic acids and gingerols are used for adaptation to the environment surrounding the root. We confirmed the features of the primary and secondary metabolites by verifying the correlation between metabolites and differences in metabolites according to ginger origin. We additionally optimized a simultaneous UPLC analytical method of marker compounds for the simple and rapid quality control of ginger. This method exhibits excellent linearity, sensitivity, and reproducibility. Using metabolomics, differences in origin were observed, and a low-end equipment analysis method for quality control can be used in the ginger industry., (© 2024 The Author(s). Journal of Food Science published by Wiley Periodicals LLC on behalf of Institute of Food Technologists.)

As primary polyphenol oxidant products, the occurrence of o-quinone is greatly responsible for quality deterioration in wine, including browning and aroma loss. The high reactivity of o-quinone causes huge difficulty in its determination. Herein, a derivative strategy combined with UHPLC-MS/MS analysis was established with chlorogenic acid quinone (CQAQ) and 4-methylcatechol quinone (4MCQ) as model compounds. Method validation demonstrated its efficiency for two analytes (R 2  > 0.99, accuracy 98.71-106.39 %, RSD of precision 0.46-6.11 %, recovery 85.83-99.37 %). This approach was successfully applied to detect CQAQ and 4MCQ, suggesting its applicability in food analysis. CQAQ in coffee was much more than 4MCQ and with the deepening of baking degree, CQAQ decreased and 4MCQ increased. The amounts of CQAQ in various vegetables were markedly different, seemingly consistent with their respective browning degrees in practical production. This study developed an accurate and robust analytical approach for o-quinones, providing technical support for their further investigation in foods., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Effect of puffing on conversion of gingerols to shogaols, physicochemical properties as well as antioxidant and anti-inflammatory activities of puffed ginger was investigated. Puffing significantly increased extraction yield and the highest value was 12.52% at 980 kPa. The significant decrease in gingerols and increase in shogaols were occurred after puffing, respectively. Especially, 6-shogaol was dramatically increased from 4.84 to 99.10 mg/g dried ginger. Puffed ginger exhibited the higher antioxidant activities (analyzed by DPPH, ABTS, TPC, and TFC) than those of control, and they were significantly increased with increasing puffing pressure. In case of anti-inflammatory activity, puffed ginger did not inhibit NO production, but significantly inhibited TNF-α and IL-6 productions. Among gingerols and shogaols, 6-shogaol showed significantly strong correlations with both antioxidant and anti-inflammatory activities. Consequently, puffed ginger can be applied to functional food industry, which dramatically increased the contents of 6, 8, 10-shogaols, the main bioactive compounds in ginger., Competing Interests: Declaration of competing interest The authors have declared no conflict of interest., (Copyright © 2023. Published by Elsevier Ltd.)

Effectively detecting catechol (CC) and hydroquinone (HQ) simultaneously is crucial for environmental protection and human health monitoring. In the study presented herein, a novel electrochemical sensor for the sensitive simultaneous detection of CC and HQ was constructed based on an electrochemically reduced graphene oxide (ERGO)-modified multi-walled carbon nanotube paste electrode (MWCNTPE). Scanning electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy and electrochemical techniques were utilized to characterize the sensing interface and investigate the sensing mechanism. Under the optimal detection conditions, the oxidation peak currents of CC and HQ show a good linear relationship with their concentrations in the range of 0.4-400 μM with a detection limit of 0.083 μM for CC and 0.028 μM for HQ (S/N = 3). Moreover, the sensor exhibits good performance and can be applied successfully in the simultaneous detection of CC and HQ in tap water samples and urine samples with satisfactory results, indicating its promising application prospects.

Recently a laccase-based biosensors with unprecedented reuse and storage capabilities in the detection of catechol compound has been manufactured using ambient Electrospray Deposition (ESD) technique. These biosensors showed to be reused up to 63 measurements on the same electrode just prepared at room temperature and pressure. In this new work the reasons behind such a high-performance functioning have been investigated by analysing the commercial sample of laccase with different chemical physics methods: Electrophoresis, Fourier Transform Infrared Spectroscopy, X-ray Fluorescence and Nuclear Magnetic Resonance Spectroscopy. The analyses reveal the presence of the starch in the sample and its essential role as stabilizing agent. Indeed, comparing the performance of starch/laccase-based biosensors with starch-free/laccase-based biosensors, both produced via ESD, showed that the starch-free biosensors lost about 40% of their performance after just the first wash. This suggests that the presence of starch in the laccase sample is a key factor in providing the high wash and storage resistance, which are essential for the fabrication of such devices., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Danggui-Jianzhong decoction (DGJZ) is a famous classical traditional Chinese medicine formula, which ingredients are complex and the quality is difficult to control. Our study aimed to identify the overall chemical profile of DGJZ qualitatively by ultra-high performance liquid chromatography with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) and UPLC. A total of 77 components, including terpenoids, flavonoids, phenolic acids, gingerols and other components, were firstly detected and characterized by UPLC-Q-TOF-MS and 18 peaks marked after analyzing the UPLC fingerprint. Finally, paeoniflorin, liquiritin, ferulic acid, cinnamic acid, glycyrrhizic acid and 6-gingerol were quantified, which was validated in terms of linearity, precision, accuracy, repeatability and recovery. Taken together, the chemical constitutes of DGJZ were systematically identified and a reliable quantitative method coupled with fingerprint analysis was successfully employed for evaluating the holistic quality, which will provide a robust foundation for the quality control of DGJZ., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Zhenwu Decoction (ZWD), a classic formula from Zhang Zhongjing's "Treatise on Typhoid Fever" in the Han Dynasty, consists of five traditional Chinese medicines: Aconiti Lateralis Radix Praeparata (ALRP), Paeoniae Radix Alba, Poria Cocos, Ginger, and Rhizoma Atractylodis Macrocephalae. To evaluate the chemical constituent consistency of ZWD before and after compatibility, an ultra-performance liquid chromatography-electrospray ionization-quadrupole time-of-flight mass spectrometry was established to comprehensively study the constituents of ZWD. By normalizing the peak area, the pairwise compatibility of ALRP and the other four medicinal herbs, as well as the compatibility of the entire formula were studied, respectively. Multivariate statistical analysis was used to identify the differences. The processed data were analyzed by principal component analysis and supervised orthogonal partial least squared discriminant analysis, and an S-plot was generated to compare the differences in the chemical composition of the two types of decoction samples. The results showed that during the decoction process of ZWD, a total of seven components were recognized as differential compounds before and after compatibility of ZWD, namely 6-gingerol, zingerone, benzoylhypaconine, hypaconitine, benzoylaconine, paeoniflorin and fuziline. The results of this study provide basic data reference for understanding the law of ZWD compatibility and are valuable for the compatibility study of other herbal medicines., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Ginger has traditionally been used to treat and prevent nausea and vomiting; however, the results of clinical trials are ambiguous. The efficacy of ginger is attributed to gingerols and their metabolites, shogaols. Since these compounds have different pharmacological profiles, the clinical efficacy of ginger products is largely dependent on their chemical composition. The goal of our study was to examine the stability of ginger, determining the 6-gingerol contents in order to assess the effects of different storage conditions. We have performed a 6-month stability test with dry ginger rhizome samples stored in a constant climate chamber in three different storage containers (uncovered glass container, glass container sealed with rubber stopper, and plastic container). The 6-gingerol contents were measured by HPLC method. The concentration of 6-gingerol decreased in all samples. In the sealed glass container, the decrease in 6-gingerol content was significantly lower than in the unsealed glass container and in the plastic container. These results demonstrate that storage conditions have a significant impact on the quality of ginger, which may also affect efficacy., Competing Interests: The authors declare no conflicts of interest., (Thieme. All rights reserved.)

Because of their unique physical, chemical, and biological characteristics, conductive nanomaterials have a lot of potential for applications in materials science, energy storage, environmental science, biomedicine, sensors/biosensors, and other fields. Recent breakthroughs in the manufacture of carbon materials, conductive polymers, metals, and metal oxide nanoparticles based electrochemical sensors and biosensors for applications in environmental monitoring by detection of catechol (CC) and hydroquinone (HQ) are presented in this review. To achieve this goal, we first introduced recent works that discuss the effects of phenolic compounds and the need for accurate, inexpensive, and quick monitoring, and then we focused on the use of the most important applications of nanomaterials, such as carbon-based materials, metals, and metal oxides nanoparticles, and conductive polymers, to develop sensors to monitor catechol and hydroquinone. Finally, we identified challenges and limits in the field of sensors and biosensors, as well as possibilities and recommendations for developing the field for better future applications. Meanwhile, electrochemical sensors and biosensors for catechol and hydroquinone measurement and monitoring were highlighted and discussed particularly. This review, we feel, will aid in the promotion of nanomaterials for the development of innovative electrical sensors and nanodevices for environmental monitoring.

Diabetic ketoacidosis (DKA), a severe complication of type 1 diabetes (T1D), is triggered by production of large quantities of ketone bodies, requiring patients with T1D to constantly monitor their ketone levels. Here, a skin-compatible hydrogel microneedle (HMN)-continuous ketone monitoring (HMN-CKM) device is reported. The sensing mechanism relies on the catechol-quinone chemistry inherent to the dopamine (DA) molecules that are covalently linked to the polymer structure of the HMN patch. The DA serves the dual-purpose of acting as a redox mediator for measuring the byproduct of oxidation of 3-beta-hydroxybutyrate (β-HB), the primary ketone bodies; while, also facilitating the formation of a crosslinked HMN patch. A universal approach involving pre-oxidation and detection of the generated catechol compounds is introduced to correlate the sensor response to the β-HB concentrations. It is further shown that real-time tracking of a decrease in ketone levels of T1D rat model is possible using the HMN-CKM device, in conjunction with a data-driven machine learning model that considers potential time delays., (© 2024 The Author(s). Advanced Materials published by Wiley‐VCH GmbH.)

Constructing relatively inexpensive nanomaterials to simulate the catalytic performance of laccase is of great significance in recent years. Although research on improving laccase-like activity by regulating ligands of copper (amino acids or small organic molecules, etc.) have achieved remarkable success. There are few reports on improving laccase-like activity by adjusting the composition of metal Cu. Here, we used perovskite hydroxide AB(OH) 6 as a model to evaluate the relationship between Cu based alloys and their laccase-like activity. We found that when the Cu/Mn alloy ratio of the perovskite hydroxide A point is greater than 1, the laccase-like activity of the binary alloy perovskite hydroxide is higher than that of the corresponding single Cu. Based on the measurements of XPS and ICP-MS, we deduced that the improvements of laccase-like activity mainly attribute to the ratio of Cu + /Cu 2+ and the content of Cu. Moreover, two types of substrates (toxic pollutants and catechol neurotransmitters) were used to successfully demonstrated such nanozymes' excellent environmental protecting function and biosensing property. This work will provide a novel approach for the construction and application of laccase-like nanozymes in the future., Competing Interests: Declaration of competing interest The authors declare that they have no conflict of interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: Catechol (CC), a prevalent phenolic compound, is a byproduct in various agricultural, chemical, and industrial processes. CC detection is crucial for safeguarding water quality and plays a pivotal role in enhancing the overall quality of life of individuals. Electrochemical biosensors exhibit rapid responses, have small sizes, and can be used for real-time monitoring. Therefore, the development of a fast and sensitive electrochemical biosensor for CC detection is crucial., Result: In this study, a laccase-based electrochemical biosensor for detection of CC is successfully developed using Fe 3 O 4 nanoparticles as medium and optimized by applying a magnetic field. This research proposes a unique strategy for biosensor enhancement by actively controlling the distribution of magnetic materials on the electrode surface through the application of a magnetic field, resulting in a visibly alternating stripe pattern. This approach effectively disperses magnetic particles, preventing their aggregation and reducing the boundary layer thickness, enhancing the electrochemical response of the biosensor. After fabrication condition optimization, CC is successfully detected using this biosensor. The fabricated sensor exhibits excellent performance with a wide linear detection range of 10-1000 μM, a low detection limit of 1.25 μM, and a sensitivity of 7.9 μA/mM. The fabricated sensor exhibits good selectivity and reliable detection in real water samples. In addition, the laccase-based sensor has the potential for the fast and accurate monitoring of CC in olive oil., Significance: The magnetic field optimization in this study significantly improved the performance of the electrochemical biosensor for detecting CC in environmental samples. Overall, the sensor developed in this study has the potential for fast and accurate monitoring of CC in environmental samples, highlighting the potential importance of a magnetic field environment in improving the performance of catechol electrochemical biosensors., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: Dietary supplements derived from botanicals are commonly consumed and investigated in biomedical studies for their potential health benefits. Accurate identification and quantification of key chemical constituents from botanical ingredients is necessary for consistent product preparations and reproducible research results. Manufacturers need quantitative reference materials of the chemical constituents of interest to verify the content of ingredients and products. The rigor and reproducibility of biomedical research is enhanced through thorough characterization of the interventions used in mechanistic, clinical, and safety investigations. Quantitative reference materials enable reliable product quality assessments and reproducible research results., Objective: Solution-based certified reference material (CRM) mixes were developed as calibrants for phytochemicals in ginger and kava. The kava CRM contained yangonin, desmethoxyyangonin, dihydrokavain, DL-kavain, methysticin, dihydromethysticin, flavokawain A, flavokawain B, and flavokawain C. The ginger CRM contained 6-gingerol, 8-gingerol, 10-gingerol, 6-shogaol, 8-shogaol, and 10-shogaol., Methods: Each phytochemical was sourced as an isolated compound and assigned a purity factor by a mass balance approach accounting for residual impurities. The solution standard mixes were formulated by gravimetric addition of each phytochemical incorporating the purity factor and diluting with acetonitrile to the target concentrations of 500 µg/mL for the gingerols and shogaols, 250 µg/mL for the kavalactones, and 25 µg/mL for the flavokawains., Results: The concentration accuracy of each component in the solution mixes was analytically verified by ultra high performance liquid chromatography with ultraviolet detection (UHPLC-UV) assay comparison to an independently prepared calibration solution. Each component in the ginger and kava CRMs were within 5 and 7% of the target concentrations, respectively., Conclusion: Homogeneous kava and ginger phytochemical solution mixes were produced with accurate constituent concentrations and demonstrated good stability over 2 years. These solution mixes were launched as commercially available CRMs., Highlights: These mixes can be used as accurate concentration stock solutions to prepare calibrators and controls for botanical dietary supplement product testing and standardization., (© The Author(s) 2024. Published by Oxford University Press on behalf of AOAC INTERNATIONAL. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Herein, we have reported a red-emitting 4-methyl coumarin fused barbituric acid azo dye (4-MCBA) synthesized by conventional method. Density functional theory (DFT) studies of tautomer compounds were done using (B3LYP) with a basis set of 6-31G(d,p). NLO analysis has shown that tautomer has mean first-order hyperpolarisabilities (β) value of 1.8188 × 10 -30  esu and 1.0470 × 10 -30  esu for azo and hydrazone forms, respectively, which is approximately nine and five times greater than the magnitude of urea. 4-MCBA exhibited two absorption peaks in the range of 290-317 and 379-394 nm, and emission spectra were observed at 536 nm. CV study demonstrated that the modified 4-MCBA/MGC electrode exhibited excellent electrochemical sensitivity towards the detection of catechol and the detection limit is 9.39 μM under optimum conditions. The 4-MCBA employed as a fluorescent probe for the visualisation of LFPs on various surfaces exhibited Level-I to level-II LFPs, with low background interference., (© 2024 John Wiley & Sons Ltd.)

The application of antimony sulfide sensors, characterized by their exceptional stability and selectivity, is of emerging interest in detection research, and the integration of graphitized carbon materials is expected to further enhance their electrochemical performance. This study represents a pioneering effort in the synthesis of carbon-doped antimony sulfide materials through the pyrolysis of the mixture of microorganisms and their synthetic antimony sulfide. The prepared materials are subsequently applied to electrochemical sensors for monitoring the highly toxic compounds catechol (CC) and hydroquinone (HQ) in the environment. Via cyclic voltammetry (CV) and impedance testing, we concluded that the pyrolytic product at 700 °C (Sb-700) demonstrated the best electrochemical properties. Differential pulse voltammetry (DPV) revealed impressive separation when utilizing Sb-700/GCE for simultaneous detection of CC and HQ, exhibiting good linearity within the concentration range of 0.1-140 μM. The achieved sensitivities of 24.62 μA μM -1  cm -2 and 22.10 μA μM -1  cm -2 surpassed those of most CC and HQ electrochemical sensors. Meanwhile, the detection limits for CC and HQ were as low as 0.18 μM and 0.16 μM (S/N = 3), respectively. Additional tests confirmed the good selectivity, reproducibility, and long-term stability of Sb-700/GCE, which was effective in detecting CC and HQ in tap water and river water, with recovery rates of 100.7%-104.5% and 96.5%-101.4%, respectively. It provides a method that combines green microbial synthesis and simple pyrolysis for the preparation of electrode materials in CC and HQ electrochemical sensors, and also offers a new perspective for the application of microbial synthesized materials., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Turmeric and ginger are extensively employed as functional ingredients due to their high content of curcuminoids and gingerols, considered the key bioactive compounds found in these roots. In this study, we present an innovative and fast method for the assay of curcuminoids and gingerols in different foods containing the two spices, with the aim of monitoring the quality of products from a nutraceutical perspective. The proposed approach is based on paper spray tandem mass spectrometry coupled with the use of a labeled internal standard, which has permitted to achieve the best results in terms of specificity and accuracy. All the calculated analytical parameters were satisfactory; accuracy values are around 100% for all spiked samples and the precision data result lower than 15%. The protocol was applied to several real samples, and to demonstrate its robustness and reliability, the results were compared to those arising from the common liquid chromatographic method., (© 2024 John Wiley & Sons Ltd.)

Toxicodendron vernicifluum bark has been used for many years as a component in foods and as a traditional herbal medication. Unfortunately, the presence of urushiols, which induce allergies, limits its application. This study used a vortex-blending matrix solid-phase dispersion microextraction technique to extract urushiols from Toxicodendron vernicifluum bark. HPLC was used to evaluate the amounts of the extracted urushiols (15:0, 15:1, 15:2, and 15:3). The modified magnetic adsorbent was prepared through an in situ coprecipitation method and characterized using a variety of techniques. The optimized extraction conditions are as follows: using magnetic Zeolite Socony Mobil-Five as an adsorbent, a 1:2 sample/adsorbent ratio, 2.5 min of vortex-blending time, 4 mL of 0.1% (V/V) trifluoroacetic acid-methanol as the elution solvent and 8 min of ultrasound time. There was good linearity and high repeatability in the method. Furthermore, the limits of detection for the urushiols ranged from 0.20 to 0.50 μg/mL. Under the optimized conditions, 50 compounds were identified by ultra high performance liquid chromatography and quadrupole time-of-flight mass spectrometry. These compounds included 8 phenolic acids, 9 monomeric urushiols, 11 urushiol dimers, 10 other components, and 11 flavonoids. The suggested approach, which has the advantages of few stages and high extraction efficiency over existing extraction procedures, is a potentially useful method for obtaining and evaluating urushiols in raw materials or extracts., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

This study describes the development of a highly sensitive amperometric biosensor for the analysis of phenolic compounds such as catechol. The biosensor architecture is based on the immobilization of tyrosinase (Tyr) on a screen-printed carbon electrode (SPE) modified with nanodiamond particles (ND), 1-butyl-3-methylimidazolium hexafluorophosphate (IL) and poly-l-lysine (PLL). Surface morphologies of the electrodes during the modification process were evaluated by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to investigate the electrochemical characteristics of the modified electrodes. Owing to the synergistic effect of the modification materials, the Tyr/PLL/ND-IL/SPE exhibited high sensitivity (328.2 μA mM -1 ) towards catechol with a wide linear range (5.0 × 10 -8 - 1.2 × 10 -5  M) and low detection limit (1.1 × 10 -8  M). Furthermore, the method demonstrated good reproducibility and stability. The amperometric response of the biosensor towards other phenolic compounds such as bisphenol A, phenol, p-nitrophenol, m-cresol, p-cresol and o-cresol was also investigated. The analytical applicability of the biosensor was tested by the analysis of catechol in tap water. The results of the tap water analysis showed that the Tyr/PLL/ND-IL/SPE can be used as a practical and effective method for catechol determination., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Polyphenol oxidase (PPO) is critical due to enzymatic browning in fruits and vegetables, developing economic impact in fruits industry. Metal-Organic Frameworks (MOF) have shown interesting characteristics such as water stability, low toxicity, and good adsorption yield, making them good candidates for PPO inactivation. Al-based-MOFs, MIL-53(Al), DUT-5, and MIL-110 were tested as PPO inactivators in apple juice by enzyme-MOF interactions at r.t. through two possible mechanisms, i) substrate scavengers (substrates:catechol and 4-methylcatechol) or ii) enzyme activity modifiers. The scavenging behavior of Al-based-MOFs was moderate, in the same magnitude, being catechol adsorption better than 4-methylcatechol. PPO activity was reduced by at least 70% by MIL-53(Al)/DUT-5 in 10/30 min respectively, and MIL-110 inactivated PPO in 50 min with some structural modifications. Enzyme-MOF interactions are major responsible for PPO inactivation. This could be a new applicability of MOFs, as an alternate PPO inactivation process, easily included in juice processing, retaining sensorial/nutritional properties, developed at r.t thus energy-cost-effective., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Currently, little is known about the characteristics of polyphenol oxidase from wheat bran, which is closely linked to the browning of wheat product. The wheat PPO was purified by ammonium sulfate precipitation, DEAE-Sepharose ion-exchange column, and Superdex G-75 chromatography column. Purified wheat PPO activity was 11.05-fold higher, its specific activity was 1365.12 U/mg, and its yield was 8.46%. SDS-PAGE showed that the molecular weight of wheat PPO was approximately 21 kDa. Its optimal pH and temperature were 6.5 and 35 °C for catechol as substrate, respectively. Twelve phenolic substrates from wheat and green tea were used for analyzing the substrate specificity. Wheat PPO showed the highest affinity to catechol due to its maximum V max (517.55 U·mL -1 ·min -1 ) and low K m (6.36 mM) values. Docking analysis revealed strong affinities between catechol, gallic acid, EGCG, and EC with binding energies of -5.28 kcal/mol, -4.65 kcal/mol, -4.21 kcal/mol, and -5.62 kcal/mol, respectively, for PPO. Sodium sulfite, ascorbic acid, and sodium bisulfite dramatically inhibited wheat PPO activity. Cu 2+ and Ca 2+ at 10 mM were considered potent activators and inhibitors for wheat PPO, respectively. This report provides a theoretical basis for controlling the enzymatic browning of wheat products fortified with green tea.

Background: Ginger and its extracts have been frequently used in food processing and pharmaceuticals. However, the influence of ginger and its key compounds on benzo[a]pyrene (BaP) production in meat processing has not been investigated. The purpose of this study was to explore the effect of application of ginger and its important active ingredients on BaP formation and the mechanism of inhibiting BaP formation in charcoal-grilled pork sausages., Results: The DPPH scavenging (23.59-59.67%) activity and the inhibition rate of BaP (42.1-68.9%) were significantly increased (P < 0.05) with increasing ginger addition. The active components extracted by supercritical carbon dioxide from ginger were identified by gas chromatography-mass spectrometry and 14 representative compounds (four terpenes, two alcohols, two aldehydes, four phenols and two other compounds, totaling 77.57% of the detected compounds) were selected. The phenolic compounds (eugenol, 6-gingerol, 6-paradol and 6-shogaol, accounting for 29.73% of the total composition) in ginger played a key role and had the strongest inhibitory effect on BaP (61.2-68.2%), whereas four other kinds of compound showed obviously feeble inhibitory activity (6.47-17.9%). Charcoal-grilled sausages with phenolic substances had lower values of thiobarbituric acid-reactive substances, carbonyl and diene (three classic indicators of lipid oxidation) (P < 0.05)., Conclusion: Ginger and its key compounds could effectively inhibit the formation of BaP in charcoal-grilled pork sausages. Phenolic compounds make the strongest contribution to the inhibition of Bap formation, and the inhibitory mechanism was related to the inhibition of lipid oxidation. © 2023 Society of Chemical Industry., (© 2023 Society of Chemical Industry.)

Introduction: Ginger constitutes the rhizome part of the plant Zingiber officinale from the Zingiberaceae family. A large number of ginger varieties with high sensorial and functional quality are found in Northeast India. Hence, phytopharmacological screening of different ginger varieties is essential that will serve as a guideline in applied research to develop high-end products and improve economical margins., Objective: To determine the variation in total phenolics content (TPC), total flavonoids content (TFC), and antioxidant activities and correlate that with 6-gingerol contents of different ginger varieties collected from Northeast India using Pearson's correlation analysis., Materials and Methods: The TPC and TFC values were determined using standard methods. Antioxidant activities were measured using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl radical scavenging assays, while reversed-phase high-performance liquid chromatography (RP-HPLC) analysis was utilised for quantitative determination of 6-gingerol content., Results: The result revealed that ginger variety 6 (GV6) contains the highest 6-gingerol content and TPC value showing maximum antioxidant activity, followed by GV5, GV4, GV9, GV3, GV2, GV8, GV1, and GV7. The findings also suggested that the antioxidant activity has much better correlations with TPC as compared with TFC values. Pearson's correlation analysis showed a significant correlation between 6-gingerol contents and TPC values., Conclusion: This work underlines the importance of ginger varieties from Northeast India as a source of natural antioxidants with health benefits., (© 2023 John Wiley & Sons Ltd.)

Designing MOF-based materials with desired electrochemical activity and high electron conductivity may yield a novel electrochemical sensor that effectively detects various organic pollutants and conducts health monitoring. This study developed a facile and versatile electrochemical sensor for simultaneously monitoring the environmental pollutants hydroquinone (HQ) and catechol (CT). The electrodes are fabricated by modifying a GCE with a Cu-functionalized MOF (UiO-bpydc-Cu) and multi-walled carbon nanotubes (MWCNTs). The Cu-functionalized MOF effectively improved the electronic conductivity by metalating the 2,2'-bipyridyl-derived UiO-bpydc with Cu 2+ ions. Moreover, due to the synergic effect, the composite electrode exhibits a significant voltammetric response to HQ's and CT's electro-redox. A rapid and sensitive method of synchronously detecting HQ and CT has been established by differential pulse voltammetry (DPV). The experiments reveal that the linear response ranges were 0.5-565 μM and 1-1350 μM for HQ and CT, respectively, with low detection limits of 0.361 μM and 0.245 μM. The proposed UiO-bpydc-Cu/MWCNTs/GCE electrochemical sensor shows high sensitivity, good anti-interference, reproducibility, and stability. It can also be applied for detecting HQ and CT in actual samples.

The development of a homemade carbon black composite filament with polylactic acid (CB-PLA) is reported. Optimized filaments containing 28.5% wt. of carbon black were obtained and employed in the 3D printing of improved electrochemical sensors by fused deposition modeling (FDM) technique. The fabricated filaments were used to construct a simple electrochemical system, which was explored for detecting catechol and hydroquinone in water samples and detecting hydrogen peroxide in milk. The determination of catechol and hydroquinone was successfully performed by differential pulse voltammetry, presenting LOD values of 0.02 and 0.22 µmol L -1 , respectively, and recovery values ranging from 91.1 to 112% in tap water. Furthermore, the modification of CB-PLA electrodes with Prussian blue allowed the non-enzymatic amperometric detection of hydrogen peroxide at 0.0 V (vs. carbon black reference electrode) in milk samples, with a linear range between 5.0 and 350.0 mol L -1  and low limit of detection (1.03 µmol L -1 ). Thus, CB-PLA can be successfully applied as additively manufactured electrochemical sensors, and the easy filament manufacturing process allows for its exploration in a diversity of applications., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Polyurethane (PU) prepared by blending rosin base and CO 2 -polyol already has good mechanical properties and hydrophobic effect and has powerful benefits in acid and alkali resistance and salt resistance. In this study, mussel bionic rosin-based benzoxazine (BZ) was synthesized using dehydroabietylamine, catechol, and paraformaldehyde. Mixing BZ into PU can endow the resulting PU/BZ with special effects such as zero curing shrinkage, excellent mechanical behavior, and flame retardancy through a 3D interpenetrating network system. From the results, the modulus of rupture (MOR) and modulus of elasticity (MOE) of PU wood coatings are 97.04 and 2601.97 MPa, respectively; in contrast, the PU/BZ wood coatings exhibited higher values of MOR and MOE of 110.87 and 2738.11 MPa. PU/BZ wood coatings show higher flexural strength and elastic modulus. They are also stronger than PU coatings in terms of acid/alkali and aging resistance. At the same time, the coating is endowed with flame retardant properties, and the LOI is 30.2 due to the presence of BZ. Thus, PU/BZ can be a versatile and practical wood coating. The interpenetrating network system of PU/BZ has an innovative impact on the preparation of wood coatings.

Laccase is a copper-containing enzyme that does not require hydrogen peroxide as a co-substrate or additional cofactors for an enzymatic reaction. Nanomaterials of various chemical structures are usually applied to the construction of enzyme-based biosensors. Metals, metal oxides, semiconductors, and composite NPs perform various functions in electrochemical transformation schemes as a platform for the enzyme immobilization, a mediator of an electron transfer, and a signal amplifier. We describe here the development of amperometric biosensors (ABSs) based on laccase and redox-active micro/nanoparticles (hereafter-NPs), which were immobilized on a graphite electrode (GE). For this purpose, we isolated a highly purified enzyme from the fungus Trametes zonatus , and then synthesized bi- and trimetallic NPs of noble and transition metals, as well as hexacyanoferrates (HCF) of noble metals; these were layered onto the surfaces of GEs. The electroactivity of many of the NPs immobilized on the GEs was characterized by cyclic voltammetry (CV) experiments. The most effective mediators of electron transfer were selected as the platform for the development of laccase-based ABSs. As a result, a number of catechol-sensitive ABSs were constructed and characterized. The laccase/CuCo/GE was demonstrated to possess the highest sensitivity to catechol (4523 A·M -1 ·m -2 ) among the tested ABSs. The proposed ABSs may be promising for the analysis of phenolic derivatives in real samples of drinking water, wastewater, and food products.

Hydroquinone (HQ) and catechol (CC) are important chemical raw materials in the modern industry, unfortunately, which are also high toxic phenolic pollutants. So how to achieve highly sensitive and selective determination HQ and CC is the challenge we face. In the present work, we report a facile strategy to obtain nitrogen and phosphorous co-doped glucose-derived carbon coated CoP nanowires (G-CoP/N,P-C NWs), in which nitrilotriacetic acid (NTA) was as the chelating reagent, glucose was as carbon source, and the precursors were subsequently experienced carbonization and phosphorization process. G-CoP/N,P-C NWs can shorten the distance of the electron transport and expand the reaction area, showing the intriguing electronic conductivity and electrocatalytic abilities. An electrochemical phenolic sensor based on G-CoP/N,P-C NWs is fabricated. The as-prepared sensor showcases the good sensing performance for HQ and CC with comparative linearity ranges of 0.8-900 μM (HQ) and 0.6-800 μM (CC), low limits of detections (LODs) of 0.18 μM (S/N = 3) and 0.12 μM (S/N = 3) for HQ and CC, respectively. Notably, it also displays excellent practical application for the recognition of HQ and CC in the rain water, the tap water, the domestic wastewater and the lake water, which may be a promising candidate in environmental water monitoring and drinking water safety., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Tyrosine phenol-lyase (TPL) exhibits great potential in industrial biosynthesis of l-tyrosine and its derivates. To uncover and screen TPLs with excellent catalytic properties, there is unmet demand for development of facile and reliable screening system for TPL. Here we presented a novel assay format for the detection of TPL activity based on catechol 2,3-dioxygenase (C23O)-catalyzed reaction. Catechol released from TPL-catalyzed cleavage of 3,4-dihydroxy-l-phenylalanine (l-DOPA) was further oxidized by C23O to form 2-hydroxymuconate semialdehyde, which could be readily detected by spectrophotometric measurements at 375 nm. The assay achieved a unique balance between the ease of operation and superiority of analytical performances including linearity, sensitivity and accuracy. In addition, this assay enabled real-time monitoring of TPL activity with high efficiency and reliability. As C23O is highly specific towards catechol, a non-natural product of microorganism, the assay was therefore accessible to both crude cell extracts and the whole-cell system without elaborate purification steps of enzymes, which could greatly expedite discovery and engineering of TPLs. This study provided fundamental principle for high-throughput screening of other enzymes consuming or producing catechol derivatives., (Copyright © 2022 Elsevier Inc. All rights reserved.)

This research reports, for the first time, the immobilization of an enzyme - Rhus vernificera laccase - on cashew gum (CG) nanoparticles (NPs) and its application as a biological layer in the design and development of an electrochemical biosensor. Laccase-CG nanoparticles (LacCG-NPs) were prepared by the nanoprecipitation method and characterized by UV-Vis spectrophotometry, atomic force microscopy, scanning electron microscopy, attenuated total reflectance-Fourier-transform infrared spectroscopy, circular dichroism, cyclic voltammetry, and electrochemical impedance spectroscopy. The average size and stability of the NPs were predicted by DLS and zeta potential. The ATR-FTIR results clearly demonstrated an interaction between -NH and -OH groups to form LacCG-NPs. The average size found for LacCG-NPs was 280 ± 53 nm and a polydispersity index of 0.309 ± 0.08 indicated a good particle size distribution. The zeta potential shows a good colloidal stability. The use of a natural product to prepare the enzymatic nanoparticles, its easy synthesis and the immobilization efficiency should be highlighted. LacCG-NPs were successfully applied as a biolayer in the development of an amperometric biosensor for catechol detection. The resulting device showed a low response time (6 s), good sensitivity (7.86 μA μM -1 cm -2 ), wide linear range of 2.5 × 10 -7 -2.0 × 10 -4 M, and low detection limit (50 nM).

Background: Ginger rhizome (Zingiber officinale) is a well-known spice and medicinal plant that is widely used in the Egyptian market as a spice, flavor and medicinal herb for different diseases. Since it is not cultivated as rhizomes in Egypt, ginger is imported from other countries, which may impact its quality. In this study, UV spectroscopy and high-performance liquid chromatography (HPLC) were applied as efficient available techniques for the discrimination and quality control of ginger collected from different geographical origins in combination with chemometrics. In addition, HPLC was applied to investigate the stability of ginger samples upon storage for 3 years to trace the changes in their main active constituents., Results: Data obtained from both UV and HPLC in combination with Principal Component Analysis (PCA) displayed proper discrimination of the samples according to their geographical origins. Regarding the stability study, ginger samples showed a significant decrease in quality after storage for 3 years, in which significant variation in the main pungent principles (6-, 8-, 10-gingerols and 6-shogaol) were observed. PCA failed to discriminate between ginger samples after long-time storage, so the applied model could discriminate between ginger samples before and after storage., Conclusion: UV and HPLC in combination with chemometrics can be applied as a successful tool for the study of quality, stability and geographical discrimination of ginger. © 2020 Society of Chemical Industry., (© 2020 Society of Chemical Industry.)

Rationale: Ginger pulp is the dried rhizome scraped off the skin which originates from Zingiber officinale Rosc., a Zingiberaceae plant. Ginger peel is the dried rhizome skin of Zingiber officinale Rosc. (Zingiberaceae). The present work aims to investigate the different chemical constituents that are related to the medicinal properties of the ginger pulp and ginger peel., Methods: A rapid ultra-high-performance liquid chromatography/electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UHPLC/ESI-QTOF/MS) method was developed for qualitative analysis of the constituents in different polarity extracted fractions of the pulp and peel of ginger rhizomes., Results: A total of 83 compounds were identified from the pulp and peel of ginger rhizomes, including 36 diarylheptanoids, 25 gingerols and 22 other compounds. Nine of these were new compounds. In total, 46, 27, 65 and 51 compounds were identified from the crude extract, petroleum ether, ethyl acetate, and n-butanol fractions of the ginger pulp, respectively, and 60, 30, 70 and 62 compounds were identified from the crude extract, petroleum ether, ethyl acetate, n-butanol fractions of the ginger peel, respectively. Each identified compound is marked on the corresponding chromatogram., Conclusions: The integrated method is sensitive and reliable for searching the different chemical constituents from different polarity extracted fractions of the ginger pulp and ginger peel. This work may provide a significant contribution to research into the medicinal properties of the ginger pulp and ginger peel., (© 2020 John Wiley & Sons Ltd.)

A strategy was developed to distinguish and quantitate nonfumigated ginger (NS-ginger) and sulfur-fumigated ginger (S-ginger), based on Fourier transform near infrared spectroscopy (FT-NIR) and chemometrics. FT-NIR provided a reliable method to qualitatively assess ginger samples and batches of S-ginger (41) and NS-ginger (39) were discriminated using principal component analysis and orthogonal partial least squares discriminant analysis of FT-NIR data. To generate quantitative methods based on partial least squares (PLS) and counter propagation artificial neural network (CP-ANN) from the FT-NIR, major gingerols were quantified using high performance liquid chromatography (HPLC) and the data used as a reference. Finally, PLS and CP-ANN were deployed to predict concentrations of target compounds in S- and NS-ginger. The results indicated that FT-NIR can provide an alternative to HPLC for prediction of active components in ginger samples and was able to work directly on solid samples., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Derivatization reactions are commonly used in mass spectrometry to improve analyte signals, specifically by enhancing the ionization efficiency of those compounds. Vicinal diols are one group of biologically important compounds that have been commonly derivatized using boronic acid. In this study, a boronic acid with a tertiary amine was adapted for the derivatization of vicinal diol metabolites in B73 maize tissue cross-sections for mass spectrometry imaging analysis. Using this method, dozens of vicinal diol metabolites were derivatized, effectively improving the signal of those metabolites. Many of these metabolites were tentatively assigned using high-resolution accurate mass measurements. In addition, reaction interference and cross-reactivity with various other functional groups were systematically studied to verify data interpretation., (© 2021 The Authors. Journal of Mass Spectrometry published by John Wiley & Sons Ltd.)

Catechol level is an important indicator for evaluating the quality of tea. Therefore, the exploration of a simple and efficient quantitative detection method for catechol has an important significance. In this study, functionalized graphene oxide was synthesized by chemically modifying the surface of graphene oxide. The prepared carrier was covalently combined with biomimetic oxidase iron porphyrin (FePP, the active center of horseradish peroxidase). Ionic liquid as covalent coupling agents was designed as electronic bridge between biomimetic oxidase and graphene oxide. The novel biomimetic biosensor provided a detection range of 50.0-1600.0 μmol/L by modulating under the optimal conditions of the reaction system (FePP concentration is 1.5 × 10 -3  mol/L, pH 3.0, Nafion solution dosage 1% and temperature 25 °C), the detection limit is 0.09 μmol/L. The biosensor has excellent stability, repeatability and reproducibility, and is expected to be applied to the rapid detection of catechol in actual tea sample..

In this study, metabolomics and proteomics were employed to investigate the change mechanism of nonvolatile compounds during white tea processing. A total of 99 nonvolatile compounds were identified, among which the contents of 13 free amino acids, caffeine, theaflavins, 7 nucleosides and nucleotides, and 5 flavone glycosides increased significantly, while the contents of theanine, catechins, theasinesins, 3 proanthocyanidins, and phenolic acids decreased significantly during the withering period. The results of proteomics indicated that the degradation of proteins accounted for the increase in free amino acid levels; the weakened biosynthesis, in addition to oxidation, also contributed to the decrease in flavonoid levels; the degradation of ribonucleic acids contributed to the increase in nucleoside and nucleotide levels during the withering period. In addition, the drying process was found to slightly promote the formation of white tea taste. Our study provides a novel characterization of white tea taste formation during processing., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

In this study, three psychrotolerant phenol-degrading yeast strains Candida subhashii (strain A01 1 ), Candida oregonenis (strain B02 1 ) and Schizoblastosporion starkeyi-henricii (strain L01 2 ) isolated from Rucianka peatland were examined to determine which alternative metabolic pathway for phenol biodegradation is used by these microorganisms. All yeast strains were cultivated in minimal salt medium supplemented with phenol at 500, 750 and 1000 mg l -1 concentration with two ways of conducting phenol biodegradation experiments: with and without the starving step of yeast cells. For studied yeast strains, no catechol 2,3-dioxygenase activities were detected by enzymatic assay and no products of catechol meta-cleavage in yeast cultures supernatants (GC-MS analysis), were detected. The detection of catechol 1,2-dioxygenase activity and the presence of cis,cis-muconic acid in the analyzed samples revealed that all studied psychrotolerant yeast strains were able to metabolize phenol via the ortho-cleavage pathway. Therefore, they may be tested in terms of their use to develop biotechnology for the production of cis,cis-muconic acid, a substrate used in the production of plastics (PET) and other valuable goods., (Copyright © 2020 Elsevier Inc. All rights reserved.)

A highly efficient enzyme-based sensor was made from a heteroleptic tris(phthalocyaninato) europium triple-decker complex Eu 2 (Pc)[Pc(OPh) 8 ] 2 , for the first time. The ITO working electrode was modified by a mixture of hybrid multi-layers consisting of Eu 2 (Pc)[Pc(OPh) 8 ] 2 , stearic acid (SA) and tyrosinase (Tyr) (Eu 2 (Pc)[Pc(OPh) 8 ] 2 /SA/Tyr-ITO) using the Langmuir-Blodgett (LB) technique. The microstructure and morphology of the resulting LB films can be characterized by their π-A isotherms, UV-vis absorption spectra, X-ray diffraction and atomic force microscopy (AFM) analysis. The experimental results revealed that the triple-decker molecules of Eu 2 (Pc)[Pc(OPh) 8 ] 2 take a H-type molecular stacking mode in both pure and mixed LB film, and the microstructures of films were effectively improved by mixing SA within the triple-decker Eu 2 (Pc)[Pc(OPh) 8 ] 2 molecules. The excellent electrocatalytic effect of the Eu 2 (Pc)[Pc(OPh) 8 ] 2 /SA/Tyr LB films, leads to a good linear increase from 5.26 × 10 -7 to 2.1 × 10 -4 M for catechol. It also leads to an excellent sensitivity of 2.19 μA/μM, and a detection limits of 6.29 × 10 -8 M (S/N = 3) of catehol at the oxidation peak, achieving best catechol sensing performance among the phthalocyanine-based biosensing mediators. The reduction peak also showed a good linear increase from 5.26 × 10 -7 to 1.60 × 10 -4 M for catechol with a sensitivity of 0.615 μA/μM, and a detection limit of 1.69 × 10 -7 M (S/N = 3). Moreover, the Eu 2 (Pc)[Pc(OPh) 8 ] 2 /SA/Tyr-ITO electrode are easy to reproduce, stable and resistant to interference when it comes to detection for catehol, and this indicates great potential of industrial application of tris(phthalocyaninato) rare earth complexes in ultrasensitive and specific biosensors., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Ginger is a widely consumed spice and possesses numerous pharmacological properties. However, studies addressing the efficacy of ginger in humans have been inconsistent. Many confounding factors need to be considered when evaluating the health effects from ginger against chronic diseases, especially the levels of bioactive components in the ginger formulations used in human trials. Gingerols, the major compounds in fresh ginger, are liable to dehydrate and convert to shogaols, the major compounds in dried ginger, as a result of the instability of β-hydroxyl ketone when exposed to heat and/or acidic conditions. As a result of various heating and processing methods, the concentrations of gingerols and shogaols in ginger products vary significantly. Increasing evidence has shown that gingerols and shogaols have different bioactivities, molecular targets, and metabolic pathways, suggesting the importance of identifying the optimal oral ginger composition for a specific disease. In this perspective, we highlighted differences in the composition between fresh ginger and dry ginger, bioactivities, molecular targets, and metabolic pathways of gingerols and shogaols as well as future perspectives regarding precision research on ginger.

Lignin depolymerization for the purpose of synthesizing aromatic molecules is a growing focus of research to find alternative energy sources. In current studies, the photocatalytic depolymerization of lignin has been investigated by two new iso-propylamine-based lead chloride perovskite nanomaterials ( SK9 and SK10 ), synthesized by the facile hydrothermal method. Characterization was done by Powder X-Ray Diffraction (PXRD), Scanning Electron Microscopy (SEM), UV-Visible (UV-Vis), Photoluminescence (PL), and Fourier-Transform Infrared (FTIR) Spectroscopy and was used for the photocatalytic depolymerization of lignin under UV light. Lignin depolymerization was monitored by taking absorption spectra and catalytic paths studied by applying kinetic models. The %depolymerization was calculated for factors such as catalyst dose variation, initial concentration of lignin, and varying temperatures. Pseudo-second order was the best suited kinetic model, exhibiting a mechanism for lignin depolymerization that was chemically rate controlled. The activation energy (E a ) for the depolymerization reaction was found to be 15 kJ/mol, which is remarkably less than conventional depolymerization of the lignin, i.e., 59.75 kJ/mol, exhibiting significant catalytic efficiencies of synthesized perovskites. Products of lignin depolymerization obtained after photocatalytic activity at room temperature (20 °C) and at 90 °C were characterized by GC-MS analysis, indicating an increase in catalytic lignin depolymerization structural subunits into small monomeric functionalities at higher temperatures. Specifically, 2-methoxy-4-methylphenol (39%), benzene (17%), phenol (10%) and catechol (7%) were detected by GC-MS analysis of lignin depolymerization products.

Rationale: A liquid chromatography/tandem mass spectrometry (LC/MS/MS) method has been developed and validated to determine levodopa, carbidopa, entacapone, and corresponding six related substances - levodopa impurity B, levodopa impurity C, methyldopa, methylcarbidopa, entacapone impurity C, and entacapone impurity A - in film-coated tablets for the first time., Methods: Chromatographic separation was achieved with a gradient elution by using a C18 column, a mobile phase containing 0.5% formic acid in water and 0.5% formic acid in methanol. The mobile phase flow rate was 0.5 mL min -1 . The UV detector was set at 280 nm and the triple quadrupole mass spectrometer was used in multiple reaction monitoring (MRM) mode., Results: The limit of detection (LOD) and limit of quantification (LOQ) results were 1.3 and 3.94 ng mL -1 for levodopa impurity B; 5.26 and 15.9 ng mL -1 for levodopa impurity C; 0.833 and 2.53 ng mL -1 for methyldopa; 3.31 and 10.0 ng mL -1 for methylcarbidopa; 1.67 and 5.06 ng mL -1 for entacapone impurity C; and 0.61 and 1.86 ng mL -1 for entacapone impurity A., Conclusions: The method was rapid, linear, accurate, and reproducible. The LC/MS/MS method that was developed to determine the related substances and assay of levodopa, carbidopa, and entacapone can be used to evaluate the quality of regular samples in the pharmaceutical industry. It can be also used to test the stability of samples., (© 2020 John Wiley & Sons, Ltd.)

Galactomannan, a neutral polysaccharide, was extracted from carob seeds and characterized. It was used for the first time for the fabrication of a laccase-based biosensor by the encapsulation of laccase in a chitosan+galactomannan composite. The fabricated biosensor was characterized by FTIR, scanning electron microscopy and cyclic voltammetry. The pyrocatechol detection was obtained by cyclic voltammetry measurements, through the detection of o-quinone at -0.447 V. The laccase activity was well preserved in the chitosan+galactomannan composite and the sensitivity of detection of pyrocatechol in the 10 -16 M-10 -4 M range was very high. The voltammetric response of the biosensor was stable for more than two weeks. To estimate the antioxidant capacity of olive oil samples, it was shown that the obtained laccase-based biosensor is a valuable alternative to the colorimetric Folin-Ciocalteu method.

A chimeric enzyme based on the genetic fusion of a laccase with a hydrophobin domain was employed to functionalize few-layer graphene, previously exfoliated from graphite in the presence of the hydrophobin. The as-produced, biofunctionalized few-layer graphene was characterized by electrochemistry and Raman spectroscopy, and finally employed in the biosensing of phenols such as catechol and dopamine. This strategy paves the way for the functionalization of nanomaterials by hydrophobin domains of chimeric enzymes and their use in a variety of electrochemical applications., Competing Interests: The authors declare no conflict of interest.

Currently, the large-scale and controllable fabrication of nanostructures on substrates remains a great challenge for further practical applications. In this work, a novel 3D aloe-like Au-ZnO nanocomposite was designed for in situ synthesis on an ITO substrate, achieving real-time detection of trace catechol (CC) in water. A seed-assisted hydrothermal approach was proposed to control the crystal distribution and growth direction to build a ZnO aloe-like architecture. To eliminate the natural weak conductivity of ZnO, Au nanoparticles were further deposited on all ZnO arrays to construct Au-ZnO micro/nanostructures. The synergetic effects derived from the aloe-like ZnO with a large specific area and Au nanoparticles with high conductivity resulted in both high electrocatalysis and fast electron transfer in enzymatic reactions. After laccase immobilization, the as-prepared biosensor exhibited specific recognition of catechol among other dihydroxybenzenes and phenol with an ultrahigh sensitivity of 131 μA mM -1 , as well as an extremely wide linear range from 75 nM to 1100 μM and an ultralow detection limit of 25 nM. In addition, in the detection of real lake samples, this biosensor showed satisfactory anti-interference ability and provided reliable assay results., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Phenolic compounds such as catechol are present in a wide variety of foods and beverages; they are of great importance due to their antioxidant properties. Their consumption protects against the development of certain diseases such as cancer and cardiovascular diseases. A MIP chitosan (CS) film has been electrodeposited on a boron doped diamond (BDD) electrode, by chronoamperommetry in the presence of catechol, followed by elution with 0.1 M KCl. The morphology of the MIP and non-MIP (NIP) film has been studied by AFM. The electrochemical response of the sensor analyzed by cyclic voltammetry (CV) indicates that the sensor shows excellent reproducibility (RSD = 4.1%) and repeatability (RSD = 7.0%) for catechol detection in the range of 0 to 80 μM, with a detection limit of 6.9 × 10 - 7 M and high selectivity to catechol recognition versus different phenolic compounds. The results obtained in a red wine show that it can detect catechol in a complex matrix., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

In this study, a novel spatial-resolution targeted metabolomics method was developed for a single leaf on the basis of microscale sample preparation and dansylation derivatization coupled with ultraperformance liquid chromatography-tandem mass spectrometry with a spatial resolution of 1.7 × 1.7 mm 2 . The practicability of this method was demonstrated by providing absolute quantitative within-leaf distribution information for 56 endogenous metabolites (including 8 catechins, 2 alkaloids, theanine, 4 theaflavins, 14 flavonol/flavone and their glycosides, 21 amino acids, and 6 phenolic acids). An application of this method in a mechanically pierced tea leaf indicated that astringent catechins, quercetin, and quercetin glycosides may be involved in the tea plant response to the wounding. In conclusion, the proposed novel method offered richest information on the within-leaf distribution of metabolites in tea to date and will be greatly helpful in understanding the defensive responses of tea plants against biotic and abiotic stresses., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

WS2 nanotubes functionalized with carboxylic acid functions (WS2-COOH) were used for improved immobilization of the enzyme tyrosinase in order to form an electrochemical biosensor towards catechol and dopamine. The nanotubes were deposited on glassy carbon electrodes using a dispersion-filtration-transfer procedure to assure the reproducibility of the deposits. After the electrochemical and morphological characterization of these WS2-COOH nanotube deposits, the formed biosensors showed very satisfying performance towards catechol detection with a linear range of 0.6-70 μmol L-1 and a sensitivity of 10.7 ± 0.2 mA L mol-1. The apparent Michaelis Menten constant of this system is slightly lower than the KM value of tyrosinase in solution, reflecting an excellent accessibility of the active site of the enzyme combined with a good mass transport of the target molecule through the deposit. For dopamine detection, we observed an accumulation of this substrate due to electrostatic interactions between the amine function of dopamine and the carboxylic acid groups of the nanotubes. This led to improved signal capture at low dopamine concentrations. With linear ranges of 0.5-10 μmol L-1 and 10-40 μmol L-1, and respective sensitivities of 6.2 ± 0.7 mA L mol-1 and 3.4 ± 0.4 mA L mol-1, the overall sensor performance is within the average of comparable results using carbon nanotubes. Nonetheless, the simplified handling of these nanotubes and their reduced environmental impact make these WS2-COOH nanotubes a promising nanomaterial for biosensing applications.

Biosensor platforms consisting of layer by layer films combining materials with different functionalities have been developed and used to obtain improved catechol biosensors. Tyrosinase (Tyr) or laccase (Lac) were deposited onto LbL films formed by layers of a cationic linker (chitosan, CHI) alternating with layers of anionic electrocatalytic materials (sulfonated copper phthalocyanine, CuPcS or gold nanoparticles, AuNP). Films with different layer structures were successfully formed. Characterization of surface roughness and porosity was carried out using AFM. Electrochemical responses towards catechol showed that the LbL composites efficiently improved the electron transfer path between Tyr or Lac and the electrode surface, producing an increase in the intensity over the response in the absence of the LbL platform. LbL structures with higher roughness and pore size facilitated the diffusion of catechol, resulting in lower LODs. The [(CHI)-(AuNP)-(CHI)-(CuPcS)] 2 -Tyr showed an LOD of 8.55∙10 -4 μM, which was one order of magnitude lower than the 9.55·10 -3 µM obtained with [(CHI)-(CuPcS)-(CHI)-(AuNP)] 2 -Tyr, and two orders of magnitude lower than the obtained with other nanostructured platforms. It can be concluded that the combination of adequate materials with complementary activity and the control of the structure of the platform is an excellent strategy to obtain biosensors with improved performances.

The performance of electrochemical laccase-based biosensors can be improved by immobilizing the enzyme on composite Layer-by-Layer (LbL) supports in which materials with complementary functions are combined. LbL films are formed by layers combining an electrocatalytic material which favors electron transfer (sulfonated copper phthalocyanine, CuPc S(-) ), an ionic liquid which enhances the electrical conductivity of the layers (1-butyl-3-methylimidazolium tetrafluoroborate, IL (+) ) and a material able to promote enzyme immobilization (chitosan, CHI (+) ). Composite films with different structures have been demonstrated to be efficient electrocatalysts, producing an increase in the magnitude of the responses towards catechol. The most intense and reproducible electrocatalytic effect was observed when a layer of the CuPc S(-) was placed on top of a layer formed by a mixture of CHI (+)  + IL (+) to obtain [CHI (+)  + IL (+) |CuPc S(-) ] 2 films. Biosensors with laccase immobilized on the surface of the LbL layers [CHI (+)  + IL (+) |CuPc S(-) ] 2 |Lac showed mediated electron transfer between the redox enzyme and the film and a reproducibility of device-to-device performance of 4.1%. The amperometric biosensor showed a sensitivity of 0.237 A·M -1 and a linear detection range from 2.4 μM to 26 μM for catechol. The excellent Limit of detection (LOD) of 8.96·10 -10 M (3·σ /m) is one order of magnitude lower than that obtained in similar studies. A Michaelis-Menten constant of 3.16 μM confirms excellent enzyme-substrate affinity., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2019 Elsevier B.V. All rights reserved.)

In this study, we describe the fabrication of sensitive biosensor for the detection of phenolic substrates using laccase immobilized onto two types of microporous carbon fibers (CFs). The main characteristics of microporous CFs used for preparation of biosensors are given. Two CFs were characterized by different specific surface area, CFA (<1 m 2 ·g - 1 ) and CFB (1448 m 2 ·g - 1 ), but with comparable size of the micropores estimated by positron annihilation lifetime spectroscopy. The structural analysis was shown that CFA is formed by thin interwoven fibers forming a highly porous structure, as well as CFB - by granular formations with uneven edges that shape a cellulose membrane of lower porosity. The results of amperometric analysis revealed that the laccase-bound CFs possesses better electrochemical behavior for laccase than non-modified rod carbon electrodes (control). Using chronoamperometric analysis, the operational parameters of the CFs-modified bioelectrodes were compared to control bioelectrodes. The bioelectrodes based on CFs have demonstrated 2.4-2.7 folds enhanced maximal current at substrate saturation (I max ) values, 1.2-1.4 folds increased sensitivity and twice wide linearity compared with control bioelectrodes. The sensitivity of the developed CFs-based bioelectrodes was improved compared with the laccase-bound electrodes, described in literature. The developed biosensor was tested for catechol analysis in the real communal wastewater sample., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Background: Urushiol, the culprit allergen in Toxicodendron plants such as poison ivy, is an oily mixture of 15 and 17 carbon side chain alk-(en)-yl catechols. Recently, consumer products have been identified that contain Toxicodendron as an ingredient on their label; however, no studies have assessed whether urushiol is indeed present within these products., Objective: The aim of the study was to determine whether urushiol compounds are present in consumer products labeled as containing Toxicodendron species., Methods: Gas chromatography-mass spectrometry and liquid chromatography-tandem mass spectrometry were performed on 9 consumer products labeled as containing Toxicodendron species, including topical homeopathic remedies. Single ion monitoring gas chromatography-mass spectrometry was programmed in selective ion mode to detect 3-methylcatechol characteristic fragment ions of alk-(en)-yl catechols after silanization. Similarly, single ion monitoring liquid chromatography-tandem mass spectrometry was programmed to detect 4 urushiol pentadecylcatechols and 5 urushiol heptadecylcatechols using previously reported mass-to-charge ratios., Results: Gas chromatography-mass spectrometry detected alk-(en)-yl catechols in 67% (6/9) of the products tested. Liquid chromatography-tandem mass spectrometry detected multiple urushiol pentadecylcatechols and heptadecylcatechols in 44% (4/9) of the products tested., Conclusions: Alk-(en)-yl catechols and multiple urushiols were detected in consumer products listing Toxicodendron species as an ingredient. Clinicians should be aware of these known allergenic ingredients in consumer products.