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A new approach for the hydrophobization of finished cellulosic substrates based on a previously reported enzymatic technique is proposed. Commercial finished paper was hydrophobized by using laccase from Trametes villosa in combination with lauryl gallate (LG) as hydrophobic compound. The efficiency of the method was increased by the use of a lignosulfonate as a natural dispersant to improve the surface distribution of LG on the paper, raise its hydrophobicity and help preserve the enzyme activity. No similar threefold effect from a single compound for the improvement of enzymatic treatments was previously reported. The influence of processing conditions including the LG dose, treatment time and temperature was also examined, resulting in further increased hydrophobicity. Efficient fiber bonding and chemical functionalization were confirmed by thorough washing and Soxhlet extraction of the paper. As shown here for the first time, enzyme treatments have the potential to improve the surface hydrophobicity of paper-based media., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Laccase was reacted with gallic acid in the presence of a high-kappa (91) kraft pulp. The result was a modified pulp with 34%, 20%, and 72% improvements in burst, tensile, and wet tensile strength compared to untreated control samples. Fully bleached pulps were not responsive to the laccase treatment, indicating lignin was the major target for the fiber modification. The results indicate that the strength increases were a combined effect of improvements of hydrogen bonding between fibers and creation of phenoxy radical cross-links within the sheet.

Hydrophobic properties were conferred to a high-lignin-content Kraft pulp by a laccase-catalysed treatment in the presence of lauryl gallate (LG). The treatment resulted in a two-fold increase in contact angle and conferred water absorption resistance to the pulp. Kappa number was increased, indicating that some phenolic compounds were incorporated in the pulp. A control treatment with LG alone did not affect water absorption, demonstrating that laccase was essential to attain these new properties. The loss of hydrophobicity after an acetone Soxhlet extraction highlighted that adsorbed acetone-soluble compounds played a key role in the properties. GC-FID and HPSEC-UV analysis of the acetone extract indicated the formation of dodecanol and different phenolic oligomers. SEM images showed the treatment-induced changes in the fibre network. Additional experiments with various reaction times and reactant concentrations highlighted the role of LG oxidation products in the introduction of absorption resistance., (Copyright © 2013 Elsevier B.V. All rights reserved.)

A microfluidic paper-based device (µPAD) has been combined with metal–organic frameworks (MOFs) for total phenolic compounds (TPC) quantification in fruit samples for the first time. The performance of the µPAD, based upon the vertical flow approach, was enhanced in order to determine the TPC content with high accuracy in fruit samples. The method was based on the traditional Folin-Ciocalteu Index using gallic acid or oenotannin as reference phenolic compounds. This novel design and construction of the device are in agreement with the principles of Green Chemistry avoiding wax technology (lower toxicity). The analytical parameters that affect the colorimetric method (using digital imaging of the colored zone) performance were optimized including design, sample volume, and MOF amount. Then, the analytical features of the developed method were investigated such as dynamic range (1.6–30 mg L−1), limit of detection (0.5 mg L−1), and precision (RSD < 9%). Besides, the in-field analysis is achievable with a color stability up to 6 h after the loading process of the sample and storage stability for at least 15 days without performance losses (under vacuum at − 20 °C). Furthermore, the MOF ZIF-8@paper was characterized to study its composition and the successful combination. The feasibility of the proposed method was demonstrated by determining the TPC in 5 fruit samples using oenotannin as reference solute. The accuracy was validated by comparison of the data with the results obtained with the recommended protocol proposed by the International Organisation of Vine and Wine (OIV). [ABSTRACT FROM AUTHOR]

Health benefits arising from polyphenols found in plants have driven a steady increase in the manufacture of polyphenol-rich, plant-based food products. In line with quality assurance and compliance to local and international regulations, the polyphenol content of these products needs to be ascertained by manufacturers. The measurement of the total polyphenol content (TPC) in such products, therefore, should be part of the quality assurance of food manufacturers. This study involved the development of a cheap, user-friendly, and robust paper-based device (PBD) that can be potentially used by small-to-medium enterprises (SMEs) in determining the TPC of tea-based beverages - specifically, sweet potato leaf extract-based (SPLE) tea beverage products. The PBD relies on colorimetric detection of TPC based on the iron tartrate (IT) spectrophotometric. Validation studies of the PBD yielded good accuracy and precision, with limits of detection (LOD) and quantification (LOQ) of 20.03 and 66.77 ppm gallic acid equivalents (GAE), respectively. The device also has good linearity and sensitivity. Likewise, the quantification of polyphenols using the PBD was not adversely affected by the presence of sugars and ascorbic acid. The PBD stored under refrigerated conditions remained usable for 57 d. The PBD's performance was found to be comparable to its counterpart instrumental method. [ABSTRACT FROM AUTHOR]

Cardiovascular diseases (CVDs) are serious life-threatening illnesses and significant problematic issues for public health having a heavy economic burden on all society worldwide. The high incidence of these diseases as well as high mortality rates make them the leading causes of death and disability. Therefore, finding novel and more effective therapeutic methods is urgently required. Gallic acid, an herbal medicine with numerous biological properties, has been utilized in the treatment of various diseases for thousands of years. It has been demonstrated that gallic acid possesses pharmacological potential in regulating several molecular and cellular processes such as apoptosis and autophagy. Moreover, gallic acid has been investigated in the treatment of CVDs both in vivo and in vitro. Herein, we aimed to review the available evidence on the therapeutic application of gallic acid for CVDs including myocardial ischemia-reperfusion injury and infarction, drug-induced cardiotoxicity, hypertension, cardiac fibrosis, and heart failure, with a focus on underlying mechanisms., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Abstract We report the first use of a paper-based device as a simple, low-cost and rapid detection platform for simultaneous determination of antioxidant activity and total phenolic content in food samples. Two antioxidant activity assays including 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulphonate) radical cation (ABTS) assay and cupric reducing antioxidant capacity (CUPRAC) assay and one total phenolic content assay, Folin Ciocaltue reagent (FC) assay were simultaneously employed as a proof-of-concept. The device composed of a central sample zone connected to four pretreatment zones and consecutive detection zones to accommodate all three assays and a sample blank measurement. The analysis was achieved by dropping the samples onto the sample zone to flow to the pretreatment and detection zones containing the stored reagents for each antioxidant assay making the color change that was measured using imageJ software. Assay optimization including key reagent concentrations, reaction time, and surface modification were carried out to obtain sensitive and wide linear rage analyses. Various antioxidant standards were then evaluated to determine the analytical features of the method. The paper-based assays were successfully applied to detect antioxidant activity and total phenolic content in 10 beverage samples with similar gallic acid equivalent (GAE) values to those obtained from traditional assays at a 95% confidence interval. Moreover, the GAE values of the samples obtained from three assay analyses were well correlated to each other with relatively high Pearson's correlation coefficients. These results indicated that the assays gave accurate results and are suitable for simultaneous analysis of antioxidant activity and total phenolic content in real samples. Graphical abstract fx1 Highlights • Multiple antioxidant and total phenolic content assays can be performed simultaneously on a single PAD. • Various information on antioxidant mechanisms can be obtained in one analysis. • Rapid analysis with low reagent and sample consumption for multiple antioxidant analysis. [ABSTRACT FROM AUTHOR]

This work describes a terbium luminescence‐based protocol to selectively detect gallate‐derived green tea polyphenols on a supramolecular gel immobilised paper platform for the first time. This user‐friendly, inexpensive (€ 0.0015) approach requires very low sample volumes for the analysis. The developed strategy enables simultaneous detection of gallate polyphenols in multiple tea samples with the potential for practical applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fabrication of α-glucosidase immobilized paper-based bioreactor. • High catalytic activity for immobilized α-glucosidase with C-terminus external. • Simultaneous ligand screening and visual ratiometric evaluating inhibitory activity. • Successful applications for Duzhong leaves and navel orange peels. • Molecular docking verified interactions of screened compounds to α-glucosidase. It is integral to establish methods to investigate inhibitory activity and screen inhibitors to α-glucosidase (α-Glu) from complex natural products. Here, α-Glu immobilized paper-based bioreactor platform was firstly developed for simultaneous ligand screening and visual ratiometric evaluating inhibitory activity. N-terminus of α-Glu was anchored on paper with chitosan and glutaraldehyde as cross-linking reagents. Smaller Michaelis constant (K m) for immobilized α-Glu (10.64 mM) than free α-Glu (15.63 mM) indicated higher catalytic activity. Sample (5 μL) was dropped on α-Glu immobilized paper for incubation, potent inhibitors would complex with α-Glu, while unbound compounds could be washed off. By chromatographic analyzing eluents from α-Glu and inactive α-Glu immobilized paper, potent inhibitors could be screened out. Simultaneously, activity of immobilized α-Glu was evaluated by fabricating visual ratiometric fluorescent system using ascorbic acid, Cu2+, and o -phenylenediamine without the interference of complex matrix. The developed platform was validated by model mixtures (positive control acarbose, IC 50 0.88 mg/mL; and negative control gallic acid, negligible inhibition at 5 mg/mL), and applied for real crude extracts. α-Glu inhibitory activities were visually detected for Duzhong leaves and navel orange peels (43.6 % and 26.0 % inhibition at 10 mg/mL), and four flavonoids were screened, identified, and verified as α-Glu inhibitors. Further, molecular docking studies revealed the possible inhibitory mechanisms, which came from the significant affinity interaction by forming hydrogen bonds. Results suggested the convenience, specificity, reliability, and efficiency of the proposed method. [ABSTRACT FROM AUTHOR]

Mechanically robust graphene papers with both high gravimetric and volumetric capacitances are desired for high-performance energy storages. However, it’s still a challenge to tailor the structure of graphene papers in order to meet this requirement. In this work, a kind of chemical-reduction-tailored mechanically-robust reduced graphene oxide/carbon nanotube hybrid paper has been reported for high-performance electrochemical capacitive energy storages. Gallic acid (GA), as an excellent reducing agent, was used to reduce graphene oxide. Through vacuum filtration of gallic acid reduced graphene oxide (GA-rGO) and carboxylic multiwalled carbon nanotubes (MWCNTs) aqueous suspensions, mechanically robust GA-rGO/MWCNTs hybrid papers were obtained. The resultant hybrid papers showed high gravimetric capacitance of 337.6 F g −1 (0.5 A g −1 ) and volumetric capacitance of 151.2 F cm −3 (0.25 A cm −3 ). In addition, the assembled symmetric device based on the hybrid papers exhibited high gravimetric capacitance of 291.6 F g −1 (0.5 A g −1 ) and volumetric capacitance of 136.6 F cm −3 (0.25 A cm −3 ). Meanwhile, it exhibited excellent rate capability and cycling stability. Above all, this chemical reduction tailoring technique and the resultant high-performance GA-rGO/MWCNTs hybrid papers give an insight for designing high-performance electrodes and hold a great potential in the field of energy storages. [ABSTRACT FROM AUTHOR]

In this work, the design and development of a microfluidic paper-based device (μPAD) for the quantification of total phenolic compounds (TPC) in wines is described. The developed μPAD was based upon the vertical flow concept and the colour reaction used was the known Folin-Ciocalteu reaction using gallic acid as reference phenolic compound. After studying operational parameters, namely type of paper, reagents and sample volume, a dynamic range of 5–50 mg L−1 was obtained with a limit of detection of 1.2 mg L−1. The described device proved to have good precision (relative standard deviation < 5%) and no significant interferences were observed from known compounds present in wines. Furthermore, the stability of the colour product and of the device itself were assessed; the μPAD was stable for 30 days (in the dark at room temperature) and it could be scanned up to 8 h after sample introduction. The developed μPAD pose as a simple method for TPC quantification and was successfully applied to several wine samples including sparkling and table wines with two different approaches: i) using gallic acid as reference compound with standard addition; and ii) using taniraisin with external calibration. The accuracy of the proposed μPAD method was assessed by comparison with the reference spectrophotometric method according to the International Organisation of Vine and Wine (OIV) recommendations. [Display omitted] • A μPAD method has been developed for total phenolic compounds quantification. • Vertical-flow design using Folin-Ciocalteu reaction was employed. • After the optimization, μPAD cards were successfully applied to wine samples. • The device was portable, cost-effective and user-friendly. [ABSTRACT FROM AUTHOR]

[Display omitted] • 3D paper-based microfluidic electrochemical device (3D-ePAD) was constructed. • Graphite-supported gold nanoparticles modified electrode was used as a working electrode. • Low-cost, disposable, simple, and miniaturized 3D-ePAD was performed for determination of GA in tea samples. The combination of µPAD with electrochemical transducers has gained advantages of miniaturization, high sensitivity, selectivity, simplicity of instrumentation, portability, rapid analysis, and so on. In this work, the development of a 3D paper-based microfluidic electrochemical device (3D-ePAD) for the determination of gallic acid (GA) was presented. The 3D-ePAD is composed of three electrodes (working, reference, and counter electrodes) in which the hydrophilic area of the working electrode was manually screen-printed and modified with graphite-supported AuNPs(AuNPs/C) ink. The evaluation of the electrochemical oxidation process of GA at modified and unmodified electrodes at 3D-ePAD indicated the improvement of anodic current responses at the AuNPs/C modified electrode which can be attributed to the intermolecular hydrogen-bonded network between AuNPs and GA. For quantitative determination of GA, the amperometric experiments were investigated under optimal conditions in which a linear relationship between the GA concentration and the recorded current was achieved. The sensor displays a good linear range of 1.0 to 100.0 μM and 0.1 to 2.0 mM for GA determination. The limit of detection (LOD) of 0.89 μM was achieved for GA by 3D-ePAD. Conclusively, the 3D-ePAD was performed successfully for the determination of GA in tea samples. [ABSTRACT FROM AUTHOR]

In this study, the effect of bay laurel and rosemary leaf extracts in two forms, free and nanoliposome, on the chemical indices of spoilage (TVB-N) and (TBA) in minced Silver carp fish was investigated. Extracts were evaluated for phenolic and flavonoid compounds. The treatments studied in minced Silver carp fish included control treatment, treatments containing 1 and 1.5% of free extract of Laurus nobilis leaves and Rosemary and treatments containing 1 and 1.5%. It is one of the liposome-coated extracts that was tested at refrigerator temperature at 0, 4, 8 and 12 days with 3 replications. The results showed that the amount of phenolic and flavonoid compounds in rosemary extract was more favorable than fragrant leaves. The aqueous extract of rosemary had higher levels of phenolic (344.66 mg gallic acid / g extract) and flavonoid (245.33 mg Rutin / g extract) compounds compared to the bay laurel extract (257.66 mg gallic acid / g extract) and (151.26 mg Rutin / g extract) respectively. The results of chemical changes in minced Silver carp showed that with increasing the storage time of fish at refrigerator temperature, the mentioned parameters increased, but nevertheless, in the treatment containing the finely coated form of two plants, Laurus nobilis leaves and rosemary (concentration 1.5%), The changes were significantly slower than other treatments, and according to the results, it can be concluded that in general, the addition of extracts Odor of Laurus nobilis and rosemary leaves in a concentration of 1.5%, maintains the quality of Silver carp fish in terms of chemical quality indicators. [ABSTRACT FROM AUTHOR]

Many western manuscripts were written using iron gall inks. These inks can damage the paper via two major mechanisms: (a) acid hydrolysis, enhanced by humidity, and (b) oxidative depolymerization provoked by the presence of oxygen and free iron(II) ions. The degradation of unsized Whatman paper impregnated with different combinations of iron sulfate, gallic acid, and gum arabic was studied at room temperature in order to assess the relative importance of each mechanism. The samples were stored in various environments including a dry and/or an oxygen-free atmosphere. The cellulose depolymerization was monitored by viscometry and related to changes in the oxidation state of iron, determined by X-ray absorption near-edge spectrometry. The results indicate that residual amounts of oxygen (less than 0.1%) promote cellulose depolymerization, whereas the level of relative humidity has no impact. The cellulose depolymerization also appears closely correlated to oxidative mechanisms. Regarding the oxidation of iron, it only occurs in the simultaneous presence of oxygen and moisture, suggesting the occurrence of rustlike oxidative mechanisms. Finally, the presence of gallic acid has a strong influence, which is only partially explained by its capacity to reduce iron(III) to iron (II). [ABSTRACT FROM AUTHOR]

• The first μPADs-based kinetic matching approach for total polyphenol content measurement. • Identical reaction progress achieved on-chip without external facility assistance. • Rapid detection of total polyphenol content of tea within ten minutes. In this work, a facile kinetic matching approach for total polyphenol content (TPC) measurement was developed based on the adoption of microfluidic paper-based analytical devices with symmetric channel distribution. A set of Folin-Ciocalteu reactions performed on the same paper chip were activated all at the same time through synchronized filling of sodium carbonate solution among individual channels. Gallic acid was found valid as a standard compound for kinetic matching measurement of tea samples. TPC of tea infusions was successfully measured within ten minutes without any complexed time control procedure needed. Under the optimized conditions, the new developed method showed good linearity in the TPC range of 10–100 mg/L (r > 0.9955) and the inter-chip precision was 5.6% (n = 11). The results measured with the new developed approach were in good agreement with those with the conventional FC assay. [ABSTRACT FROM AUTHOR]

Many gallate esters have been applied as food additives due to their good biological properties. Herein, nine novel gallate ester derivatives were synthesized by a Friedel-Crafts alkylation reaction and characterized by melting point (m.p.), infrared (IR) spectroscopy, nuclear magnetic resonance ( 1 H- and 13 C-NMR) spectra, and high-resolution mass spectrometry (HR-ESI-MS). Their antioxidant and antibacterial activities were measured using a series of classical assays. Studies found that the products showed favorable antioxidant and antibacterial activities. Their 1,1-diphenyl-2-picrylhydrazyl free radical (DPPH ⋅ ) scavenging effect IC 50 values were less than 5.00 μg mL -1 and their reducing power was not less than that of vitamin C (Vc). Furthermore, the antibacterial results showed that the minimum inhibitory concentration (MIC) values of the products were not greater than 8.00 μg mL -1 , and their antibacterial rates were over 95 % at 300 μg mL -1 . The above data add valuable and novel information that gallate ester derivatives can be considered potential food additives to address food safety issues because of their high biological activity and health benefits., (© 2021 Wiley-VHCA AG, Zurich, Switzerland.)

Herein, a novel paper-based chemiluminescence (CL) assay is reported using a smartphone readout for on-site and reliable analytical applications. The CL system was based on the high-performance improving effect of cobalt-imidazole metal-organic framework (CoMOF) on luminol-hydrogen peroxide (H 2 O 2) CL emission. The CoMOF was grown on paper and used as a support for the CL reaction, which led to an intense CL emission and good reproducibility. More importantly, the stability of luminol, as the CL reagent, was greatly improved in the presence of CoMOF. This high stability, along with the high-yield CL emission, makes the device highly suitable for commercialization. Furthermore, using a smartphone as the detector for the developed device made the process easier and more accessible for public usage. In this work, the new paper-based CL smartphone device was used for the detection of the total phenolic content of food samples. Phenolic compounds (PC) are hydroxyl radical scavengers that can effectively quench the CL emission of the luminol–H 2 O 2 –CoMOF system. After optimizing the reaction conditions, the system could detect PC at the μg mL−1 level. Detection limits of 0.12, 0.28, 0.46, 0.85, and 1.23 μg mL−1 were obtained for gallic acid, quercetin, catechin, kaempferol, and caffeic acid, respectively. This work is the first report on the practical application of smartphone CL assays for the estimation of PC. The proposed assay is an easy-to-use, low-cost, portable, and suitable assay for on-site screening purposes. [Display omitted] • Efficient improving effect of a Cobalt MOF (CoMOF) on luminol-H 2 O 2 CL emission. • Direct synthesis of CoMOF on the paper to improve the reproducibility of CL signal. • Development of a simple paper-based CL analytical device with a smartphone readout. • The great advantages of the device make it suitable for public usage. • Application of the new smartphone assay to measure the total phenolic content of foods. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate the anti-inflammatory and antiproliferative effect of syringic acid (SRA) on oral squamous cell carcinoma (OSCC) SCC131 cells via suppression of NF-κB-induced PI3K/Akt signalling pathway., Methods: The present study assesses the anticancer effects of SRA alongside human oral cancer (HOC) SCC131 cells through the fabrication of reactive oxygen species (ROS) and activated apoptosis. DAPI and Rh-123 staining were used to assess the apoptotic nuclear characteristic, mitochondrial membrane potential, cell adhesion and migration by fluorescence microscope with SRA treatment., Key Findings: Syringic acid inhibits cell viability (IC 50 values of 25 µm), adhesion, migration and induced apoptosis. MTT assay demonstrated SRA-induced apoptotic events, inhibition of invasion and angiogenic signalling in SCC131 cell line. Furthermore, SRA treated with SCC131 cells suppresses the protein expression of inflammatory, angiogenesis and PI3K/Akt signalling pathways. It is suggested that SRA prevents the translocation of NF-κB and PI3K/Akt activated products to the nucleus, thereby suppressing angiogenesis via downregulation of vascular endothelial growth factor., Conclusions: Therefore, addition of SRA to SCC131 cells may provide a promising natural therapeutic strategy against squamous cell carcinomas with potential application in clinical analysis., (© 2020 Royal Pharmaceutical Society.)

No abstract received. [ABSTRACT FROM AUTHOR]

• A paper-based chemosensor with smartphone reflectometry detection relying on the F C assay was developed for direct total polyphenols analysis. • 3D printing and PDMS replica molding technologies were used to develop all-in-one analytical device for on-site polyphenols quantification. • The chemosensor has been applied to measure polyphenols in extra virgin olive oil and aqueous food matrices. High polyphenols levels are one of the main quality characters of Extra Virgin Olive Oil (EVOO), leading to high antioxidant activity and contributing to the EVOO health beneficial effects. Analytical methods for the rapid assessment of EVOO polyphenols content, possibly directly at the place of production or distribution, are therefore important for the commercial enhancement of this product. Unfortunately, most analytical methods for quantification of polyphenols in EVOO require laboratory instrumentation and preliminary sample extraction procedures. In this paper we describe a paper-based chemosensor based on the well-known Folin-Ciocalteu colorimetric assay for the rapid (assay time 15 min) quantitative detection of polyphenols in EVOO without any preliminary sample extraction. Use of n-propanol for diluting the EVOO sample allows its direct analysis on paper supports loaded with the Folin-Ciocalteu reagent. The color change of the paper supports is measured using a smartphone camera. A disposable analytical cartridge containing all necessary reagents, including calibration standards, and accessories for performing the assay using a Samsung S8 smartphone have been developed to perform on-site analysis. Measurement of total polyphenol content of EVOO samples gave results in good agreement with the conventional Folin-Ciocalteu assay, and the limit of detection was 30 μg gallic acid equivalents g−1 EVOO. The same approach can be employed to measure polyphenols in other oils of vegetal origin. [ABSTRACT FROM AUTHOR]