A Novel Galantamine-Curcumin Hybrid as a Potential Multi-Target Agent against Neurodegenerative Disorders

The acetylcholinesterase (AChE) inhibitors are the main drugs for symptomatic treatment of neurodegenerative disorders like Alzheimer’s disease. A recently designed, synthesized and tested hybrid compound between the AChE inhibitor galantamine (GAL) and the antioxidant polyphenol curcumin (CU) showed high AChE inhibition in vitro. Here, we describe tests for acute and short-term toxicity in mice as well as antioxidant tests on brain homogenates measured the levels of malondialdehide (MDA) and glutathione (GSH) and in vitro DPPH, ABTS, FRAP and LPO inhibition assays. Hematological and serum biochemical analyses were also performed. In the acute toxicity tests, the novel AChE inhibitor given orally in mice showed LD₅₀ of 49 mg/kg. The short-term administration of 2.5 and 5 mg/kg did not show toxicity. In the ex vivo tests, the GAL-CU hybrid performed better than GAL and CU themselves; in a dose of 5 mg/kg, it demonstrates 25% reduction in AChE activity, as well as a 28% and 73% increase in the levels of MDA and GSH, respectively. No significant changes in blood biochemical data were observed. The antioxidant activity of 4b measured ex vivo was proven in the in vitro tests. In the ABTS assay, 4b showed radical scavenging activity 10 times higher than the positive control butylhydroxy toluol (BHT). The GAL-CU hybrid is a novel non-toxic AChE inhibitor with high antioxidant activity which makes it a prospective multitarget drug candidate for treatment of neurodegenerative disorders.

Synthesis of novel antioxidant and antitumor 5-aminopyrazole derivatives, 2D/3D QSAR, and molecular docking

5-Aminopyrazole serves as a vital precursor for several biologically active pyrazoloazines, including pyrazolopyridine, pyrazolopyrimidine, and pyrazolotriazine, as well as Schiff bases, thiourea, and phthalimide derivatives. In this study, we structurally characterized novel pyrazole derivatives by spectral IR, ¹H and ¹³C NMR, and MASS spectroscopy. We also evaluated antioxidant activity of various derivatives using ABTS and DPPH methods and cytotoxicity in the hepatocellular carcinoma Hep-G2 cells by SRB assay. The most potent antitumor molecules were 5-aminopyrazole derivative 3, chloroacetanilide derivative 8, maleimide derivative 10a, pyrazolopyrimidine 16, and enamine 19, with IC₅₀ values of 41, 3.6, 37, 24.4, and 17.7 μM, respectively. Complementary computational studies predicted QSAR and bioactivity of these molecules. Interestingly, the most effective compounds were also predicted to be kinase inhibitors; in addition, molecular docking with liver receptors (3MBG, 4XCU, and 4G9C) predicted promising interactions.

Redox-based colorimetric sensing of H2O2 after removal of antioxidants with ABTS radical oxidation

Monitoring and determining H₂O₂ in many industries, treatment plants and biochemical media is important because of its harmful effects even at low concentrations. This work proposes a redox-based colorimetric sensor for the determination of hydrogen peroxide in the presence of antioxidants which are known interferents causing positive errors. On the other hand, the widely used peroxidase-based methods are interfered by enzyme inhibitors. The proposed method consists of two stages, namely antioxidant removal and H₂O₂ determination. In the first step, antioxidants were removed simply using ABTS radical (ABTS⁺) oxidant produced by persulfate. After antioxidant elimination, H₂O₂ in samples was determined by using the CUPRAC colorimetric sensor. The CUPRAC reagent, copper (II)-neocuproine (Cu(II)-Nc), immobilized on a Nafion persulfonate membrane was used for sensor preparation. The light blue Cu(II)-Nc was reduced by H₂O₂ to the yellow-orange colored Cu(I)-Nc chelate on the sensor, and the absorbance increase at 450 nm was recorded. The LOD and the LOQ values obtained for H₂O₂ were 0.33 and 1.10 µM, respectively. The proposed assay was validated in terms of linearity, additivity, precision and recovery. The H₂O₂ contents of spiked food extracts, synthetic serum and certain commercial products (i.e. food sterilization solution, whitening toothpaste and hair bleaching solution) were found to be comparable to the results of peroxidase-ABTS and titanyl sulfate reference assays. In addition, peroxide-type explosive triacetone triperoxide (TATP) was successfully determined in the presence of amine-type antioxidants. The proposed simple and low-cost assay is not inhibited by environmental agents (heavy metals, pesticides, sulfhydryl agents, etc.) adversely affecting enzymatic methods. It is additionally insensitive to turbidity and colored components of complex samples.

Chemical composition, in vitro antioxidant, anticholinesterase, and antidiabetic potential of essential oil of Elaeagnus umbellata Thunb

Background

Elaeagnus umbellata Thunb. (autumn olive) is a high valued medicinal plant. It belongs to Elaeagnaceae family and is widely distributed in Himalayan regions of Pakistan. In the present study essential oil were extracted from the fruit of this plant and their antioxidant, anticholinesterase and antidiabetic potentials were also evaluated.

Methods

Essential oils were extracted from the fruit of E. umbellata using hydro-distillation method and were characterized by GC-MS. The extracted oil were tested for its antioxidant, anticholinesterase, and antidiabetic potentials using standard protocols.

Results

About 68 compounds were identified by GC-MS. The extracted oil exhibited a fairly high free radical scavenging activities against DPPH and ABTS radicals with IC₅₀ values of 70 and 105 μg/mL respectively (for ascorbic acid, used as standard, the IC₅₀ values were 32 and 29 μg/mL, respectively against the mentioned radicals). The essential oil also exhibited anticholinesterase activities with IC₅₀ values of 48 and 90 μg/mL respectively against AChE and BChE (for galantamine used as standard, the IC₅₀ values were 25 and 30 μg/mL respectively). The essential oil also exhibited antidiabetic potential with IC₅₀ values of 120 and 110 μg/mL respectively against α-glucosidase and α-amylase (IC₅₀ values for standard acarbose = 28 and 30 μg/mL respectively).

Conclusion

Essential oil extracted from the fruits of E. umbellata exhibited reasonable antioxidant, anticholinesterase, and antidiabetic potentials that could be used as alternative medicine in treating diabetes and neurodegenerative disorders. However, further studies are needed to isolate responsible compounds and evaluate the observed potential in animal models.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-021-03228-y.

Phytochemical Analysis, In Vitro Anticholinesterase, Antioxidant Activity and In Vivo Nootropic Effect of Ferula ammoniacum (Dorema ammoniacum) D. Don. in Scopolamine-Induced Memory Impairment in Mice

Background: Ferula ammoniacum (D. Don) is one of the endemic medicinal plants that is traditionally used to treat a number of diseases. Although the plant has been used to enhance memory, the investigational evidence supporting the nootropic effect was unsubstantial. Hence, the rationale for this study was to assess the potential beneficial effect of F. ammoniacum seed extracts on learning and memory in mice. Methods: The powdered plant samples (aerial parts) were subjected to extraction ad fractionation. Among the extracts, crude and ethyl acetate extracts were screened for major phytochemicals through HPLC analysis. All the extracts were evaluated for the in vitro anticholinesterase (AChE and BChE) and antioxidant potentials. Among the extracts the active fraction was further assessed for improving learning and memory in mice using behavioural tests like Y-maze and novel object recognition test (NORT) using standard protocols. After behavioural tests, all the animals were sacrificed and brains tissues were assessed for the ex vivo anticholinesterase and antioxidant potentials. Results: Phytochemicals like chlorogenic acid, quercetin, mandelic acid, phloroglucinol, hydroxy benzoic acid, malic acid, epigallocatechin gallate, ellagic acid, rutin, and pyrogallol were identified in crude methanolic extract (Fa.Met) and ethyl acetate fraction (Fa.EtAc) through HPLC. Fa.EtAc and Fa.Chf extracts more potently inhibited AChE and BChE with IC50 values of 40 and 43 µg/mL, and 41 and 42 µg/mL, respectively. Similarly highest free radical scavenging potential was exhibited by Fa.EtAc fraction against DPPH (IC50 = 100 µg/mL) and ABTS (IC50 = 120 µg/mL). The extract doses, 100 and 200 mg/kg body weight significantly (p < 0.01) improved the short-term memory by increasing the percent spontaneous alternation in the Y-maze test along with increasing discrimination index in the NORT that clearly indicated the enhancement in the recognition memory of mice. Conclusion: The extracts more potently scavenged the tested free radicals, exhibited anticholinesterase activities, improved the learning abilities and reduced the memory impairment induced by scopolamine in mice model thus suggesting that these extracts could be effectively used for the management of oxidative stress, neurodegenerative diseases and memory loss.

Hypericum perforatum L.-Mediated Green Synthesis of Silver Nanoparticles Exhibiting Antioxidant and Anticancer Activities

This contribution focuses on the green synthesis of silver nanoparticles (AgNPs) with a size < 100 nm for potential medical applications by using silver nitrate solution and Hypericum Perforatum L. (St John’s wort) aqueous extracts. Various synthesis methods were used and compared with regard to their yield and quality of obtained AgNPs. Monodisperse spherical nanoparticles were generated with a size of approximately 20 to 50 nm as elucidated by different techniques (SEM, TEM). XRD measurements showed that metallic silver was formed and the particles possess a face-centered cubic structure (fcc). SEM images and FTIR spectra revealed that the AgNPs are covered by a protective surface layer composed of organic components originating from the plant extract. Ultraviolet-visible spectroscopy, dynamic light scattering, and zeta potential were also measured for biologically synthesized AgNPs. A potential mechanism of reducing silver ions to silver metal and protecting it in the nanoscale form has been proposed based on the obtained results. Moreover, the AgNPs prepared in the present study have been shown to exhibit a high antioxidant activity for 2, 2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) radical cation, and super oxide anion radical and 2,2-diphenyl-1-picrylhydrazyl. Synthesized AgNPs showed high cytotoxicity by inhibiting cell viability for Hela, Hep G2, and A549 cells.

Insecticidal Activity and Free Radical Scavenging Properties of Isolated Phytoconstituents from the Saudi Plant Nuxia oppositifolia (Hochst.)

Chromatographic purification of the alcoholic extract from the aerial parts of the Saudi plant Nuxia oppositifolia (Hochst.), Benth., resulted in five isolated phenolic compounds. Two flavones, hispidulin (1) and jaceosidin (2), and the phenylethanoid glycosides, verbascoside (3), isoverbascoside (4), and conandroside (5), were identified and their chemical structures were determined by spectroscopic analyses. The insecticidal activity of compounds 1 and 2, in addition to 11 compounds isolated in a previous research (6-16), was evaluated against the Yellow Fever mosquito, Aedes aegypti. Four compounds displayed adulticidal activity with LD₅₀ values of 2-2.3 μg/mosquito. Free radical scavenging properties of the plant extracts and compounds (1-5) were evaluated by measuring the 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonate radical cation (ABTS^•+) scavenging activity. All compounds exhibited notable activity, compared with the positive control, l-Ascorbic acid. This study suggests that N. oppositifolia could be a promising source of secondary metabolites, some with lethal adulticidal effect against Ae. aegypti.

Comparison of antioxidant capacities and antioxidant components of commercial bitter melon (Momordica charantia L.) products

In this study, the total phenolic contents and total antioxidant capacities of some commercial bitter melon products (powder, packaged powder, capsule, paste in olive oil), and of unripe and ripe fruits were determined by spectrophotometric and chromatographic methods. The total antioxidant capacities of unripe and ripe bitter melon samples, determined by using the CUPRAC (cupric reducing antioxidant capacity assay) and ABTS (2,2′-azino-bis(3-ethylbenzthiazolin-6-sulfonic acid))/HRP (horseradish peroxidase) methods, were 42.5 and 36.3 µmol TRE (Trolox equivalent) g–1, and 8.7 and 7.0 µmol TRE g–1, respectively. The TAC (total antioxidant capacity) order of the studied samples using the same 2 methods were determined as follows: capsule (CUPRAC value, 140.8; ABTS/HRP value, 143.6 µmol TRE g–1) > packaged powder (129.6; 126.1) > powder (52.3; 64.3) > unripe fruit (42.5; 36.3) > paste in olive oil (17.6; 14.4) > ripe fruit (8.7; 7.0). The order of phenolic content was found as follows: unripe fruit (193.2 µmol GAE (gallic acid equivalent) g-1) > capsule (162.0) > packaged powder (160.6) > powder (83.6) > paste in olive oil (38.3) > ripe fruit (14.6).

Substrate specificity of a new laccase from Trametes polyzona WRF03

Various aromatic compounds that are structurally analogous to lignin were tested as possible/preferred substrates for purified laccase from newly isolated white rote fungi, Trametes polyzona WRF03. The pH optima were tested using different substrates and kinetic studies were conducted at these pH optima. The pH optima in the presence of ABTS, α-naphthol, o-dianisidine, and catechol were 4.5 but 5.0 and 5.5 in the presence of guaiacol and pyrogallol, respectively. The initial velocities obtained from the kinetic study were analyzed using Graph Pad Prism 7 and Lineweaver-Burk plot to obtain kinetic constants (k_m and _Vmax) which were used to calculate substrate specificity. Amongst all the substrates tested, ABTS had the highest specificity-constant (181.51 M⁻¹s⁻¹), and therefore, the most preferred substrate was followed by α-naphthol, o-dianisidine, guaiacol, pyrogallol, and catechol. Resorcinol, orcinol, and veratryl alcohol did not display any considerable chemical shift in the presence of Trametes polyzona WRF03 laccase. Also, oxidation of phenolic substrates appeared to be dependent on the nature of the substituent groups and their relative position on the aromatic nucleus. Since most of these substrates are structural analogs of lignin and many recalcitrant environmental pollutants, the enzyme may find application in delignification, treatment of wastewater containing dyes, and polycyclic aromatic hydrocarbons (PAHs).

Preharvest Methyl Jasmonate Treatment Increased the Antioxidant Activity and Glucosinolate Contents of Hydroponically Grown Pak Choi

Vertical hydroponics farming has emerged as an alternative solution to feed the continuously growing world population. Additionally, recent studies reported that the exogenous treatments of jasmonic acid influence the phytochemical composition of Brassicaceae. We conducted this study to determine the effect of preharvest methyl jasmonate (MeJA) treatment on the phytochemical composition and antioxidant activities of soil- and hydroponically grown pak choi. An aqueous solution of 0.5-mM MeJA was sprayed to saturation on the aerial plant part three days before harvest. The harvested pak choi was freeze-dried and then powdered to measure the antioxidant activity and the contents of chlorophylls (Chls), total phenolics and flavonoids, and glucosinolates (GSLs). The overall results revealed that pak choi grown in vertical hydroponics had higher total Chls and total phenolics than those grown in soil in the greenhouse, regardless of MeJA treatment. Nevertheless, the GSLs content and total flavonoids increased significantly due to MeJA treatment in both growing systems, and the highest values were recorded in hydroponically grown MeJA-treated pak choi. Similarly, the 2, 2-di-phenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity, Trolox-equivalent antioxidant capacity (ABTS), oxygen radical absorbance capacity (ORAC), and ferric-reducing antioxidant power (FRAP) were highest in hydroponically grown MeJA-treated pak choi. Taken together, the preharvest foliar treatment of MeJA can be used to improve the phytochemical composition of pak choi grown in both growing systems. Interestingly, the results strongly support the use of MeJA treatment in the vertical hydroponics growing system compared to the conventional growing system in the soil. This indicates that supplementing the vertical hydroponic growing system with preharvest MeJA treatment could be the best option to improve both the yield per square meter and the quality of pak choi. Besides, MeJA-treated pak choi could be used as a value-added horticultural commodity, as its antioxidant activity increased after treatment. Moreover, after further studies, MeJA could also be applied to other Brassica vegetables to improve their GSL contents and antioxidant properties.

A reliable, quick and universally applicable method for monitoring aptamer SELEX progress

Nucleic acid aptamers for biosensing are developed from a complex ssDNA library through Systematic Evolution of Ligands by Exponential Enrichment (SELEX) process. Monitoring of SELEX process is crucial for generating high-affinity aptamers. Extant methods for monitoring aptamer selection are either arduous or give false-positive signals, which adversely impact the outcome of selection. We describe a colorimetric, simple and cost-effective, novel method to monitor the progress of in vitro selections. The power of rolling circle amplification (RCA) and inherent Horse Radish Peroxidase (HRP)-mimicking activity of G-quadruplex/hemin DNAzyme were employed to produce a colorimetric signal. A unique extension of DNA population at 3'-OH end by PCR generated concatenated repeats by rolling circle amplification (RCA) reaction. Oxidation of substrate ABTS (2, 2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)) in presence of H₂O₂ and hemin cofactor produced colorimetric signal. Analysis of the signal generated by the DNA pool bound to their target provided a quantitative measurement of SELEX. We demonstrate the reproducibility and accuracy of the method by evaluating the progress of two discrete selections.

Co-immobilization of laccase and ABTS onto amino-functionalized ionic liquid-modified magnetic chitosan nanoparticles for pollutants removal

This work aims to achieve the co-immobilization of laccase and 2,2-binamine-di-3-ethylbenzothiazolin-6-sulfonic acid (ABTS) to improve removal capability of the biocatalyst for pollutants while avoiding potential pollution caused by ABTS. The laccase was immobilized on magnetic chitosan nanoparticles modified with amino-functionalized ionic liquid containing ABTS (MACS-NIL) based on Cu ion chelation (MACS-NIL-Cu-lac). The carrier was characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, x-ray diffraction and etc., and electron paramagnetic resonance confirmed the mediator molecule ABTS on the carrier could also play the role of electron transmission. MACS-NIL-Cu-lac presented relatively high immobilization capacity, enhanced activity (1.7-fold that of free laccase), improved pH and temperature adaptability, and increased thermal and storage stability. The removal performance assay found that MACS-NIL-Cu-lac had a good removal efficiency with 100.0 % for 2,4-dichlorophenol in water at 25 °C, even when the concentration reached 50 mg/L. Reusability study showed that after six catalytic runs, the removal efficiency of 2,4-dichlorophenol by MACS-NIL-Cu-lac could still reach 93.2 %. Additionally, MACS-NIL-Cu-lac exhibited higher catalytic efficiencies with 100.0 %, 70.5 % and 93.3 % for bisphenol A, indole, and anthracene, respectively. The high catalytic performance in pure water system obtained by the novel biocatalyst co-immobilizing laccase and electron mediator ABTS showed greater practical application value.

amazonica Ducke) Essential Oil: Chemical Composition, Antibacterial, Antioxidant and Antitrypanosomal Activity

Aniba rosaeodora is one of the most widely used plants in the perfumery industry, being used as medicinal plant in the Brazilian Amazon. This work aimed to evaluate the chemical composition of A. rosaeodora essential oil and its biological activities. A. rosaeodora essential oil presented linalool (93.60%) as its major compound. The A. rosaeodora essential oil and linalool showed activity against all the bacteria strains tested, standard strains and marine environment bacteria, with the lower minimum inhibitory concentration being observed for S. aureus. An efficient antioxidant activity of A. rosaeodora essential oil and linalool (EC₅₀: 15.46 and 6.78 µg/mL, respectively) was evidenced by the inhibition of the 2,2-azinobis- (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical. The antitrypanosomal activity of A. rosaeodora essential oil and linalool was observed at high concentrations against epimatigote forms (inhibitory concentration for 50% of parasites (IC₅₀): 150.5 ± 1.08 and 198.6 ± 1.12 µg/mL, respectively), and even higher against intracellular amastigotes of T. cruzi (IC₅₀: 911.6 ± 1.15 and 249.6 ± 1.18 µg/mL, respectively). Both A. rosaeodora essential oil and linalool did not exhibit a cytotoxic effect in BALB/c peritoneal macrophages, and both reduced nitrite levels in unstimulated cells revealing a potential effect in NO production. These data revealed the pharmacological potential of A. rosaeodora essential oil and linalool, encouraging further studies.

Pomological, Sensorial, Nutritional and Nutraceutical Profile of Seven Cultivars of Cherimoya (Annona cherimola Mill)

In this work, the food quality of four international (Campas, Chaffey, Fino de Jete and White) and three local (Daniela, Torre1 and Torre2) cultivars of Cherimoya (Annona cherimola Mill) was investigated. With this aim, pomological traits, sensorial attributes, physiochemical parameters (pH, total soluble content and total acidity), nutritional composition (macro- and micro-nutrients) and nutraceutical values (bioactive compounds, radical scavenging and antioxidant properties) were evaluated. Among the seven observed cultivars, Fino de Jete was identified as the best, not only for its commercial attributes such as pomological traits and physiochemical values, but also for its nutritional composition. On the other hand, Chaffey and Daniela were the cultivars with the highest content of polyphenols, proanthocyanidins, and with the strongest antioxidant capacity. Concerning the two local ecotypes, Torre1 and Torre2, they displayed a balanced nutritional profile that, if combined with their discrete nutraceutical, physicochemical and pomological values, may result in a reassessment of their commercial impact. In conclusion, our data provide interesting information about the pomological, nutritional, and nutraceutical properties of cherimoya fruits. Our results, in addition to promoting the commercial impact of local cultivars, may increase the use of individual cultivars in breeding programs.

Purification and characterisation of new laccase from Trametes polyzona WRF03

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Trametes polyzona WRF03 produced high yield of true laccase.

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Trametes polyzona WRF03 laccase was relatively pH and temperature stable.

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Fe²⁺, sodium azide and sodium cyanide greatly inhibited laccase activity.

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Trametes polyzona WRF03 laccase decolorised many classes of synthetic dyes.

The molecular screening for laccase specific gene sequences in Trametes polyzona WRF03 (TpWRF03) using designed oligonucleotide primers analogous to the conserved sequences on the copper-binding regions of known laccases showed positive amplification with an amplicon size corresponding to 1500 bp. The purified TpWRF03 laccase (TpL) is a monomer with a molecular weight corresponding to 66 kDa. The enzyme had an optimal pH of 4.5 and temperature of 55 °C. TpL was most stable within pH of 5.5–6.5 and at a temperature range of 40–50 °C. Sodium azide, sodium cyanide and Fe²⁺ greatly inhibited the enzyme activity. TpL showed more than 50 % decolourisation efficiency on coomassie brilliant blue (72.35 %) and malachite green (57.84 %) but displayed low decolourisation efficiency towards Azure B (1.78 %) and methylene blue (0.38 %). The results showed that TpWRF03 produces high-yield of true laccase with robust properties for biotechnological applications.

A novel profuse color card for convenient visual determination of iodide in human urine based on catalytic oxidation reaction

In this work, we reported a novel and convenient profuse color card for naked eye determination of iodide (I^-) in urine using chromogenic substrate 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). I^- catalyzed the oxidation of ABTS by peroxyacetic acid causing ABTS to yield cyan product ABTS⁺ with a new absorption peak at 730 nm. The addition of rose-red dye rhodamine B (RhB) changes the overall color of the solution from pink to purple and finally to blue, which makes the solution multicolor and easy to distinguish. A good linear relationship for I^- was obtained ranging from 10.0 to 500.0 μg/L with the detection limit of 9.2 μg/L. Importantly, the sensor can semi-quantitatively estimate the concentration of I^- in human urine with naked eye through the standard color card and assess the deficiency or excess of iodine in human body. The proposed profuse color card opens up a new colorimetric method for the rapid, simple and reliable determination of I^- in clinic, and has promising applications in developing assay kit for the clinical diagnosis of I^- in urine.

Alleviation of carbon tetrachloride-induced hepatocellular damage and oxidative stress in rats by Anabaena oryzae phycocyanin

Phycocyanin isolated from Anabaena biomass was in-vitro assayed for its antioxidant activity against DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS [2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)] free radical, revealing maximum activities amounting to 77 and 80% at 1,000 µg/ml and SC₅₀ values about 96 and 111 µg/ml, respectively. A biological experiment was conducted, involving 40 male Wistar Albino rats, divided into five groups. Group I received only the basal diet as a normal control, while groups II, III, IV, and V were administrated intraperitoneal (IP) injection of a single dose of CCl₄ (50% in corn oil) at 0.5 ml/kg body weight. Subsequently, groups II, III, IV, and V received phycocyanin at 0.0, 25, 50, and 100 mg/kg body weight/day. CCl₄ induced considerable increases (p < .05) in the levels of serum ALT, AST, urea and creatinine, total lipid, and triglycerides coupled with significant reductions (p < .05) in serum antioxidant enzymes and some liver histopathological deformations compared to the negative control (group 1). Administration of Anabaena oryzae phycocyanin can counteract these CCl₄ -induced changes. PRACTICAL APPLICATIONS: Phycocyanin isolated from Anabaena has beneficial effects such as the antioxidant, antibacterial, anticancer, and hepatoprotective effect. Phycocyanin may play a key role in alleviating oxidative stress, artificially induced by carbon tetrachloride in Albino rats, to ultimately determine its capacity to serve as a natural antioxidant for food and health applications.

Effect of Addition of Different Phenolic-Rich Extracts on Beer Flavour Stability

Flavour stability is a key factor in the beer production process. The stabilizing effect of six commercial phenolic-rich extracts was studied. The extracts were added to beer before bottling. Quality parameters (colour, turbidity, foam and dissolved oxygen content), antioxidant activity by 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), ferric reducing antioxidant power (FRAP), 1,1-diphenyl-2-picrylhydrazyl radical (DPPH), total polyphenols content, and sensorial analysis by a trained panel were performed over the course of storage. The beers were analyzed every 3 months for a total period of 6 months. Results indicated that all studied phenolic-rich extracts positively affected the beer flavour stability. In particular, the condensed tannins showed a significant protective effect. The condensed green tea tannins resulted as the most promising source of natural antioxidant able to prolong beer shelf-life and bring interesting organoleptic characteristics to beer. Also, grape seed tannins appeared suitable to boost flavour stability and improve organoleptic properties of beer.

Platinum(II) complex with 4-nitro-N-(pyridin-2-ylmethylidene)aniline: synthesis, characterization, crystal structure and antioxidant activity

A novel complex has been prepared using the (E)-4-nitro-N-(pyridin-2-ylmethylidene)aniline bidentate Schiff base ligand and PtCl₂, namely, dichlorido[(E)-4-nitro-N-(pyridin-2-ylmethylidene)aniline-κ²N,N']platinum(II) acetonitrile hemisolvate, [PtCl₂(C₁₂H₉N₃O₂)]·0.5CH₃CN, 1. According to the X-ray measurements of the crystal structure, the Pt^II ion adopts a PtCl₂N₂ square-planar coordination. The coordination of the Schiff base ligand to the Pt^II ion occurs in a cyclic bidentate fashion, as a result of which a five-membered metallacycle is formed. Furthermore, in the structure of 1, the neutral molecules form a one-dimensional chain structure through C-H...Cl and C-H...O hydrogen bonds. The characterization of the complex was performed via single-crystal X-ray diffraction, IR spectroscopy and elemental analysis, and the antioxidant activity of the complex was evaluated using spectrophotometry by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) method.

Transformation mechanisms of tetracycline by horseradish peroxidase with/without redox mediator ABTS for variable water chemistry

The threat of antibiotics in the environment causing antibiotics resistance is a global health concern. Enzymes catalyze pollutant transformations, and how commercially available enzymes like horseradish peroxidase (HRP), with or without a redox mediator, may be used to degrade antibiotics in water treatment is of great interest. This work demonstrates tetracycline transformation by HRP, and how it is significantly enhanced by free radicals created from the mediator 2,2-Azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). Water temperature and pH strongly influence the tetracycline removal rate due to their correlation with the enzyme activity, abundance and stability of ABTS^•+. Four transformation products were identified in the pure HRP system using a liquid chromatography tandem mass spectrometry hybrid quadrupole-orbitrap mass spectrometer system. Addition of 25 μmol L^-1 ABTS not only accelerated the degradation of tetracycline, but also expanded the range of degradation pathways. Potential tetracycline transformation pathways are proposed based on these observations, which include a range of mechanisms such as hydroxylation, demethylation, dehydration, decarbonylation and secondary alcohol oxidation. Despite of decreased efficiency, the HRP/ABTS system was able to degrade tetracycline in a domestic wastewater treatment plant effluent matrix, which demonstrates the potential of the system to be utilized in wastewater treatment.

Evaluation of Biological, Textural, and Physicochemical Parameters of Panela Cheese Added with Probiotics

Biological, physicochemical and textural parameters of a Panela cheese with and without probiotics (LSB-c and C-c) were analyzed during 15 days of storage at 4 °C. Changes in cohesiveness, hardness, springiness, and chewiness were measured by texture profile analysis. Additionally, moisture, pH, nitrogenous fractions (nitrogen soluble in pH 4.6, non-protein nitrogen, 70% ethanol-soluble nitrogen, and water-soluble extract) were evaluated. The peptide profile of nitrogenous fractions was also analyzed. Finally, biological activity was evaluated by ABTS (2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt) and DPPH (2,2-diphenyl-1-picrylhydrazyl), as well as the Inhibition of Angiotensin-Converting Enzyme. Analysis of variance showed significant differences for most of the evaluated parameters. By principal component analysis (PCA), two groups were separated, one corresponding to LSB-c and the other corresponding to C-c. The separation was given mostly by hardness, chewiness, and ABTS of all nitrogenous fractions. LSB-c showed higher biological activities than C-c.

ABTS radical-based single reagent assay for simultaneous determination of biologically important thiols and disulfides

Both the total amount of biothiols and thiol/disulfide ratio are wellness indicators of oxidative balance that play an important role in antioxidant defense system. Oxidized biothiols in disulfide form cannot be determined by conventional ABTS assay due to the biphasic kinetic pattern of the reaction between biothiols and ABTS radical cation (ABTS^•+), necessitating the initial reduction of disulfides to thiols prior to measurement. In this study, direct simultaneous determination of biothiols (RSH) and their disulfides (RSSR) by using a single reagent of ABTS^•+ was achieved without preliminary chemical reduction. Thus, conventional problems of preliminary operations arising from direct borohydride reduction of disulfides to thiols, followed by formaldehyde removal of borohydride excess and complications caused by formaldehyde-thiol reactions were effectively overcome with the use of a single reagent (ABTS^•+). Box-Behnken statistical experimental design was employed to specify the optimal incubation temperature and time as 60 °C and 60 min, respectively. The detection limits (LOD) of the proposed assay for biothiols were compared to those of the widely used DTNB (Ellman) reference assay known to be nonresponsive to disulfides, and were found to be much lower (4-70 times). The proposed biothiol assay was successfully applied to some pharmaceutical samples and synthetic serum without preliminary treatment, and the results were highly compatible with the HPLC findings. The proposed assay was demonstrated to have superior features such as simplicity, rapidity and higher sensitivity over the widely applied Ellman thiols assay.

Evaluation of Moroccan microalgae: Spirulina platensis as a potential source of natural antioxidants

Background Ethanolic, aqueous and lipidic extracts of Spirulina platensis were evaluated for their bioactive substances (polyphenols and fatty acids) and antioxidant activities using two different assays diphenyl-1-picrylhydrazyl (DPPH) and azino-bis (ethylbenzthiazoline-6- sulfonicacid (ABTS)). Methods The phenolic compounds amounts were determined by colorimetric assays and were analyzed by high-performance and liquid chromatography (HPLC) method. The identification of phenolic compounds in the extract was accomplished by comparison of their retention times with those of pure standards. The chemical composition of fatty acids in lipidic extract was determined by GC/FIDs and GC/MS method. Results The obtained results revealed that using DPPH, the ethanolic extract recorded the highest activity with (IC50=449 μg/mL ± 83). It was characterized with a high levels of phenolic and flavonoid content 0.33 ± 0.01 mg GAE/g dw and 0.21 ± 0.01 mg quercetin/g dw, respectively. The ethanolic extract showed the presence of caffeic acid, syringic acid, ferulic acid, p-coumaric acid, chlorogenic acid, kaempferol, quercetin and apigenin. Those entire phenolic compounds seem participle synergistically to the pronounced higher activity. To the best of our knowledge, the apigenin (4', 5, 7,-trihydroxyflavone), a natural compound which is famously known by its potent antiradical activity, was identified for the first time in Moroccan S. platensis only in the ethanolic extract. A high positive correlation (r=0.895) between the antioxidant activity and the chemical composition of ethanolic extract was observed. For ABTS, lipidic extract showed the highest activity with (IC50=740 μg/mL ± 12). A total of 15 fatty acids compounds, amounting 89.73% of the extract were identified. γ-linolenic acid (GLA) (39.02%) and α-linolenic acid (ALA) (13.85%) were the major component and contribute greatly to the antioxidant activity observed. The lipidic extract has a high content of unsaturated fatty acids (70.95%) which are often exhibited very high antioxidant activity since they have two or more double bonds and chain lengths. The aqueous extract either with DPPH or ABTS methods, recorded low antioxidant activity. Its correlation was r=0.499, lower than found in the ethanolic extract. Conclusions These results showed that Spirulina platensis could be considered as a valuable source of fatty acids and phenolics with potent antioxidant activity. It may be employed in the manufacture of pharmaceutical drugs as an alternative source of natural antioxidants.

Preparation and biological assessment of some aromatic hydrazones derived from hydrazides of phenolic acids and aromatic aldehydes

There has been substantial interest over the past many years in the design of novel chemical compounds containing the azomethine group (-NH-N=CH) and exhibiting various medicinal properties such as antibacterial, antiviral, antifungal, and anti-inflammatory activities. Herein, hydrazones were synthesized via the chemical reaction of substituted aromatic hydrazides with various aromatic aldehydes. The obtained products were confirmed using different physical and spectroscopic techniques, such as m.p., IR, 1H-NMR and 13C-NMR. The present study was designed to synthesize different aromatic hydrazones assembled by various combinations of aromatic hydrazides and aromatic benzaldehydes containing different substituents such as hydroxyl and polyhydroxyl groups as key structural features. Thus, incorporating such moieties and simultaneously creating highly-conjugated systems was expected to create novel species to mimic as much as possible natural phenolics, chalcones and stilbenes. Compounds of aromatic hydrazones synthesized in the present study were tested in vitro for their direct and indirect antioxidant activities using different methods such as DPPH, ABTS and FTC. The antioxidant activities of the new compounds ranged from very weak to very high activity. In addition, the inhibition of tyrosinase and cholinesterase by these compounds was tested. The new compounds containing two or three hydroxyl groups attached to aldehyde rings exhibited significantly greater inhibition effects on tyrosinase or cholinesterase activities in comparison to other compounds of the same series containing only one hydroxyl group.

In vitro evaluation of the bioaccessibility of antioxidative properties in commercially baby foods

Fruit-vegetable based products are essential for infants as they widely used the first complementary solid foods. This study aimed to investigate the physicochemical properties, the antioxidant capacities, total phenolic content, and bioaccessibility of 24 different commercially fruit-vegetable based complementary foods. To determination of bioaccessibility, samples were processed by an in vitro digestive enzymatic extraction that mimics the conditions in the gastrointestinal tract. Total polyphenol content was analyzed using Folin-Ciocalteu assay, and antioxidant capacities were assessed by CUPRAC and ABTS methods. The total phenol content of the samples ranges from 892.21 to 1729.13 mg GAE mg/100 g. While the antioxidant capacity of the samples averages 256.26 µmol TE mg/100 g according to the ABTS method, they were found 2417.79 µmol TE mg/100 g for CUPRAC method. Also, the bioaccessibility of total phenol content determined 62.72-98.48% of all samples. As a result, antioxidant properties and bioaccessibility of the samples were changed according to the sample content and chemical composition. The use of fruit or fruit juice in the preparation of commercial baby food has improved antioxidant capacity and bioaccessibility, thus increasing the beneficial health effect and nutraceutical properties of the baby meal.

Synthesis, in vitro safety and antioxidant activity of new pyrrole hydrazones

Six new N-pyrrolylhydrazide hydrazones were synthesized under micro synthesis conditions, assuring about 59-93 % yield, low harmful emissions and reagent economy. The structures of the new compounds were elucidated by melting points, TLC characteristics, IR, 1H and 13C NMR spectral data followed by MS data. The purity of the obtained compounds was proven by the corresponding elemental analyses. "Lipinski's rule of five" parameters were applied for preliminary evaluation of the pharmacokinetic properties of the target molecules. The initial in vitro safety screening for cytotoxicity (on HepG2 cells) and hemocompatibility (hemolysis assay) showed good safety of the new compounds, where ethyl 5-(4-bromophenyl)-1-(1-(2-(4-hydroxy-3-methoxybenzylidene)-hydrazineyl)-1-oxo-3-phenylpropan-2-yl)-2-methyl-1H-pyr-role-3-carboxylate (4d) and ethyl 5-(4-bromophenyl)-1-(1-(2-(2-hydroxybenzylidene)hydrazineyl)-1-oxo-3-phenylpropan--2-yl)-2-methyl-1H-pyrrole-3-carboxylate (4a) were the least toxic. The antioxidant activity in terms of radical scavenging activity (DPPH test) and reducing ability (ABTS) was also evaluated. The antioxidant protective potential of the compounds was next determined in different in vitro cellular-based models, revealing compounds 4d and 3 [ethyl 5-(4-bromophenyl)-1-(1-hydrazineyl-1-oxo-3-phenylpropan-2-yl)-2-methyl-1H-pyrrole-3-carboxylate] as the most promising compounds, with 4d having better safety profile.

Characterization of Novel Synthetic Polyphenols: Validation of Antioxidant and Vasculoprotective Activities

Antioxidant compounds, including polyphenols, have therapeutic effects because of their anti-inflammatory, antihypertensive, antithrombotic and antiproliferative properties. They play important roles in protecting the cardiovascular and neurological systems, by having preventive or protective effects against free radicals produced by either normal or pathological metabolism in such systems. For instance, resveratrol, a well-known potent antioxidant, has a counteracting effect on the excess of reactive oxygen species (ROS) and has a number of therapeutic benefits, like anti-inflammatory, anti-cancer and cardioprotective activities. Based on previous work from our group, and on the most frequent OH substitutions of natural polyphenols, we designed two series of synthetically accessible bis-polyhydroxyphenyl derivatives, separated by amide or urea linkers. These compounds exhibit high antioxidant ability (oxygen radical absorbance capacity (ORAC) assay) and interesting radical scavenging activity (RSA) values (2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and α,α-diphenyl-β-picrylhydrazyl (DPPH) tests). Some of the best polyphenols were evaluated in two biological systems, endothelial cells (in vitro) and whole aorta (ex vivo), highly susceptible for the deleterious effects of prooxidants under different inflammatory conditions, showing protection against oxidative stress induced by inflammatory stimuli relevant in cardiovascular diseases, i.e., Angiotensin II and IL-1β. Selected compounds also showed strong in vivo antioxidant properties when evaluated in the model organism Saccharomyces cerevisiae.

A Fungal Ascorbate Oxidase with Unexpected Laccase Activity

Ascorbate oxidases are an enzyme group that has not been explored to a large extent. So far, mainly ascorbate oxidases from plants and only a few from fungi have been described. Although ascorbate oxidases belong to the well-studied enzyme family of multi-copper oxidases, their function is still unclear. In this study, Af_AO1, an enzyme from the fungus Aspergillus flavus, was characterized. Sequence analyses and copper content determination demonstrated Af_AO1 to belong to the multi-copper oxidase family. Biochemical characterization and 3D-modeling revealed a similarity to ascorbate oxidases, but also to laccases. Af_AO1 had a 10-fold higher affinity to ascorbic acid (K_M = 0.16 ± 0.03 mM) than to ABTS (K_M = 1.89 ± 0.12 mM). Furthermore, the best fitting 3D-model was based on the ascorbate oxidase from Cucurbita pepo var. melopepo. The laccase-like activity of Af_AO1 on ABTS (V_max = 11.56 ± 0.15 µM/min/mg) was, however, not negligible. On the other hand, other typical laccase substrates, such as syringaldezine and guaiacol, were not oxidized by Af_AO1. According to the biochemical and structural characterization, Af_AO1 was classified as ascorbate oxidase with unusual, laccase-like activity.

Flavonoids with Glutathione Antioxidant Synergy: Influence of Free Radicals Inflow

This report explores the antioxidant interaction of combinations of flavonoid–glutathione with different ratios. Two different 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid radical (ABTS^•+)-based approaches were applied for the elucidation of the antioxidant capacity of the combinations. Despite using the same radical, the two approaches employ different free radical inflow systems: An instant, great excess of radicals in the end-point decolorization assay, and a steady inflow of radicals in the lag-time assay. As expected, the flavonoid–glutathione pairs showed contrasting results in these two approaches. All the examined combinations showed additive or light subadditive antioxidant capacity effects in the decolorization assay. This effect showed slight dilution dependence and did not change when the initial ABTS^•+ concentration was two times as high or low. However, in the lag-time assay, different types of interaction were detected, from subadditivity to considerable synergy. Taxifolin–glutathione combinations demonstrated the greatest synergy, at up to 112%; quercetin and rutin, in combination with glutathione, revealed moderate synergy in the 30–70% range; while morin–glutathione appeared to be additive or subadditive. In general, this study demonstrated that, on the one hand, the effect of flavonoid–glutathione combinations depends both on the flavonoid structure and molar ratio; on the other hand, the manifestation of the synergy of the combination strongly depends on the mode of inflow of the free radicals.

The Content of Phenolic Acids and Flavonols in the Leaves of Nine Varieties of Sweet Potatoes (Ipomoea batatas L.) Depending on Their Development, Grown in Central Europe

The aim of the study was the qualitative and quantitative analysis of the bioactive components present in the leaves of 9 sweet potato cultivars grown in the moderate climate in Poland, which were harvested at different growth stages according to the BBCH (Biologische Bundesanstalt, Bundessortenamt und Chemische Industrie) scale (14, 51, 89). It was found that sweet potato leaves contained 7 polyphenolic compounds, including 5 chlorogenic acids-neochlorogenic acid (5-CQA), chlorogenic acid (3-CQA), 4-cryptochlorogenic acid (4-CQA), 34-di-O-caffeoylqunic acid (3,4-CQA), 3,5-di-O-caffeoylqunic acid (3,5-CQA)-and 2 flavonoids, quercetin-3-O-galactoside (Q-3-GA) and quercetin-3-O-glucoside (Q-3-GL). Their content depended on the genotype of the examined cultivars and on the stage of leaf development. The mean content of the identified polyphenolic compounds in the examined cultivars ranged from 148.2 to 14.038.6 mg/100 g^-1 DM for the leaves harvested at growth stage 14 according to the BBCH scale. In the case of leaves harvested at BBCH stage 51, the concentration of polyphenolic compounds ranged from 144.76 to 5026.8 mg/100 g^-1 DM and at BBCH stage 89 from 4078.1 to 11.183.5 mg/100 g^-1 DM. The leaves of the Carmen Rubin cultivar collected at stage 14 contained the highest amount of polyphenolic compounds, while Okinava leaves had the highest amount of these compounds at stage 51. The highest content of polyphenolic compounds in leaves at BBCH growth stage 89 was found in the Radiosa variety. The highest concentration levels were found for 3-CQA at all stages of leaf development. Significant correlations between polyphenol content and antioxidant activity measured by 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and ferric reducing/antioxidant power (FRAP) were found. The results of this experiment revealed that the growth stages and genetic properties of cultivars have a very significant influence on the content of phenolic acids and flavonols in sweet potato leaves. The results are innovative and can have a practical application, as the knowledge of the content of the substances under study makes it possible to determine the optimal management practice of sweet potato leaf harvest in order to obtain more top-quality raw material.

New Advances in the Determination of Free and Bound Phenolic Compounds of Banana Passion Fruit Pulp (Passiflora tripartita, var. Mollissima (Kunth) L.H. Bailey) and Their In Vitro Antioxidant and Hypoglycemic Capacities

Banana passion fruit (Passiflora tripartite L.H. Bailey) is a lesser known species of the genus Passiflora. This fruit typically grows in the Andean region of Ecuador and it is locally known as tumbo, taxo or curuba. The juice of this fruit is highly appreciated in South America. Extracts of banana passion fruit were characterized for their content levels of free and bound phenolic compounds by high performance liquid chromatography coupled to high resolution mass spectrometry detector (HPLC-ESI-TOF-MS). A total of 82 polar compounds classified as phenolic acid derivatives, organic acids, benzophenones, flavan-3-ols, flavonols and flavones were detected in the extracts. The total phenolic content was 2356 mg 100 g^-1 dry matter, with the bound phenolic fraction representing 37.7% of total amounts. Flavan-3-ols, such as (epi)catechin, (epi)azfelechin and their derivatives, were the main phenolic compounds in the free phenolic fraction; however, phenolic acids represented the most abundant class of bound phenolic extracts. The antioxidant and hypoglycemic capacities reported for banana passion fruit were higher than for other fruits. To our knowledge, this is the first time that bound phenolic compounds have been described in banana passion fruit pulp.

Carotenoids and Chlorophylls as Antioxidants

Chlorophylls and carotenoids are natural pigments that are present in our daily diet, especially with the increasing tendency towards more natural and healthy behaviors among consumers. As disturbed antioxidant homeostasis capacities seem to be implicated in the progress of different pathologies, the antioxidant properties of both groups of lipophilic compounds have been studied. The objective of this review was to analyze the state-of-the-art advances in this field. We conducted a systematic bibliographic search (Web of Science™ and Scopus®), followed by a comprehensive and critical description of the results, with special emphasis on highly cited and more recently published research. In addition to an evaluative description of the methodologies, this review discussed different approaches used to obtain a physiological perspective, from in vitro studies to in vivo assays using oxidative biomarkers. From a chemical viewpoint, many studies have demonstrated how a pigment's structure influences its antioxidant response and the underlying mechanisms. The major outcome is that this knowledge is essential for interpreting new data in a metabolic networks context in the search for more direct applications to health. A promising era is coming where the term "antioxidant" is understood in terms of its broadest significance.

Black Soldier Fly (Hermetia Illucens) Larvae Protein Derivatives: Potential to Promote Animal Health

European legislation permits the inclusion of insect proteins in pet and aquaculture diets. Black soldier fly larvae (BSF) are one of the most actively produced species due to their low environmental impact and nutritional characteristics. BSF protein derivatives (proteins and protein hydrolysates) contain a substantial amount of low molecular weight peptides that are known to possess antioxidant potential. In this study, the in vitro antioxidant potential of commercial BSF proteins and protein hydrolysates was investigated for (1) radical scavenging activity, (2) myeloperoxidase activity modulation, and (3) neutrophil response modulation. Chickenmeal and fishmeal are commonly used in pet food and aquaculture formulations. Hence, both were used as industrial benchmarks during this study. The results indicate that fishmeal and chickenmeal are ineffective at suppressing the oxidative damage caused by neutrophil response and myeloperoxidase activity. Fishmeal and chickenmeal even exhibit pro-oxidant behavior in some of the models used during this study. On the other hand, it was found that BSF protein derivatives could be effective in protecting against the cellular damage resulting from neutrophil and myeloperoxidase activities. The outcomes of this study indicate that BSF protein derivatives could be potentially included in pet food and aquaculture feed formulations as health-promoting ingredients.

Phenolic profile, in vitro antimicrobial activity and antioxidant capacity of Vaccinium meridionale swartz pomace

Berries of Vaccinium meridionale Swartz contain a variety of phytochemicals, which are believed to account for their bioactive properties. The potential of Vaccinium meridionale Swartz pomace as a source of bioactive compounds was investigated. The dietary fiber (DF) content was assessed by the AOAC method, phenolic compounds were characterized and quantified via HPLC-PDA and UPLC-QTOF-MS. The in vitro antibacterial activity was tested against Gram-positive and Gram-negative bacteria. The antioxidant properties were assessed by the ORAC and the ABTS assays. The DF content was 52.4 ± 3.7%, phenolic compounds comprised anthocyanins (ACNs) (747.6 ± 167.5 mg cyanidin-3-glucoside/100 g FW), hydroxycinammic acids (HCAs) (229.2 ± 68.4 mg chlorogenic acid equivalents/100 g FW), flavonols (335.0 ± 139.5 rutin equivalents/100 g FW), and procyanidins (PACs) (140.9 ± 33.3 mg cocoa procyanidin equivalents/100 g FW). Staphylococcus aureus was more sensitive than E. coli. The ORAC value was 250.0 ± 32.0 μmol TE/g fresh weight (FW). Results suggest that the residue from V. meridionale S. can be utilized to obtain valuable nutraceuticals for the development of functional foods.

Study of Antioxidant Activity of some Medicinal Plants Having High Content of Caffeic Acid Derivatives

Recently, there has been increasing interest in medicinal plants, due to their content of health-promoting compounds, e.g., caffeic acids derivatives. Hence, the aim of this work was to study the antioxidant activity of extracts obtained from the following medicinal plants: caraway (Carum carvi L.), coltsfoot (Tussilago farfara L.), dandelion (Taraxacum officinale F.H.Wigg.), lovage (Levisticum officinale L.), tarragon (Artemisia dracunculus L.) and white mulberry (Morus alba L.), characterized by their high content of caffeic acid derivatives. The water-ethanolic extracts were characterized on average by about 9 times higher contents of caffeic acid derivatives level than water extracts. Both in water and water-ethanolic extracts, the dominant phenolic acid was 5-CQA (5-O-caffeoylquinic acid) and 3,4-diCQA (3,4-dicaffeoylquinic acid), then CCA-1 (chicoric acid isomer 1), which appeared only in water-ethanolic extracts. Extracts from dandelion contained compounds such as CTA (caftaric acid), CCA-1 (chicoric acid isomer 1) and CCA-2 (chicoric acid isomer 2), which were not detected in other plant extracts examined in this work. The water-ethanolic extracts from coltsfoot and tarragon were characterized by a high content of di-caffeoylquinic acids, especially 3,4-diCQA and 3,5-diCQA, respectively. It has been stated that there is a positive correlation between caffeic acid derivatives and antioxidant activity (radical cation scavenging activity (ABTS) and radical scavenging activity (DPPH)), especially in water-ethanolic extract of medicinal plants.

Anti-Hypochlorite, Antioxidant, and Catalytic Activity of Three Polyphenol-Rich Super-Foods Investigated with the Use of Coumarin-Based Sensors

The anti-hypochlorite activity of açaí (Euterpe oleracea Mart.), goji (Lycium barbarum L.) and schisandra (Schisandra chinensis) fruit extracts were assessed by determining the reactive chlorine species (RCS)-scavenging ability of these three "super-food" berries. In addition, the aqueous extracts obtained were employed as both the media and the catalyst in a green chemistry approach to the synthesis of a coumarin-based fluorescence turn-off sensor, which was then used for anti-hypochlorite activity testing. The aqueous extracts were also assessed for total phenolic content (TPC), using the Folin-Ciocalteu method, and the antioxidant activity using the ABTS^+• assay. Moreover, the main water-soluble polyphenolic constituents of the extracts were identified by the HPLC-PDA-ESI-MS technique. Among the extracts tested, açaí demonstrated the highest anti-hypochlorite and antioxidant activities, while the highest TPC value was found for the goji extract. All extracts demonstrated modest catalytic activity as Knoevenagel condensation catalysts.

α-VINIFERIN as a potential antidiabetic and antiplasmodial extracted from Dipterocarpus littoralis

Over the past few decades, complementary medicine therapy using medicinal plants have been developed in healthcare. Phytochemical studies about medicinal plants have been conducted to verify their potency as medicinal remedies in modern therapeutics. Dipterocarpus littoralis commonly known as Meranti Jawa in Indonesia is traditionally used to treat diseases such as diarrhea, diabetic and malaria. This study aimed to isolate bioactive compounds from D. littoralis using bioguided fractionation method. The bioactivity measured were antioxidant, antidiabetic, and antiplasmodial activity. Alpha-glucosidase and alpha-amylase assays were applied to estimate the in vitro antidiabetic activity of D. littoralis. The antioxidant activities were determined by using the free radical scavenging assays 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2-2″-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). Analysis of total flavonoid and phenolic contents were expressed as Quercetin Equivalent (QE) and Gallic Acid Equivalent (GAE), respectively. The in vitro antiplasmodial activity test of methanol extract of D. littoralis was also conducted against Plasmodium falciparum strain 3D7. Purification of the ethyl acetate fraction of the methanol extract of D. littoralis resulted in an oligostilbenes namely α-viniferin (1). The structure of the α-viniferin was characterized by comprehensive spectral analysis including IR, 1D and 2D NMR, and in comparison with the literature data. Compound 1 showed an alpha-glucosidase and alpha-amylase inhibitory activity with IC50 values of 256.17 and 212.79 μg/mL, respectively. The in vitro antiplasmodial activity test against Plasmodium falciparum strain 3D7 at a concentration of 100 μg/mL revealed a strong antiplasmodial inhibitory activity with IC50 value of 2.76 μg/mL. Our findings indicated that α-viniferin (1) which is isolated from D. littoralis extract could be regarded as potential antidiabetic and antiplasmodial resources in the future.

Heme•G-Quadruplex DNAzymes: Conditions for Maximizing Their Peroxidase Activity

Catalytic DNAs (DNAzymes) with peroxidase-like activity have great potential in bioanalytical chemistry [1], owing to numerous advantages that DNA enzymes offer over conventional protein enzymes, including structural simplicity, low cost, thermal stability, and straightforward handling and preparation. Maximizing the efficiency of the peroxidase activity of such DNAzymes is a subject in need of review. In this chapter, we discuss the optimal experimental conditions for the peroxidase activity of these DNAzymes and describe general procedures for their utilization.

Colorimetric-enzymatic determination of tyramine by generation of gold nanoparticles

In this paper, it has been demonstrated that Au(III) is able to act instead of O₂ in the oxidase enzymatic reaction, so that it becomes reduced to purple gold nanoparticles (AuNPs). The plasmon band (at 540 nm) can be used as the analytical signal. Tyramine has been determined using its enzymatic reaction with tyramine oxidase (TAO). The kinetic of the AuNP formation has been studied in the light of both the Avrami equation for crystallization and the Finke-Watsy mechanism for AuNP nucleation and growth. The effects of the Au(III), TAO and tyramine concentrations on the corresponding kinetic constants have been investigated. Working at room temperature, under optimal conditions (phosphate buffer pH 7.0, TAO 0.5 U.mL^-1 Au(III) 1 mM), the linear response ranges from 2.5 × 10^-5 M to 3.3 × 10^-4 M Tyramine (5.6% RSD) and the LOD is 2.9 × 10^-6 M. Under these conditions, the signal is measured after 30 min reaction (to obtain the highest sensitivity), but this time can be significantly reduced by increasing the temperature (the reaction is finished after 4 min when working at 50 °C). The method has been applied to tyramine determination in a cheese sample with good results. The new scheme proposed in this paper can be extended, in principle, to other enzymatic methods based on oxidase enzymes. Graphical abstractTyramine is determined by measuring the plasmon band of the gold nanoparticles formed during its enzymatic reaction with Tyramine oxidase. Moreover, a mathematical model has been developed to explain the formation of the gold nanoparticles during the reaction.

ABTS/PP Decolorization Assay of Antioxidant Capacity Reaction Pathways

The 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS^•+) radical cation-based assays are among the most abundant antioxidant capacity assays, together with the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-based assays according to the Scopus citation rates. The main objective of this review was to elucidate the reaction pathways that underlie the ABTS/potassium persulfate decolorization assay of antioxidant capacity. Comparative analysis of the literature data showed that there are two principal reaction pathways. Some antioxidants, at least of phenolic nature, can form coupling adducts with ABTS^•+, whereas others can undergo oxidation without coupling, thus the coupling is a specific reaction for certain antioxidants. These coupling adducts can undergo further oxidative degradation, leading to hydrazindyilidene-like and/or imine-like adducts with 3-ethyl-2-oxo-1,3-benzothiazoline-6-sulfonate and 3-ethyl-2-imino-1,3-benzothiazoline-6-sulfonate as marker compounds, respectively. The extent to which the coupling reaction contributes to the total antioxidant capacity, as well as the specificity and relevance of oxidation products, requires further in-depth elucidation. Undoubtedly, there are questions as to the overall application of this assay and this review adds to them, as specific reactions such as coupling might bias a comparison between antioxidants. Nevertheless, ABTS-based assays can still be recommended with certain reservations, particularly for tracking changes in the same antioxidant system during storage and processing.

Anti-inflammatory and anti-oxidative activities of lemon myrtle (Backhousia citriodora) leaf extract

In this present study, we examined the anti-inflammatory and anti-oxidative properties of alcoholic lemon myrtle extract (LME). The total polyphenol and flavonoid content of LME were determined as 118.77 and 14.53 mg/g extract, respectively. LME showed anti-oxidative properties, such as 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) and 2,2'-azino-bis(3-ethylbenz-thiazoline-6-sulfonic acid) (ABTS) radical scavenging activity. The anti-inflammatory activities of LME were investigated using the lipopolysaccharide-stimulated murine macrophage RAW 264.7 cells. Pretreatment with LME was performed at non-cytotoxic concentrations of 10-100 μg/mL. LME inhibited the production of inflammatory mediators such as nitric oxide (NO). Enzyme-linked immunosorbent assay and reverse-transcriptase polymerase chain reaction (RT-PCR) revealed that pretreatment with LME suppressed the protein expression and mRNA levels of pro-inflammatory cytokines such as interleukin IL-6, and tumor necrosis factor (TNF)-α in a concentration-dependent manner, respectively. These results suggest that LME could be used as a potential therapeutic agent having potent anti-inflammatory effects that could be used to treat inflammatory bowel disease.

Quantification of the Antioxidant Activity of Plant Extracts: Analysis of Sensitivity and Hierarchization Based on the Method Used

Plants have a large number of bioactive compounds with high antioxidant activity. Studies for the determination of the antioxidant activity of different plant species could contribute to revealing the value of these species as a source of new antioxidant compounds. There is a large variety of in vitro methods to quantify antioxidant activity, and it is important to select the proper method to determine which species have the highest antioxidant activity. The aim of this work was to verify whether different methods show the same sensitivity and/or capacity to discriminate the antioxidant activity of the extract of different plant species. To that end, we selected 12 species with different content of phenolic compounds. Their extracts were analyzed using the following methods: 2,2-di-phenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity assay, ferric reducing (FRAP) assay, Trolox equivalent antioxidant capacity (ABTS) assay, and reducing power (RP) assay. The four methods selected could quantify the antioxidant capacity of the 12 study species, although there were differences between them. The antioxidant activity values quantified through DPPH and RP were higher than the ones obtained by ABTS and FRAP, and these values varied among species. Thus, the hierarchization or categorization of these species was different depending on the method used. Another difference established between these methods was the sensitivity obtained with each of them. A cluster revealed that RP established the largest number of groups at the shortest distance from the root. Therefore, as it showed the best discrimination of differences and/or similarities between species, RP is considered in this study as the one with the highest sensitivity among the four studied methods. On the other hand, ABTS showed the lowest sensitivity. These results show the importance of selecting the proper antioxidant activity quantification method for establishing a ranking of species based on this parameter.

Alpha-Amylase and Alpha-Glucosidase Enzyme Inhibition and Antioxidant Potential of 3-Oxolupenal and Katononic Acid Isolated from Nuxia oppositifolia

Nuxia oppositifolia is traditionally used in diabetes treatment in many Arabian countries; however, scientific evidence is lacking. Hence, the present study explored the antidiabetic and antioxidant activities of the plant extracts and their purified compounds. The methanolic crude extract of N. oppositifolia was partitioned using a two-solvent system. The n-hexane fraction was purified by silica gel column chromatography to yield several compounds including katononic acid and 3-oxolupenal. Antidiabetic activities were assessed by α-amylase and α-glucosidase enzyme inhibition. Antioxidant capacities were examined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) scavenging assays. Further, the interaction between enzymes (α-amylase and α-glucosidase) and ligands (3-oxolupenal and katononic acid) was followed by fluorescence quenching and molecular docking studies. 3-oxolupenal and katononic acid showed IC₅₀ values of 46.2 μg/mL (101.6 µM) and 52.4 μg/mL (119.3 µM), respectively against the amylase inhibition. 3-oxolupenal (62.3 µg/mL or 141.9 μM) exhibited more potent inhibition against α-glucosidases compared to katononic acid (88.6 µg/mL or 194.8 μM). In terms of antioxidant activity, the relatively polar crude extract and n-butanol fraction showed the greatest DPPH and ABTS scavenging activity. However, the antioxidant activities of the purified compounds were in the low to moderate range. Molecular docking studies confirmed that 3-oxolupenal and katononic acid interacted strongly with the active site residues of both α-amylase and α-glucosidase. Fluorescence quenching results also suggest that 3-oxolupenal and katononic acid have a good affinity towards both α-amylase and α-glucosidase enzymes. This study provides preliminary data for the plant's use in the treatment of type 2 diabetes mellitus.

Optimisation of ultrasound-assisted extraction of phenolic antioxidants from Ilex guayusa Loes. leaves using response surface methodology

The present study carried out the optimisation of the total polyphenol content (TPC) extraction assisted by ultrasound in Ilex guayusa leaves applying response surface methodology (RSM). Also, the evaluation of the antioxidant activity of the extract obtained under the optimal extraction conditions was performed. The effect of the variables like, time of sonication, temperature, ethanol/water ratio and solid/liquid relationship and the interactions between them were analysed through the use of a factorial design 2ˆ4. The significant factors were considered for the optimisation, employing a Box-Behnken Design, and the TPC as response variables. It was found that a quadratic model was adequate, with an adjusted R² value of 0.9367. The optimal conditions proposed, by the response surface model were: an extraction temperature of 60 °C, sonication time of 29.9 min and ethanol/water ratio of 76.8/23.2. The optimised leaves extract of I. guayusa show a TPC of 3.46 (±0.17) g gallic acid equivalents/100 g d.w. Radical scavenger activity of the obtained extract at optimum conditions, was performed through the FRAP and ABTS methods, given as result: 0.080 mmol TROLOX equivalents/100 g d.w. and 40.71 μmol TROLOX equivalents/g d.w., respectively. Due to the present findings, I. guayusa extracts can be proposed as a promising component for functional beverages, cosmetic and pharmaceutical formulation.

Paper-based colorimetric biosensor of blood alcohol with in-situ headspace separation of ethanol from whole blood

This work presents a novel development that exploits the concept of in-situ gas-separation together with a specific enzymatic colorimetric detection to produce a portable biosensor called "Blood Alcohol Micro-pad" for direct quantitation of ethanol in whole blood. The thin square device (25 mm × 25 mm × 1.8 mm) comprises two layers of patterned filter paper held together with a double-sided mounting tape with an 8-mm circular hole (the headspace). In operation, the reagent is deposited on one layer and covered with sticky tape. Then 8 μL of a blood sample is dispensed onto the opposite layer and covered with sticky tape. Diffusion of ethanol across the 1.6 mm narrow headspace permits selective detection of ethanol by the enzymatic reagents deposited on the opposite layer. This reagent zone contains alcohol oxidase, horseradish peroxidase and 2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt, as the chromogenic reagent. The color intensity, measured from the recorded digital image, resulting from the enzymatic assay of ethanol, correlates with the concentration of blood alcohol. The results obtained with spiked mice and sheep blood samples, using an external calibration in the range of 1-120 mg dL^-1ethanol, gave recoveries of 93.2-104.4% (n = 12). The "Blood Alcohol Micro-pad" gave good precision with %RSD <1 (50 mg dL^-1 ethanol, n = 10) and limit of quantification (10SD of intercept/slope) of 11.56 mg dL^-1. The method was successfully validated against a headspace gas chromatography-mass spectrometric method. It has good potential for development as a simple and convenient blood alcohol sensor for on-site testing.

Chemical composition, anti-toxoplasma, cytotoxicity, antioxidant, and anti-inflammatory potentials of Cola gigantea seed oil

CONTEXT

Cola gigantea A. Chev. (Sterculiaceae) is an important medicinal tropical flora.

OBJECTIVE

The seed oil of C. gigantea, an underutilized tropical plant was investigated for its antioxidant, anti-inflammatory, anti-Toxoplasma, and cytotoxicity activities as well as the chemical composition.

MATERIALS AND METHODS

The physicochemical parameters of the seed oil obtained via Soxhlet extraction was determined while the fatty acid and non-fatty acid component were analyzed by gas chromatography-mass spectrometry. The antioxidant activity was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) assays (10-50 µg/mL) while the anti-inflammatory property was determined through Cell Membrane Stabilization assay. The anti-parasite and cytotoxicity activity were evaluated (0-1000 µg/mL) using Toxoplasma gondii and mammalian cell line assays, respectively.

RESULTS

The oil had fatty acids which ranged from C-12 to C-23 with linoleic (18:2) and palmitic acids (16:0) being dominant. The oil had 89.41% unsaturated fatty acids with sterolic acid, an uncommon acetylenic fatty acid reported for the first time. Non-fatty acids obtained include cholesterol (2.12%), campesterol (14.12%), stigmasterol (34.07%) and β-sitosterol (49.68%). The oil had a significantly (p < 0.05) low scavenging activity against DPPH radicals (IC₅₀ > 50 µg/mL) compared with ascorbic acid. In contrast, the oil showed better activity against ABTS radicals (IC₅₀ 44.19 ± 6.27 µg/mL) compared with ascorbic acid or quercetin. Furthermore, the oil showed anti-T. gondii and dose-dependent cytotoxicity in HFF cells with selectivity index (IC₅₀/EC₅₀ < 1).

DISCUSSION AND CONCLUSIONS

The antioxidant potential of the oil suggests that it may serve as a potential source for various preparations for pharmaceuticals and cosmeceuticals.

New enzymatic assays based on the combination of signal accumulation type of ion sensitive field effect transistor (SA-ISFET) with horseradish peroxidase

Peroxidase is widely used for the detection of secondary reactions during measurements of various enzymatic reactions, such as that of oxidase activity, or as an enzyme for immunoassay. Conventional methods utilizing the enzyme require expensive equipment such as a spectrophotometer to measure the absorption of light by the reaction product. Here, we describe a simple and cost-effective method for measuring enzymatic reactions using a signal accumulation type of ion sensitive field effect transistor (SA-ISFET) sensor capable of detecting the proton changes due to the enzymatic reaction. Using this detection principle, we constructed a detection system combining ABTS, an electron mediator, and a horseradish peroxidase activity detection system. As a result, we could quantitatively measure hydrogen peroxide with excellent reproducibility and linearity. As an application of this tool, we describe an oxidase-peroxidase reaction system for the measurement of glucose, sarcosine, uric acid and lactic acid. In addition, we describe an immunoassay system using a peroxidase-labeled antibody for detection of Escherichia coli. We also describe a prototype for a flow-type ISFET device for continuous and routine measurements.

Evaluation of the therapeutic activity of melatonin and resveratrol in Inflammatory Bowel Disease: A longitudinal PET/CT study in an animal model

Inflammatory Bowel Disease (IBD) is a group of chronic disorders of the gastrointestinal tract, which two main types are Crohn's disease and ulcerative colitis. Although conventional therapeutic strategies have demonstrated to be effective in the IBD treatment, it is necessary to incorporate novel therapeutic agents that target other mechanisms involved in the pathogenesis of the disease, such as oxidative stress. For this reason, the efficacy in vivo of two antioxidant compounds, melatonin and resveratrol, has been investigated in an animal model of TNBS (2, 4, 6-trinitrobenzenesulfonic acid) induced colitis. PET/CT (Positron emission tomography/Computer Tomography) scans were performed to assess disease activity and evaluate treatment response. SUV_max (Standardized Uptake Value) values, body weight changes and histological evaluation were used as inflammatory indices to measure the efficacy of both treatments. SUV_max values increased rapidly after induction of colitis, but after the beginning of the treatment (day 3) a statistically significant decrease was observed on days 7 and 10 in treated animals compared to the non-treated group. This remission of the disease was also confirmed by histological analysis of the colon tissue using the Nancy histological index (p value < 0.05 for differences between non-treated and both groups of treated animals). Moreover, statistical analysis showed a correlation (R² = 65.52%) between SUV_max values and weight changes throughout the treatment. Overall, this study demonstrates the potential of resveratrol, and melatonin in lower extent, as therapeutic agents in the IBD treatment.

Polyphenolic Characterization of Grape Skins and Seeds of Four Italian Red Cultivars at Harvest and after Fermentative Maceration

Agro-industry byproducts can still contain large amounts of phenolic compounds, and one of the richest sources are grape skins and seeds as grape pomace, both fermented (red winemaking) and unfermented (white winemaking). The residual polyphenolic content depends on various factors such as grape variety, vintage, and winemaking technique. In this work, four red grape varieties cultivated in northern Italy were studied: Albarossa, Barbera, Nebbiolo, and Uvalino. The work was aimed at studying the polyphenolic composition of skins and seeds from fresh grapes and from the corresponding pomace after fermentative maceration, to assess the actual importance of the varietal differences when processing winemaking byproducts for the extraction of phenolic compounds. The skin and seed extracts were prepared by solvent extraction with a 50% hydroalcoholic solution. The polyphenolic composition of all extracts was determined by spectrophotometry and high-performance liquid chromatography (HPLC); the content and the monomer composition of condensed tannins were determined by phloroglucinolysis; the antioxidant capacity was measured with the ABTS (2,2’-azinobis-(3-ethylbenzothiazoline-6- sulfonate)) method. The antioxidant capacity was higher for the seeds than for the skins, and it was positively correlated with the condensed tannins content. Significant differences in polyphenolic composition of fresh grape skins and seeds were observed between the different cultivars. In particular, Barbera and Albarossa skins were significantly distinguished from Nebbiolo and Uvalino skins for a higher content of anthocyanins and a lower content of vanillin-reactive flavans and condensed tannins; regarding seeds, Barbera and Albarossa had a lower content of vanillin-reactive flavans, proanthocyanidins, and condensed tannins than Nebbiolo and Uvalino. The winemaking process extracted the phenolic compounds to a different extent from skins and seeds, regardless of the cultivar. The differences between cultivars in the polyphenolic profile disappeared after fermentative maceration.

Multi-wavelength spectrophotometric determination of hydrogen peroxide in water by oxidative coloration of ABTS via Fenton reaction

In this study, a sensitive and low-cost multi-wavelength spectrophotometric method for the determination of hydrogen peroxide (H₂O₂) in water was established. The method was based on the oxidative coloration of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) via Fenton reaction, which resulted in the formation of green radical (ABTS^•+) with absorbance at four different wavelengths (i.e., 415 nm, 650 nm, 732 nm, and 820 nm). Under the optimized conditions (C_ABTS = 2.0 mM, C_Fe²⁺ = 1.0 mM, pH = 2.60 ± 0.02, and reaction time (t) = 1 min), the absorbance of the generated ABTS^•+ at 415 nm, 650 nm, 732 nm, and 820 nm were well linear with H₂O₂ concentrations in the range of 0-40 μM (R² > 0.999) and the sensitivities of the proposed Fenton-ABTS method were calculated as 4.19 × 10⁴ M^-1 cm^-1,1.73 × 10⁴ M^-1 cm^-1, 2.18 × 10⁴ M^-1 cm^-1, and 1.96 × 10⁴ M^-1 cm^-1, respectively. Meanwhile, the detection limits of the Fenton-ABTS method at 415 nm, 650 nm, 732 nm, and 820 nm were respectively calculated to be 0.18 μM, 0.12 μM, 0.10 μM, and 0.11 μM. The absorbance of the generated ABTS^•+ in ultrapure water, underground water, and reservoir water was quite stable within 30 min. Moreover, the proposed Fenton-ABTS method could be used for monitoring the variations of H₂O₂ concentration during the oxidative decolorization of RhB in alkali-activated H₂O₂ system.