Trolox Equivalent Antioxidant Capacity Values Research Articles

Exploring the Chemical Profile, In Vitro Antioxidant and Anti-Inflammatory Activities of Santolina rosmarinifolia Extracts.

In this study, the phytochemical composition, in vitro antioxidant, and anti-inflammatory effects of the aqueous and 60% ethanolic (EtOH) extracts of Santolina rosmarinifolia leaf, flower, and root were examined. The antioxidant activity of S. rosmarinifolia extracts was determined by 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assays. The total phenolic content (TPC) of the extracts was measured by the Folin-Ciocalteu assay. The anti-inflammatory effect of the extracts was monitored by the Griess assay. The chemical composition of S. rosmarinifolia extracts was analysed using the LC-MS technique. According to our findings, 60% EtOH leaf extracts showed the highest Trolox equivalent antioxidant capacity (TEAC) values in both ABTS (8.39 ± 0.43 µM) and DPPH (6.71 ± 0.03 µM) antioxidant activity assays. The TPC values of the samples were in good correspondence with the antioxidant activity measurements and showed the highest gallic acid equivalent value (130.17 ± 0.01 µg/mL) in 60% EtOH leaf extracts. In addition, the 60% EtOH extracts of the leaves were revealed to possess the highest anti-inflammatory effect. The LC-MS analysis of S. rosmarinifolia extracts proved the presence of ascorbic acid, catalpol, chrysin, epigallocatechin, geraniol, isoquercitrin, and theanine, among others, for the first time. However, additional studies are needed to investigate the direct relationship between the chemical composition and physiological effects of the herb. The 60% EtOH extracts of S. rosmarinifolia leaves are potential new sources of natural antioxidants and anti-inflammatory molecules in the production of novel nutraceutical products.

Colorimetric Sensing of Antioxidant Capacity via Auric Acid Reduction Coupled to ABTS Oxidation.

In this study, a simple and sensitive colorimetric assay has been developed for total antioxidant capacity measurement. The assay is based on the absorption measurement of the bluish-green oxidized product (ABTS·+) formed as a result of the oxidation reaction of the chromogenic reagent ABTS (2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) with gold(III). However, in the presence of antioxidants, the ABTS oxidation process is effectively suppressed due to the reduction of gold(III) ions to the zerovalent state forming gold nanoparticles (AuNPs). Relatively lighter colors and a significant decrease in absorbance are observed depending on the total antioxidant capacity. Taking advantage of this situation, qualitative and quantitative total antioxidant capacity (TAC) measurements, with the naked eye and UV-vis spectroscopy, respectively, could be successfully performed. The assay is named "auric reducing antioxidant capacity" (AuRAC) because the gold(III) ion-reducing ability of antioxidants is measured. The AuRAC assay was applied to dietary polyphenols, vitamin C, thiol-type antioxidants, and their synthetic mixtures. Trolox equivalent antioxidant capacity (TEAC) values obtained with the AuRAC assay were found to be compatible with those of the reference CUPRAC (cupric reducing antioxidant capacity) assay. The AuRAC assay was validated through linearity, additivity, precision, and recovery, demonstrating that the assay is reliable and robust. Compared to the simple TAC assays in the literature based on AuNP formation with subsequent surface plasmon resonance (SPR) absorbance measurement, this indirect assay has a smoother linear range starting from lower antioxidant concentrations. This method displays much higher molar absorption coefficients for antioxidant compounds than other conventional single electron transfer (SET) assays because 3-e- reduction of trivalent gold (i.e., Au(III) → Au(0)) produces three chromophore cation radicals (ABTS·+) of the assay reagent. The sensor has been successfully applied to complex matrices, such as tea infusions and pharmaceutical samples. The AuRAC assay stands out with its high molar absorptivity connected to enhanced sensitivity as well as its potential to convert into a paper-based colorimetric sensor.

Biocosmetics Made with Saccharina latissima Fractions from Sustainable Treatment: Physicochemical and Thermorheological Features.

This work deals with the formulation of natural cosmetics enriched with antioxidant fractions from the ultrasound treatment (US) of the brown seaweed Saccharina latissima. The challenge was the development of a cosmetic matrix without jeopardizing the thermorheological features of the creams, adding microparticles containing the antioxidant fractions using two different carriers, mannitol and alginate. The fundamental chemical characteristics of seaweed and the extracts obtained via sonication, as well as the antioxidant properties of the latter, were analyzed. The highest TEAC (Trolox equivalent antioxidant capacity) value was identified for the extracts subjected to the longest processing time using ultrasound-assisted extraction (240 min). A similar yield of microparticle formulation (around 60%) and load capacity (about 85%) were identified with mannitol and alginate as carriers. Color testing of the creams exhibited small total color differences. The rheological results indicated that the testing temperature, from 5 to 45 °C, notably influenced the apparent viscosity of the matrices. All creams were adequately fitted with the two parameters of the Ostwald-de Waele model, with the flow consistency index following an Arrhenius dependency with the testing temperature. Neither hysteresis nor water syneresis was observed in the proposed cosmetics during 6 months of cold storage at 4-6 °C.

Corylus avellana "Nocciola Piemonte": metabolomics focused on polar lipids and phenolic compounds in fresh and roasted hazelnuts.

The common hazel plant (Corylus avellana L., Betulaceae) is one of the most popular tree nuts widespread in Europe and Asia. In Italy, there are different cultivars among which the cultivar affording the valuable hazelnut "Tonda Gentile Trilobata," also known as "Tonda Gentile delle Langhe," covered by the Protected Geographical Indication (PGI) label "Nocciola Piemonte" (NP), known for its sweetness, cooked-bread aroma, and the low intensity of the burnt aroma. In order to obtain a detailed and in-depth characterization of the polar fraction of fresh (NPF) and roasted (NPR) kernels of NP the analysis of the n-butanol extracts by liquid chromatography coupled to electrospray ionization and high-resolution mass spectrometry (LC-ESI/HRMS) was carried out. Moreover, to evaluate the quantitative distribution of the most representative polar lipids in NPF and NPR, the analysis by liquid chromatography combined with tandem mass spectrometry (LC-MS/MS) was performed. To unambiguously identify the phenolic compounds highlighted by the LC-ESI/HRMS profiles, they were isolated from the n-butanol extract and characterized by Nuclear Magnetic Resonance (NMR) experiments. Finally, the ability of the isolated compounds to exert radical scavenging activity and to inhibit the lipid peroxidation induced by H2O2 or H2O2/Fe2+ was tested by Trolox Equivalent Antioxidant Capacity (TEAC) and thiobarbituric acid reactive substances (TBARS) assays, respectively. The LC-ESI/HRMS allowed to ascertain the presence of phenolic compounds and multiple classes of polar lipids including phospholipids, glycolipids, sphingolipids, and oxylipins. The quantitative analysis highlighted in NPR fraction a lipid content three times higher than in NPF, evidencing lyso-phospholipids and phospholipids as the most represented lipid classes in both NPF and NPR, together accounting for 94 and 97% of the considered lipids, respectively. Furthermore, phytochemical analysis permitted to identify flavonoid and diarylheptanoid derivatives. In particular, quercetin 3-O-β-D-galactopyranosyl-(1→2)-β-D-glucopyranoside and myricetin-3-O-α-L-rhamnopyranoside showed the highest antioxidant activity, exhibiting TEAC values similar to that of quercetin, used as reference compound (2.00 ± 0.03 and 2.06 ± 0.03 mM vs 2.03 ± 0.03 mM, respectively). Moreover, most of the tested compounds were found to reduce lipid peroxidation induced by H2O2 and H2O2/Fe2+ more than curcumin used as positive control, with myricetin-3-O-α-L-rhamnopyranoside determining 44.4 % and 34.1 % inhibition percentage, respectively.

Dioxomolybdenum(VI) complexes of 2-hydroxy-4-benzyloxybenzaldehyde thiosemicarbazones alkylated via N or S atoms. Synthesis, characterization, antioxidant and xanthine oxidase inhibition performance

Using the synthesis method, we produced a series of 2‑hydroxy-4-benzyloxybenzylidene N- or S-alkyl chains substituted thiosemicarbazones and their dioxomolybdenum(VI) complexes containing long alkyl chains (pentyl, hexyl, heptyl, and octyl). A series of dioxomolybdenum(VI) complexes with 2‑hydroxy-4-benzyloxybenzylidene thiosemicarbazones substituted by long alkyl chains, pentyl, hexyl, heptyl, and octyl, on the N- or S atoms were synthesized. Analytical and spectroscopic techniques were used to characterize the compounds. As a representative molecule, the molecular structure of complex I named cis-dioxo-(N1–2‑hydroxy-4-benzyloxybenzylidene-N4-pentylthiosemicarbazonato)-methanol-molybdenum(VI) was identified by single crystal X-ray diffraction. Using the method of cupric reducing antioxidant capacity, the ONN donor thiosemicarbazones (LV-LVIII) were found to have higher trolox equivalent antioxidant capacity values than those with ONS (LI-LIV). Furthermore, the inhibitory activities of xanthine oxidase and the scavenging effects of the compounds on the hydroxyl radical were examined. Complex VII was the most effective XO inhibitor with an IC50 value of 33.41 μM in similar to allopurinol as a potential XO inhibitor (IC50: 33.14 μM), and it can be used as XO inhibitor in treatment of XO-based disorders.

The Effects of Ripening Stage and Mode of Culture of Chemlali, Arbequina, and Koroneiki on the Capacities of Oils to Scavenge ABTS Free Radicals

This paper focuses on evaluating the antioxidant power of olive oil against the cation radical ABTS•+ according to cultivars (Chemlali, Arbequina and Koroneiki), culture modes (extensive and intensive), ripening stages (November and December corresponding stages), and study year (2017 and 2018). Radical percentage inhibition (PI), Trolox equivalent antioxidant capacity (TEAC), inhibitory concentration required to scavenge 50% of radicals (IC50), and principal component analysis (PCA) were determined. The oil of the Tunisian main cultivar, Chemlali, cultivated in extensive mode, has the best scavenging power with the lowest IC50 values of 9.3, 10.8, 9.65 and 10.4 µg/ml respectively in all the ripening stages. Also, at the lowest tested concentration of 20 µg/ml, this oil has the highest TEAC values, respectively 2.28 and 2.20 in November of 2017 and 2018. For the introduced cultivars, Koroneiki presents better performance than Arbequina, in intensive mode, with IC50 ranged from 9.6 to 13.8 against 12.40 to 22.35 for Arbequina. Furthermore, the principal component analysis proves that the oils of Chemlali in extensive mode and Koroneiki in intensive mode have the best scavenging capacity of ABTS•+. This study proves that the extensive mode is the best culture mode and the ripening stage of November is the best stage in order to get oils with the highest antioxidant capacity.

Effect of substitution of wheat flour with chickpea flour on their physico-chemical characteristics

PurposeThe major objective of this research work was to evaluate various physico-chemical characteristics, such as, chemical composition, antioxidant capacity, objective color and texture profile analysis (TPA) of the wheat flour/chickpea flour (CF) blends, so that nutritious baked products could be consumed by the type-2 diabetic persons.Design/methodology/approachWholegrain wheat flour (WGF) and white wheat flour (WWF) were substituted with CF at 0 to 40% levels. These wheat flour/CF blends were analyzed for proximate composition, the prepared dough and baked breads were tested for objective color, antioxidant capacity as trolox equivalent antioxidant capacity (TEAC), malondialdehyde (MDA) and total phenolic content (TPC) and TPA.FindingsWGF had the highest TEAC (117.42 mM/100g) value, followed by WWF (73.98 mM/100g) and CF (60.67 mM/100g). TEAC, MDA and TPC values varied significantly among all the three flour samples.Research limitations/implicationsInclusion of whole chickpea (without dehulling) flour in such type of blends would be another interesting investigation during the future research studies.Practical implicationsThese research findings have a great potential for the production of these baked products for human consumption on an industrial scale.Social implicationsProduction of breads using wheat flour and CF blends would benefits the consumers.Originality/valueProduction of Arabic and pan breads using wheat flour and CF blends would, therefore, combine the benefits of both the needed proteins of plant origin and the health-promoting bioactive compounds, in a most sustainable way for the consumers.

Chemometrics of the Composition and Antioxidant Capacity of Hyptis crenata Essential Oils from Brazil.

Hyptis crenata (Pohl) ex Benth is used in traditional medicine as an analgesic to treat general pain. Six Hyptis crenata samples (Hc-1 to Hc-6) were collected in Pará state, Brazil. The leaf essential oils were obtained by hydrodistillation, and GC-MS and GC-FID were used to analyze their chemical compositions. The antioxidant capacity was measured in vitro using DPPH and carotene/linoleic acid assays. Chemometrics analysis (PCA, HCA, and clustered heat map) were used to identify the sample relationships between those collected in this study and those from the literature (Hc-7 to Hc-16) samples. According to the main chemical constituents identified in the samples described in this work and the literature, the sixteen samples were classified into ten groups. Group I was characterized by 1,8-cineole (31.0%), α-pinene (13.6%), (E)-caryophyllene (7.8%), and β-pinene (7.6%); and Group IV was characterized by 1,8-cineole (17.4-23.5%), α-pinene (15.7-23.5%), β-pinene (10.5-13.4%), and limonene (8.5-9.7%). Both groups are described for the first time. The total antioxidant capacity was expressed in Trolox Equivalent Antioxidant Capacity values (TEAC): TEAC of Hc-5 (551.9 mg.TE/g) and Hc-6 (475.1 mg.TE/g). In the β-carotene/linoleic acid assay, the highest inhibition was from Hc-2 (40.0%), Hc-6 (39.0%), and Hc-3 (29.4%).

Sulfide-linked 3,4,5-trimethoxyphenyl-thiosemicarbazide/triazole hybrids: Synthesis, antioxidant, antiglycation, DNA cleavage and DNA molecular docking studies

Fourteen sulfide-linked 3,4,5-trimethoxyphenyl-thiosemicarbazide/triazole hybrid derivatives containing a variety of structural modifications on the thiosemicarbazide moiety were synthesized. Structure-activity correlations were investigated to determine the influence of structural variations on the antioxidant, antiglycation and DNA cleavage activities. Antioxidant activity was determined using the DPPH radical scavenging and CUPRAC assays. The majority of the derivatives displayed moderate to weak DPPH radical scavenging activity (IC50 = 20.96 to 106.7 μM) compared to ascorbic acid (IC50 = 13.72 μM), with derivatives having π-donating substituents being the most effective. A similar trend was observed for the CUPRAC assay. All derivatives containing electron-donating substituents were more effective than Trolox at reducing copper(II) ion, with Trolox Equivalent Antioxidant Capacity (TEAC) values ranging from 1.44 to 2.45. However, only the nitro derivative was found to be a promising antiglycation agent, inhibiting the formation of advanced glycation end products (AGEs) by 75 % compared to 27 % for the aminoguanidine control. In addition, the majority of the derivatives cleaved pBR322 plasmid DNA in the presence of copper(II) acetate. The interaction of the derivatives with DNA was confirmed by molecular docking studies, which revealed that all of the derivatives bind favorably in the minor groove of DNA.

Chemometric Screening of Oregano Essential Oil Composition and Properties for the Identification of Specific Markers for Geographical Differentiation of Cultivated Greek Oregano

The present study investigated the potential interconnection between the place of cultivation of Greek oregano samples and the composition and properties of their essential oils (EOs). In addition, it attempted to identify characteristic chemical features that could differentiate between geographical origins with the use of chemometric tools. To this end, a total of 142 samples of commercially available Greek oregano (Origanum vulgare ssp. hirtum) plants harvested during the calendar years 2017–2018 were obtained for this study. The samples came from five different geographical areas of Greece and represented twelve localities. After appropriate processing, the oregano samples were subjected to hydrodistillation (HD), and the resulting EOs were analyzed for their total phenolic content (TPC), antioxidant activity, and chemical composition. The acquired data were subjected to the chemometric methods of multivariate analysis of variance (MANOVA) and linear discriminant analysis (LDA) to investigate the potential of classifying the oregano samples in terms of geographical origin. In addition, stepwise LDA (SLDA) was used as a final step to narrow down the number of variables and identify those wielding the highest discriminatory power (marker compounds). Carvacrol was identified as the most abundant component in the majority of samples, with a content ranging from 28.74% to 68.79%, followed by thymol, with a content ranging from 7.39% to 35.22%. The TPC values, as well as the Trolox equivalent antioxidant capacity (TEAC) values, showed no significant variations among the samples, ranging from 74.49 ± 3.57 mg GAE/g EO to 89.03 ± 4.76 mg GAE/g EO, and from 306.83 ± 5.01 μmol TE/g EO to 461.32 ± 7.27 μmol TE/g EO, respectively. The application of the cross-validation method resulted in high correct classification rates in both geographical groups studied (93.3% and 82.7%, respectively), attesting to a strong correlation between location and oregano EO composition.

Combination of Machine Learning and Analytical Correlations for Establishing Quantitative Compliance between the Trolox Equivalent Antioxidant Capacity Values Obtained via Electron Paramagnetic Resonance and Ultraviolet-Visible Spectroscopies.

Recent interest in the antioxidant capacity of foods and beverages is based on the established medical knowledge that antioxidants play an essential role in counteracting the damaging effects of free radicals, preventing human neurodegenerative diseases, cardiovascular disorders, and even cancer. At the same time, there is no “the method" that uniquely defines the antioxidant capacity of substances; moreover, the question of interrelation between results obtained by different experimental techniques is still open. In this work, we consider the trolox equivalent antioxidant capacity (TEAC) values obtained by electron paramagnetic resonance (EPR) spectroscopy and ultraviolet–visible (UV–vis) spectroscopy using the classic objects for such studies as an example: red, rosé, and white wine samples. Based on entirely different physical principles, these two methods give values that are not so simply interrelated; this creates a demand for machine learning as a suitable tool for revealing quantitative correspondence between them. The consideration consists of an approximate correlation-based analytical model for the key argument (i.e., ) with subsequent adjustment by machine learning-based processing utilizing the CatBoost algorithm with the usage of auxiliary chemical data, such as the total phenolic content and color index, which cannot be accurately described by analytical expressions.

The Effects of Ripening Stage and Mode of Culture of Chemlali, Arbequina and Koroneiki on the Capacities of Oils to Scavenge ABTS Free Radicals

The aim of this study is to evaluate the antioxidant power of the olive oil against the cation radical ABTS•+, according to cultivars: Chemlali, Arbequina and Koroneiki; culture modes: extensive and intensive; ripening stages: November and December corresponding stages and study year: 2017 and 2018. Radical percentage inhibition (PI), Trolox equivalent antioxidant capacity (TEAC), inhibitory concentration required to scavenge 50% of radicals (IC50) and principal component analysis (ACP) were determined. The oil of the Tunisian main cultivar Chemlali, cultivated in extensive mode, has the best scavenging power with the lowest IC50 values of 9.3, 10.8, 9.65 and 10.4 µg/ml respectively in all the ripening stages. Also, at the lowest tested concentration of 20 µg/ml, this oil has the highest TEAC values, respectively 2.28 and 2.20 in November of 2017 and 2018. For the introduced cultivars, Koroneiki presents better performance than Arbequina, in intensive mode, with IC50 ranged from 9.6 to 13.8 against 12.40 to 22.35 for Arbequina. Furthermore, the principal component analysis proves that the oils of Chemlali in extensive mode and Koroneiki in intensive have the best scavenging capacity of ABTS•+. This study proves that the extensive mode is the best culture mode and the ripening stage of November is the best stage in order to get oils with a height antioxidant capacity.

A Generalized Method for Determining Free Soluble Phenolic Acid Composition and Antioxidant Capacity of Cereals and Legumes.

Phenolic acids are a class of organic compounds that bear both a phenolic group, and a carboxylic group. They are found in grains and concentrate in the bran of cereals or seed coat of legumes. They possess antioxidant properties that have generated much research interest in recent years, about their potential antioxidant protective health functions. This work presents a generalized method for the extraction of free soluble phenolic acids from whole grains and analysis of their antioxidant capacity. Five whole grain samples comprising two cereals (wheat and yellow corn) and three legumes (cowpea bean, kidney bean, and soybean), were used. The grains were milled into flour and their free soluble phenolic acids extracted using aqueous methanol. The compounds were then identified using a high-pressure liquid chromatograph (HPLC). The Folin-Ciocalteu method was used to determine their total phenolic content while their antioxidant capacities were determined using the DPPH radical scavenging capacity, Trolox equivalent antioxidant capacity (TEAC) and oxygen radical absorbance capacity (ORAC) assays. The phenolic acids identified included vanillic, caffeic, p-coumaric and ferulic acids. Vanillic acid was identified only in cowpea while caffeic acid was identified only in kidney bean. p-Coumaric acid was identified in yellow corn, cowpea, and soybean, while ferulic acid was identified in all the samples. Ferulic acid was the predominant phenolic acid identified. The total concentration of phenolic acids in the samples decreased in the following order: soybean > cowpea bean > yellow corn = kidney bean > wheat. The total antioxidant capacity (sum of values of DPPH, TEAC and ORAC assays) decreased as follows: soybean > kidney bean > yellow corn = cowpea bean > wheat. This study concluded that HPLC analysis as well as DPPH, TEAC, and ORAC assays provide useful information about the phenolic acid composition and antioxidant properties of whole grains.

Phytochemical content, especially spermidine derivatives, presenting antioxidant and antilipoxygenase activities in Thai bee pollens.

BackgroundBee pollen (BP) is full of useful nutrients and phytochemicals.Its chemical components and bioactivities depend mainly on the type of floral pollen.MethodsMonofloral BP from Camellia sinensis L., Mimosa diplotricha, Helianthus annuus L., Nelumbo nucifera, Xyris complanata, and Ageratum conyzoides were harvested. Crude extraction and partition were performed to yield solvent-partitioned extracts of each BP. Total phenolic content (TPC) was assayed by the Folin-Ciocalteu method, while the flavonoid content (FC) was measured by the aluminium chloride colorimetric method. Antioxidant capacity was measured by the (i) 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, (ii) 2,2’-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) scavenging activity and its Trolox equivalent antioxidant capacity (TEAC), and (iii) ferric reducing antioxidant power (FRAP). All samples were tested for lipoxygenase inhibitory (LOXI) activity. The most active sample was enriched by silica gel 60 column chromatography (SiG60-CC) and high performance liquid chromatography (HPLC), observing the chemical pattern of each fraction using thin layer chromatography. Chemical structure of the most active compound was analyzed by proton nuclear magnetic resonance and mass spectrometry.ResultsDichloromethane (DCM)-partitioned BP extracts of H. annuus L. and M. diplotricha (DCMMBP) showed a very high TPC, while DCMMBP had the highest FC. In addition, DCMMBP had the strongest DPPH and ABTS radical scavenging activities (as a TEAC value), as well as FRAP value. Also, DCMMBP (60 µg/mL) gave the highest LOXI activity (78.60 ± 2.81%). Hence, DCMMBP was chosen for further enrichment by SiG60-CC and HPLC. Following this, the most active fraction showed higher antioxidant andLOXI activities with an EC50 for DPPH and ABTS of 54.66 ± 3.45 µg/mL and 24.56 ± 2.99 µg/mL (with a TEAC value of 2,529.69 ± 142.16 µmole TE/g), respectively, and a FRAP value of 3,466.17 ± 81.30 µmole Fe2+/g and an IC50 for LOXI activity of 12.11 ± 0.36 µg/mL. Triferuloyl spermidines were revealed to be the likely main active components.ConclusionsTPC, FC, and spermidine derivatives played an important role in the antioxidant and antilipoxygenase activities in M. diplotricha bee pollen.

Convenient synthesis and evaluation of antioxidant property of functionalized spiro indolinone-dihydroquinazolinones

In the present study an efficient synthetic pathway has been developed for the library synthesis of diversely functionalized spiro indolinone-dihydroquinazolinones from easily available isatins and 2-aminobenzamides by acid catalyzed condensation at 70 °C in ethanol. The outcome of the ROS scavenging analysis over the synthesized spiro compounds displays significant variation in their respective antioxidant properties with the change of substituent at different positions. Noteworthy, the spiro compounds substituted with phenyl ring at nitrogen atom either in indolinone or dihydroquinazolinone moiety show a promising defensive capability towards OH (≈ 83% at 80 µM against control) and O2− (≈ 78% at 20 µM against epinephrine auto-oxidation). Almost every single spiro compound exhibits substantial reducing power, especially compounds containing dihydroquinazolinone moiety substituted with aromatic ring at amide nitrogen (N-3) exhibit remarkable reducing property. IC50 and TEAC (Trolox Equivalent Antioxidant Capacity) values reveal that the spiro compound substituted with phenyl ring to indolic nitrogen (N-1) possesses significant antioxidant potency (IC50 ≈ 22.67 µM) and substantial OH scavenging ability (TEAC ≈ 0.82) comparable to highly potent antioxidant Trolox.

Phytochemicals from fruit and vegetable waste generated in hotels: Optimization of recovery procedure and potential for value-addition

Fifteen star-category hotels in the National Capital Region of India were surveyed to assess the mixed fruit and vegetable waste generated. Based on the survey, a model mixed waste was prepared and used to identify the optimal procedure for recovery of bioactive phytochemicals and Trolox equivalent antioxidant capacity (TEAC) followed by preliminary identification of phytochemical constituents. The optimization procedure was done over (i) level I focusing on sample type (fresh, oven dried, vacuum dried), extraction technique (maceration, ultrasound assisted extraction), removal of interfering components by treatment with dichloromethane (DCM) and extraction in different solvents, and (ii) level II focusing on solvent concentration and extraction time, in both non DCM and DCM treated samples.The model mixed waste consisted of peels of pineapple, papaya, potato, pomegranate, apple, onion and citrus. The optimal conditions for recovery of phytochemicals and TEAC were non DCM treated vacuum dried samples subjected to ultrasonic assisted extraction for 60 min using ∼ 63% acetone. This resulted in recovery of appreciable amounts of total extractable phytochemicals consisting of polyphenols and flavonoids as the major components with relatively smaller amounts of flavones and flavanols. High TEAC values were obtained with both aqueous phase (ABTS) and organic phase (DPPH) assays. Preliminary investigation revealed the presence of various high-value compounds particularly gallic acid, ferulic acid, rutin and catechin in the phytochemicals extract. Consequently, there is significant potential to recover value-added phytochemicals from mixed fruit and vegetable waste from hotels contributing towards a circular bioeconomy.

Contribution of Hydrolysis and Drying Conditions to Whey Protein Hydrolysate Characteristics and In Vitro Antioxidative Properties.

During the generation of functional food ingredients by enzymatic hydrolysis, parameters such as choice of enzyme, reaction pH and the drying process employed may contribute to the physicochemical and bio-functional properties of the resultant protein hydrolysate ingredients. This study characterised the properties of spray- (SD) and freeze-dried (FD) whey protein hydrolysates (WPHs) generated using Alcalase® and Prolyve® under pH-stat and free-fall pH conditions. The enzyme preparation used affected the physicochemical and antioxidative properties but had no impact on powder composition, morphology or colour. SD resulted in spherical particles with higher moisture content (~6%) compared to the FD powders (~1%), which had a glass shard-like structure. The SD-WPHs exhibited higher antioxidative properties compared to the FD-WPHs, which may be linked to a higher proportion of peptides <1 kDa in the SD-WPHs. Furthermore, the SD- and FD-WPHs had similar peptide profiles, and no evidence of Maillard reaction product formation during the SD processing was evident. The most potent in vitro antioxidative WPH was generated using Alcalase® under free-fall pH conditions, followed by SD, which had oxygen radical absorbance capacity and Trolox equivalent (TE) antioxidant capacity values of 1132 and 686 µmol TE/g, respectively. These results demonstrate that both the hydrolysis and the drying process impact the biofunctional (antioxidant) activity of WPHs.

Poly(vinyl alcohol)-tannic Acid Cryogel Matrix as Antioxidant and Antibacterial Material.

The biocompatible, viscoelastic properties of poly(vinyl alcohol) (PVA) in combination with the antimicrobial and antioxidant natural polyphenolic, tannic acid (TA), and the natural flavonoid and antioxidant curcumin (Cur), were used in the preparation of PVA:TA and PVA:TA:Cur cryogel composites using cryotropic gelation to combine the individually beneficial properties. The effect of TA content on the antioxidant and antimicrobial activities of PVA:TA cryogel composites and the antioxidant activities of PVA:TA:Cur cryogel composites was determined using Trolox equivalent antioxidant capacity (TEAC) and total phenol content (TPC) assays, and were compared. The PVA:TA:Cur cryogel composite showed the highest antioxidant activity, with a TEAC value of 2.10 ± 0.24 and a TPC value of 293 ± 12.00. The antibacterial capacity of the PVA:TA and PVA:TA:Cur 1:1:0.1 cryogel composites was examined against two different species of bacteria, E. coli and S. aureus. It was found that the minimum inhibition concentration (MIC) value of the PVA:TA:Cur 1:1:0.1 cryogel composites varied between 5 and 10 mg/mL based on the type of microorganism, and the minimum bactericidal concentration (MBC) value was 20 mg/mL irrespective of the type of microorganism. Furthermore, the hemocompatibility of the PVA:TA cryogel composites was evaluated by examining their hemolytic and coagulation behaviors. PVA:TA 1:1 cryogels with a value of 95.7% revealed the highest blood clotting index value amongst all of the synthesized cryogels, signifying the potential for blood contacting applications. The release of TA and Cur from the cryogel composites was quantified at different pH conditions, i.e., 1.0, 7.4, and 9.0, and additionally in ethanol (EtOH) and an ethanol–water (EtOH:Wat) mixture. The solution released from the PVA:TA cryogels in PBS was tested for inhibition capability against α-glucosidase (E.C. 3.2.1.20). Concentration-dependent enzyme inhibition was observed, and 70 µL of 83 µg/mL PVA:TA (1:1) cryogel in PBS inhibited α-glucosidase enzyme solution of 0.03 unit/mL in 70 µL by 81.75 ± 0.96%.

Comparison of the antioxidant activities and major constituents of three Hypericum species (H. perforatum, H. scabrum and H. origanifolium) from Turkey

Total phenolic content, antioxidant activity, and the main constituents of three Hypericum species (H. perforatum, H. scabrum, and H. origanifolium) from Turkey had been investigated in this study. The quantification of main constituents (hypericin, and pseudohypericin) was performed by HPLC. The aerial parts of the plant extracts were screened in terms of their total phenolic content (TPC) and antioxidant activity tests including DPPH (2,2 diphenyl 1- picrylhdrazyl) radical scavenging activity, trolox equivalent antioxidant capacity (TEAC), ferric cyanide reducing (FRAP) antioxidant power assay, and total antioxidant activity by ferricthiocyanate (FTC). The highest TPC value (148.31 ± 4.57 mg GAE/g DW) was obtained for H. scabrum (HS) while H. perforatum (HP) extract had the highest hypericin (9.57 ± 0.07 µg/mL), and pseudohypericin (7.82 ± 0.05 µg/mL) amount. All Hypericum species demonstrated stronger DPPH activities than the standard compounds butylated hydroxytoluene (BHT) and ascorbic acid (AA) with the values of IC50 < 3.8 µg/mL. The highest trolox equivalent antioxidant capacity (TEAC) value (11.28 ± 0.28) was achieved with HO. Considerable values were obtained for HS (90.25 ± 0.05), HP (90.20 ± 0.07), and HO (88.42 ± 0.02) by total antioxidant determination using ferricthiocyanate (FTC) method with 2 days incubation. This study reveals that all Hypericum species are good sources of natural antioxidants with high TPC and major constituent contents.

Carbonic anhydrase inhibition and antioxidant activity of the axially naphthoxazin group substituted silicon phthalocyanines

Silicon phthalocyanines are an interesting subclass of phthalocyanines. They are abundant and have extremely low toxicity levels. The low solubility of silicon phthalocyanine is the major obstacle to its use in many different applications. Therefore, in a previous study, two axially substituted silicon phthalocyanines were synthesized to increase their solubility. In this study, these axially substituted silicon phthalocyanines were evaluated for carbonic anhydrase inhibition and antioxidant activities. The carbonic anhydrase (CA) inhibition potential of silicon phthalocyanines was evaluated by esterase activity. The antioxidant activity was tested by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and ferric ion (III) reducing/antioxidant power (FRAP) assays. The silicon phthalocyanines had significant CA inhibitory activity [50% inhibitory values (IC50): 495 ± 12.74 nM and 857 ± 13.03 nM for H4-Si and H3-Si, respectively]. According to the antioxidant studies, 50% scavenging concentration (SC50) values of DPPH• assay were 2.29 ± 0.06 µg/mL and 1.39 ± 0.43 µg/mL for H3-Si and H4-Si and Trolox Equivalent Antioxidant Capacity (TEAC) values of FRAP test were 259.33 ± 48.27 µM and 342.00 ± 44.40 for H3-Si µM and H4-Si, respectively. Consequently, silicon phthalocyanine compounds are considered to have great potential for their use in various fields such as food and medicine.