Reducing Antioxidant Capacity Research Articles

Phytochemicals, Antioxidant and Antimicrobial Potentials and LC-MS Analysis of Centaurea parviflora Desf. Extracts.

Centaurea parviflora (C. parviflora), belonging to the family Asteraceae, is an Algerian medicinal plant used in folk medicine to treat different diseases related to hyperglycemic and inflammatory disorders, as well as in food. The present study aimed to assess the total phenolic content, in vitro antioxidant and antimicrobial activity and phytochemical profile of the extracts of C. parviflora. The extraction of phenolic compounds from aerial parts was conducted using solvents of increasing polarity starting from methanol, resulting in crude extract (CE), to chloroform extract (CHE), ethyl acetate extract (EAE) and butanol extract (BUE). The total phenolic, flavonoid and flavonol contents of the extracts were determined using the Folin-Ciocalteu and AlCl3 methods, respectively. The antioxidant activity was measured with seven methods: 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, galvinoxyl free-radical-scavenging test, 2,2'-Azino-Bis(3-Ethylbenzothiazoline-6-Sulfonic Acid) (ABTS) assay, cupric reducing antioxidant capacity (CUPRAC), reducing power, Fe+2-phenanthroline reduction assay and superoxide-scavenging test. The disc-diffusion method aimed at testing the sensitivity of bacterial strains toward our extracts. A qualitative analysis with thin-layer chromatography of the methanolic extract was performed. Moreover, HPLC-DAD-MS was used to establish the phytochemical profile of the BUE. The BUE was found to contain high amounts of total phenolics (175.27 ± 2.79 µg GAE/mg E), flavonoids (59.89 ± 0.91 µg QE/mg E) and flavonols (47.30 ± 0.51 µg RE/mg E). Using TLC, different components such as flavonoids and polyphenols were noted. The highest radical-scavenging ability was recorded for the BUE against DPPH (IC50 = 59.38 ± 0.72 µg/mL), galvinoxyl (IC50 = 36.25 ± 0.42 µg/mL), ABTS (IC50 = 49.52 ± 1.54 µg/mL) and superoxide (IC50 = 13.61 ± 0.38 µg/mL). The BUE had the best reducing power according to the CUPRAC (A0.5 = 71.80 ± 1.22 μg/mL), phenanthroline test (A0.5 = 20.29 ± 1.16 μg/mL) and FRAP (A0.5 = 119.17 ± 0.29 μg/mL). The LC-MS analysis of BUE allowed us to identify eight compounds including six phenolic acids and two flavonoids: quinic acid, five chlorogenic acid derivatives, rutin and quercetin 3-o-glucoside. This preliminary investigation revealed that the extracts of C. parviflora have a good biopharmaceutical activity. The BUE possesses an interesting potential for pharmaceutical/nutraceutical applications.

Copper toxicity leads to accumulation of free amino acids and polyphenols in Phaeodactylum tricornutum diatoms

This work is focused on the effect of lethal and sub-lethal copper (Cu) concentrations on the free amino acid and polyphenol production by the marine diatom Phaeodactylum tricornutum (P. tricornutum) after 12, 18, and 21 days of exposure. The concentrations of 10 amino acids (arginine, aspartic acid, glutamic acid, histidine, lysine, methionine, proline, valine, isoleucine, and phenylalanine) and 10 polyphenols (gallic acid, protocatechuic acid, p-coumaric acid, ferulic acid, catechin, vanillic acid, epicatechin syringic acid, rutin, and gentisic acid) were measured by RP-HPLC. Under lethal doses of Cu, free amino acids reached levels significantly higher than those in the control cells (up to 21.9 times higher), where histidine and methionine showed the highest increases (up to 37.4 and 65.8 times higher, respectively). The total phenolic content also increased up to 11.3 and 5.59 times higher compared to the reference cells, showing gallic acid the highest increase (45.8 times greater). The antioxidant activities of cells exposed to Cu were also enhanced with increasing doses of Cu(II). They were evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging ability (RSA), cupric ion reducing antioxidant capacity (CUPRAC), and ferric reducing antioxidant power (FRAP) assays. Malonaldehyde (MDA) exhibited the same tendency: cells grown at the highest lethal Cu concentration yielded the highest MDA level. These findings reflect the involvement of amino acids and polyphenols in protective mechanisms to overcome the toxicity of copper in marine microalgae.Graphical

Ultrasound-Assisted Extraction of Total Phenolic Compounds and Antioxidant Activity Evaluation from Oregano (Origanum vulgare ssp. hirtum) Using Response Surface Methodology and Identification of Specific Phenolic Compounds with HPLC-PDA and Q-TOF-MS/MS.

Oregano is native to the Mediterranean region and it has been reported to contain several phenolic compounds particularly flavonoids that have been related with multiple bioactivities towards certain diseases. Oregano is cultivated in the island of Lemnos where the climate promotes its growth and thus it could be further used in promoting local economy. The aim of the present study was to establish a methodology for the extraction of total phenolic content along with the antioxidant capacity of oregano by using response surface methodology. A Box-Behnken design was applied to optimize the extraction conditions with regard to the extraction time, temperature, and solvent mixture with the use of ultrasound-assisted extraction. For the optimized extracts, identification of the most abundant flavonoids (luteolin, kaempferol, and apigenin) was performed with an analytical HPLC-PDA and UPLC-Q-TOF MS methodology. The predicted optimal conditions of the statistical model were identified, and the predicted values confirmed. The linear factors evaluated, temperature, time, and ethanol concentration, all showed significant effect (p < 0.05), and the regression coefficient (R2) presented a good correlation between predicted and experimental data. Actual values under optimum conditions were 362.1 ± 1.8 and 108.6 ± 0.9 mg/g dry oregano with regard to total phenolic content and antioxidant activity based on 2,2-Diphenyl-1-picrylhydrazyl (DPPH) assay, respectively. Additionally, further antioxidant activities by 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) (115.2 ± 1.2 mg/g dry oregano), Ferric Reducing Antioxidant Power (FRAP) (13.7 ± 0.8 mg/g dry oregano), and Cupric Reducing Antioxidant Capacity (CUPRAC) (1.2 ± 0.2 mg/g dry oregano) assays were performed for the optimized extract. The extract acquired under the optimum conditions contain an adequate quantity of phenolic compounds that could be used in the production of functional foods by food enrichment procedure.

Phenolic content and oxidative stability of chocolates produced with roasted and unroasted cocoa beans.

The aim of this study was to produce chocolate using roasted (RB) and unroasted cocoa beans (URB). The effect of roasting on the total phenolic content (TPC), antioxidant activity [2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity, ferric reducing antioxidant power (FRAP), and cupric ion reducing antioxidant capacity (CUPRAC) values], phenolic compounds, caffeine, oxidative stability [free fatty acid, peroxide, conjugated dienes, conjugated trienes, and thiobarbituric acid reactive substances (TBARS)], Fourier transform infrared (FTIR), and differential scanning colorimetry (DSC) analysis of both cocoa beans and chocolate samples were analyzed. According to the results, the TPC of URB (24.96 mg gallic acid equivalent (GAE)/g sample) was higher than roasted beans (21.32 mg GAE/g sample). Similar results were also seen in the TPC of chocolate samples. Although roasting did not affect the DPPH scavenging activity and caffeine content of cocoa beans, it decreased FRAP and CUPRAC values. (-)-Epicatechin and chlorogenic acid values were higher in unroasted bean and chocolate samples, but the amount of gallic acid increased with the roasting process. Free fatty acid, peroxide, conjugated dienes, conjugated trienes, and TBARS results of unroasted samples were lower than roasted ones, indicating better oxidative stability. The melting temperatures of cocoa beans changed with roasting while it was similar between chocolate samples. Composition of the beans and the chocolate samples were qualitatively determined with FTIR.

Phytochemical Analysis, Antioxidant, and Acetylcholinesterase Inhibitory Activity of Propolis from Northeastern Algeria

Propolis is a bee resinous substance consisting mainly of phenolic compounds having nutritional and therapeutic properties and formed by the mixing of the tree and plant secretions collected by honey bees. Herein, the present study was aimed to assess the antioxidant and anticholinesterase activity of ethanolic and acetone propolis extracts from two sampling sites in Souk Ahras city (northeast Algeria). The antioxidant activity of the extracts was determined by using the common antioxidant assays (1,1-diphenyl-2-picrylhydrazyl [DPPH], acide 2-2’-azino-bis (3-ethylbenzothiazoline-6-sulphonique) [ABTS], galvinoxyl radical [GOR], and cupric reducing antioxidant capacity [CUPRAC]), and the anticholinesterase activity was determined against acetylcholinesterase (AChE). Moreover, the total phenolic (TPC), flavonoid (TFC), and condensed tannins (CTC) contents were quantified. The propolis extracts showed a potent antioxidant/inhibitory activity which almost met that of synthetic antioxidants used as standards (butylated hydroxytoluene [BHT] and butylated hydroxyanisole [BHA]). In addition, the AChE activity was highly strongly inhibited in a dose-dependent manner by the propolis extracts. The propolis extracts proved their richness in bioactive molecules able to enhance various biological activities and processes.

Changes in biomarkers of redox status in serum and saliva of dogs with hypothyroidism

BackgroundHypothyroidism is the most common endocrine disorder diagnosed in dogs, leading to deleterious effects on a dog’s life quality. This study aims to evaluate changes in the redox status in canine hypothyroidism. For this purpose, a comprehensive panel of antioxidants and oxidants biomarkers were measured in serum and saliva of 23 dogs with hypothyroidism, 21 dogs with non-thyroidal illness, and 16 healthy dogs. Among the antioxidants, cupric reducing antioxidant capacity (CUPRAC), ferric reducing ability of plasma (FRAP), Trolox equivalent antioxidant capacity (TEAC), thiol, paraoxonase type 1 (PON-1) and glutathione peroxidase (GPx) were determined in serum and CUPRAC, ferric reducing ability of saliva (FRAS) and TEAC in saliva. The oxidant biomarkers included were total oxidant status (TOS), peroxide-activity (POX-Act), reactive oxygen-derived compounds (d-ROMs), advanced oxidation protein products (AOPP), and thiobarbituric acid reactive substances (TBARS) in serum and AOPP and TBARS in saliva.ResultsResults showed a significantly higher TEAC, PON-1, GPx, TOS, POX-Act, and d-ROMs, and a significantly lower AOPP in serum of dogs with hypothyroidism. Meanwhile, significantly lower FRAS and AOPP were observed in saliva of dogs with hypothyroidism. Once salivary concentrations were corrected based on their total protein concentrations, the only analyte showing significant changes was TBARS which was significantly higher in dogs with hypothyroidism.ConclusionsOur results show that dogs with hypothyroidism present alterations in the redox status in both serum and saliva. This study should be considered a preliminary study and further research addressing these changes should be made using larger populations.

Chemical constituents and antioxidant capacities of Asparagus africanus Lam.

Phytochemical study of the roots and aerial parts of Asparagus africanus Lam. have led to the identification of thirty-three specialized metabolites ( 1–33 ) including two undescribed steroidal saponins: (25 S )− 5 β -spirostan-3 β -ol-3- O - β - d -xylopyranosyl-(1→2)- β - d -glucopyranoside ( 4 ) and (25 S )− 5 β -spirostan-3 β -ol-3- O - β - d -glucopyranosyl-(1→6)-[ β - d -glucopyranosyl-(1→2)-] β - d -glucopyranoside ( 5 ) and eight undescribed norlignans Aspafricanol A-E ( 6–10 ), Aspafricanene ( 11 ) and Aspafricanone A-B ( 12–13 ). Their structures were characterized by using a combination of 1D, and 2 D NMR spectroscopic and mass spectrometry (HR-ESI-MS) analyses, as well as by comparison with literature values. The antioxidant potential of the phenolic constituents was evaluated by the 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl radical antioxidant capacity (HORAC) and cupric ion reducing antioxidant capacity (CUPRAC) methods. The results revealed higher antioxidant capacity for syringaresinol ( 21 ) in DPPH, HORAC and CUPRAC assays with IC 50 values of 15.9 ± 0.3, 86.0 ± 6.9 and 18.0 ± 1.7 µg/mL, respectively, compared to the positive controls (ascorbic acid, quercetin and Trolox). Additionally, compounds 7 , 9 and 28 showed similar or stronger activities than the positive controls in DPPH (IC 50 = 33.3 ± 5.7, 40.3 ± 0.6 and 46.7 ± 2.9 µg/mL, respectively), HORAC (IC 50 = 74.7 ± 4.6, 66.7 ± 5.8 and 99.3 ± 1.1 µg/mL, respectively), and CUPRAC assays (IC 50 = 128.7 ± 9.6, 123.3 ± 3.0 and 59.0 ± 1.7 µg/mL, respectively). • Thirty-three compounds were isolated from Asparagus africanus Lam. • Eight norlignans and two steroidal saponins are newly described. • Isolated phenolic constituents were evaluated for their antioxidant activities. • Four compounds showed good antioxidant activity similar to the standard used as control. • The greatest antioxidant activity was observed for syringaresnol.

Evaluation of the Antioxidant Capacity, Antimicrobial Effect, and In Vitro Digestion Process of Bioactive Compounds of Cherry Laurel Leaves Extracts

Cherry laurel is a less known fruit species with an astringent taste and is mostly consumed as fresh fruit only in the Black Sea and Marmara regions of Turkey. Cherry laurel (Laurocerasus officinalis Roemer) leaves can be prepared in different forms such as infusion by steeping the dried leaf in boiled water and as an extract for its further use as a food supplement or ingredient. In thisstudy, aqueous and ethanol extracts of cherry laurel leaves were prepared and examined in terms of total phenolic compound (TPC), total flavonoid compound (TFC), antioxidant capacities using 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and the copper reducing antioxidant capacity (CUPRAC) assays after submitting to in vitro digestion. Additionally, theantimicrobial potential of the leaves extract was evaluated. The TPC of ethanol and aqueous extracts were found at 17.62 and 0.83 mg gallic acid equivalent GAE.g-1 leaves and the TFC of ethanol and aqueous extracts were determined as 11.61 and 0.47 mg catechin equivalent CE.g-1 leaves, respectively. In terms of antioxidant activity results, ethanol and aqueous extracts had 41.11 and 0.77mg Trolox equivalent TE.g-1 leaves for the DPPH assay, and 67.05 and 1.63 mg TE.g-1 leaves for the CUPRAC assay. After gastric digestion post-gastric (PG), compared to the initial values significantly lower recovery of the TPC (11.2 and 41%) and TFC (5.8 and 14.9 %) was observed for ethanol and aqueous extracts. The recovery of TPC, TFC values after the intestinal fraction waslower compared to the PG fraction for ethanol extracts, whereas for aqueous extracts they were higher compared to the PG fraction. The highest inhibition zone was observed against Listeria monocytogenes and Aspergillus niger when 10% extract concentration was applied. The experimental data verified that these extracts displayed remarkable antioxidant and antimicrobial activities, and the extraction method was important in terms of the bioaccessibility of bioactive compounds.

Copper(II) complexes of fused ring selenosemicarbazones: Synthesis, structure elucidation, biological activity and molecular modeling

Reaction of copper(II) acetate with cyclohexanoneselenosemicarbazone (Hcysesc), 5-chloro isatinselenosemicarbazone (5-ClHIstsesc), 1-methyl isatinselenosemicarbazone (1-MeHIstsesc), 3-indole selenosemicarbazone (3-HInsesc), 3-acetylindole selenosemicarbazone (3-AcHInsesc and 2-naphthaldehyde selenosemicarbazone (2-Hnaphsesc) in 1:2 (M: L) molar ratio yielded complexes of stiochiometry, [Cu(L)2] 1–6 (L = cysesc 1; 5-ClIstsesc 2; 1-MeIstsesc 3; 3-Insesc 4; 3-AcInsesc 5; 2-naphsesc 6). All the complexes are characterized by IR, Mass and ESR spectroscopy. Two well defined g values (g‖ and g⊥) in ESR spectrum of complexes 1–4, 6 indicate axial symmetry, whereas symmetry around copper(II) metal in complex 5 is confirmed by three different g values (g1, 2.095; g2, 2.15; g3, 2.26), which supports rhombic distortion. The value of g‖ obtained is greater than g⊥, which is greater than ge, in 1–4, 6 is in well agreement in dx2-y2 ground term of square planar geometry. The value of empirical factor f for complexes 1–4, 6 lies in the range, 102–135 cm indicating a square planar geometry with small distortion, where as in complex 5 value (f = 146 cm) is in conformity of tetrahedral geometry with larger distortion. All the compounds (selenosemicabazones and their complexes) are tested for DPPH radical scavenging, ABTS radical scavenging, FRAP ferric reducing and CUPRAC cupric reducing antioxidant capacity assay and all the compounds have shown good antioxidant capacity in general. Best results are obtained for H1L with FRAP, 6.75 ± 0.01 μg TE/ml and CUPRAC, 9.52 ± 0.07 μg TE/ml. All the compounds are also tested for their anti-tubercular activity against M. tuberculosis H37RV strain ATCC27294. Ligands, H1L, H3L, H6L and complex 6 have shown highest anti-TB activity (MIC = 1.6 µg/ml) which is similar to the standard drugs (Isoniazid, Ethambutol). anti-TB activity of H2L and H5L (MIC = 12.5 µg/ml and 25 µg/ml) increased on complexation with copper(II) (MIC = 1.6 µg/ml, 2; 12.5 µg/ml, 6). Experimental results are supported by molecular modeling studies, where a considerable intermolecular interaction of these compounds with the active site of amino acid of enoyl reductase from M. tuberculosis has been observed with minimum binding energy −6.2, −7.3, −7.7, −7.4, −7.2, −8.7 Kcal/mol for H1L, H2L, H3L, H4L, H5L, and H6L and −7.2, −9.4, −8.6, −9.3, −9.9, and −10.6 Kcal/mol for copper complexes 1, 2, 3, 4, 5 and 6 exhibited respectively.

Marine halophyte derived polyphenols inhibit glioma cell growth through mitogen-activated protein kinase signaling pathway

Plants that are pharmacologically significant require intensive phytochemical characterization for bioactive profiling of the compounds, which has enabled their safe use in ayurvedic medicine. The present study is focused on the phytochemical analyses, quantitative estimation and profiling of secondary metabolites of leaf extract, as well as the antioxidant and cytotoxic activity of the potent halophytes such as Avicennia marina, Ceriops tagal, Ipomoea pes-caprae, and Sonneratia apetala. The in vitro antioxidant property was investigated using DPPH, ferric reducing antioxidant capacity (FRAP) assay. Bioactive compounds such as phenols, flavonoids, saponin and alkaloids were quantitatively estimated from the extracts of A.marina, C.tagal, I.pes-capra and S.apetala, which possessed higher phenol content than the other studied halophytes. The extracts at 200 µg/ml revealed higher antioxidant activity than the standard ascorbic acid and it functions as a powerful oxygen free radical scavenger with 77.37%, 75.35% and 72.84% for S.apetala, I.pes-caprae and C.tagal respectively and with least IC50 for I.pes-caprae (11.95 µg/ml) followed by C.tagal (49.94 µg/ml). Cell viability and anti-proliferative activity of different polyphenolic fractions of C.tagal (CT1 and CT2) and I.pes-caprae fraction (IP) against LN229, SNB19 revealed Ipomoea as the promising anti-cytotoxic fraction. IP-derived polyphenols was further subjected to apoptosis, migration assay, ROS and caspase − 3 and − 7 to elucidate its potentiality as a therapeutic drug. IP-polyphenols was found to have higher percentage of inhibition than the CT1 and CT2 polyphenols of C.tagal on comparison with TMZ. All the above-mentioned in-vitro analysis further validated the ability of IP-polyphenols inducing cell death via ROS-mediated caspase dependent pathway. Further, proteomic and phospho-proteomic analysis revealed the potential role of IP-polyphenols in the regulation of cell proliferation through MMK3, p53, p70 S6 kinase and RSK1 proteins involved in mitogen-activated protein kinase signaling pathway. Our analysis confirmed the promising role of I.pes-caprae derived polyphenols as an anti-metastatic compound against GBM cells.

Chemical composition, antioxidant, anticholinesterase, and alpha-glucosidase activity of Stevia rebaudiana Bertoni extracts cultivated in Algeria

Stevia rebaudiana Bertoni is an endemic species to Paraguay famous for its sweetening power and therapeutic potential for various diseases such as diabetes. The present work evaluates the chemical composition and antioxidant, anticholinesterase, and α-glucosidase activities of S. rebaudiana. The essential oil (EO) of dry Stevia leaves was analyzed by GC/MS and detected the presence of 33 components. Caryophyllene oxide (24.28%), spathulenol (12.31%) and nerolidol (11.8%), and manool oxide (7.36%) were identified as the major ones. The antioxidant activity was evaluated by four complementary methods: DPPH (2,2 diphenylpicrylhydrazyl, ABTS (2, 2’-azino-bis 3-ethylbenzthiazoline-6-sulfonic acid) free radicals scavenging, Cupric reducing antioxidant capacity (CUPRAC), and reducing power. The crude methanolic extract and its fractions showed a variable antioxidant activity and strongly correlated with the content of quantified bioactive compounds. The ethyl acetate fraction showed a very high antioxidant activity close to the tested standards, while EO was active only in the CUPRAC assy. The petrol ether and chloroform fractions showed the best butyrylcholinesterase (BChE) inhibitory activity with IC50 values: 123.7 ± 1.78 and 170.1 ± 0.78 μg/mL, respectively. On the other hand, EO and chloroform revealed a moderate inhibitory activity against acetylcholinesterase (AChE). The in vitro inhibitory effect of the extracts on α-glucosidase indicated that EO effectively inhibited the enzyme with an IC50: 74.9 ± 6.4 µg/mL, better than the standard acarbose. The EO of Stevia has a significant anti-diabetic potential.

Poly(ε‐caprolactone)/poly(m‐anthranilic acid) and poly(ε‐caprolactone)/poly(3,4‐ethylenedioxythiophene)‐poly(styrenesulfonate) electrospun nanofibers: Characterization, antioxidant, and electrochemical properties

AbstractConducting polymers are widely used in many biomedical applications, but their non‐degradability and non‐biocompatibility limit their widespread use in applications. For this reason, many studies have been carried out on the developing degradable, biocompatible, and electrically conductive polymers. In this study, mixtures of conductive polymers (poly(m‐antranilic acid) (P3ANA) and poly(3,4‐ethylenedioxythiophene)‐poly(styrenesulfonate) (PEDOT:PSS)) with biocompatible and biodegradable poly(ε‐caprolactone) (PCL) were prepared. Their nanofibers were obtained by electrospinning and their antioxidant properties were investigated by 2,2′‐azino‐bis‐3‐ethylbenzthiazoline‐6‐sulfonic acid (ABTS) and copper ion reducing antioxidant capacity (CUPRAC) assays. Electrochemical properties were also investigated by cyclic voltammetry and electrochemical impedance spectroscopy. The highest antioxidant activity was obtained from PCL/P3ANA3 electrospun nanofiber containing 10% (of PCL w/w) P3ANA with 93 and 614 μg TE/mg values for ABTS and CUPRAC assays, respectively. This nanofiber was found to be non‐toxic according to 2,5‐diphenyl‐2H‐tetrazolium bromide (MTT) analysis. PCL/PEDOT:PSS electrospun nanofiber has the highest maximum anodic current value of 0.08 mA. The maximum anodic current value of PCL/P3ANA3 nanofiber with the highest amount of P3ANA is also higher than other PCL/P3ANA nanofibers. These nanofibers were characterized by FT‐IR, UV–vis., XRD and TGA and their surface morphologies were examined by scanning electron microscopy (SEM).

Comparative Spectrophotometric and Chromatographic Assessment of Antioxidant Capacity in Different Marine Algae

ABSTRACT The objective of the current study was to analyze the vital phenolic compounds available in the marine macroalgae (mostly edible) collected from the southwest coast of Turkey, to compute their total antioxidant capacity (TAC) with the cupric ion reducing antioxidant capacity (CUPRAC) and 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) assays and to correspond their antioxidant power with high performance liquid chromatography (HPLC) findings. The predominant constitutive phloroglucinol unit of the phlorotannins was the main phenolic component in brown algae species. Among the tested species, those with the greatest phloroglucinol content found by HPLC were Cladostephus spongiosum f.verticillatum (31.62 ± 0.66 μmolg−1), Cystoseira barbata (13.34 ± 0.60 μmolg−1), and Dictyota dichotoma (11.23 ± 0.19 μmolg−1), respectively.

Effects of perinatal protein restriction on the oxidative balance in the hypothalamus of 60-day-old rats

ABSTRACT Objective Evaluate the effects of maternal low-protein diet on the oxidative stress in the hypothalamus of 60-day-old rats. Methods Male Wistar rats were divided into two experimental groups according to the mother’s diet during pregnancy and lactation; control group (NP:17% casein n=6) and a malnourished group (LP:8% casein n=6). At 60 days of life, the rats were sacrificed for the collection of the hypothalamus for further biochemical analysis. Results Our results showed an increase in oxidative stress in malnourished group, observed through an increase in carbonyl content (p=0.0357), a reduction in the activity of the glutathione-S-transferase enzyme (p=0.0257), and a reduction in the non-enzymatic antioxidant capacity evidenced by the decrease in the ratio reduced glutathione/oxidized glutathione (p=0.0406) and total thiol levels (p=0.0166). Conclusion A low-protein diet during pregnancy and lactation is closely associated with increased oxidative stress and reduced antioxidant capacity in the hypothalamus of sixty-day-old rats.

Comparative analysis of phenolic compositions and biological activities of three endemic Teucrium L. (Lamiaceae) species from Turkey.

This study investigates the chemical compositions and biological activities of the methanol extracts of three endemic Teucrium species (T. ekimii, T. pestalozzae and T. semrae) collected from Turkey. Total phenolic and flavonoid contents were assessed spectrophotometrically. The total phenolic and flavonoid content in the T. ekimii methanolic extract were importantly higher than other both extracts. The polyphenolic components of the extracts were identified by liquid chromatography. Seven phenolic compounds were identified namely catechin, rutin, luteolin, apigenin chlorogenic acid, sinapic acid and rosmarinic acid. Antioxidant activities were determined by five in vitro assays namely phosphomolybdenum assay, 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity, β-carotene bleaching assay, ferric ions reducing antioxidant power (FRAP) and cupric ions reducing antioxidant capacity (CUPRAC). The total antioxidant activity method exhibited that T. ekimii methanol extract exerted better antioxidant activity. The methanol extract of T. ekimii showed better antiradical scavenging activity as measured by DPPH assay. The antimicrobial capacities were determined by agar diffusion assay. Three endemic Teucrium species tested showed slight antibacterial activity only against Aeromonas hydrophila, Klebsiella pneumoniae and Streptococcus pneumoniae. The findings showed that three endemic Teucrium species may be utilized as natural sources of antioxidant and antimicrobial compounds in food and farmacy products.

Satureja hortensis L.’nin Fitokimyasallarının ve Antioksidan Kapasitesinin Belirlenmesi

Thyme is one of the spices that is widely consumed in the regions where it grows and is used in many dishes, especially soups, and gives a regional identity to the dish where it is used. In this study, the amount of phytochemicals and antioxidant capacity of the plant Satureja hortensis L. (süpürge kekiği, çibriska) which grows spontaneously and is used as a spice in meals in the Karakoçlar settlement area of Olur district of Erzurum province was investigated. The total amounts of phenolic and flavonoid substances were determined to be 40.85±0.85 mg GAE/g and 26.52±0.46 mg QE/g, respectively. In addition, the DPPH radical scavenging activity of the plant extract was calculated as 45.24 ±3.47 μg TE/mL and the IC50 value was calculated as 177.11±0.99 μg/mL. It was determined that the Cu2+ reducing antioxidant capacity of the S. hortensis plant extract was 2162.09±113.61 μg TE/mL and the Fe3+ reducing antioxidant capacity was 24.36±4.59 μg TE/mL. As a result, it was concluded that the S. hortensis plant, which is known with different names in different regions, has antioxidant potential and can be used as a natural antioxidant source in addition to its common use.

Determination of Total Antioxidant Capacities as Ascorbic Acid Equivalent of Tea Extract Samples from Different Brands Using Digital Image-Based Colorimetric Detection Method

In this study, the Digital Image-Based Colorimetric Detection Method developed by Bakırdere et al. was used to find the TAC (Total Antioxidant Capacity) value of tea samples from different brands. To determine the total amount of antioxidants in tea samples, the CUPRAC (cupric ion reducing antioxidant capacity) method, which is widely used in antioxidant determination, was combined with a digital image-based colorimetric detection system. To use in our study, a box with opaque wood material measuring 24 cm x 19 cm x 17 cm (width/length/depth) was designed and manufactured. In the analysis, the oxidation reaction between the chromogenic copper(II)-neocuproine (Cu(II)-Nc) reagent and antioxidants was utilized. The color change that occurs as a result of the oxidation was calculated using an application on smartphones. In our study, analyzes were performed on 4 different brand tea extract samples (tea A, tea B, tea C, tea D) to determine the total antioxidant capacity of ascorbic acid equivalent. The TAC values for ascorbic acid equivalent in tea extract samples were found as 380 ± 8 mg/L (tea A), 402 ± 4 mg/L (tea B), 213 ± 3 mg/L (tea C), 232 ± 4 mg/L (tea D) using the digital image-based colorimetric detection systems.

Kırgız Cumhuriyeti Issyk-Kul Bölgesinde Yetişen Yalanci İğde (Hippophae rhamnoides L.) Meyvelerinin Kimyasal Kompozisyonu ve Antioksidan Aktivitesi

The fruit of sea-buckthorn (Hippophae rhamnoides L.) is a rich source of nutrients and phytochemicals. This study determined the chemical composition and antioxidant activity of sea-buckthorn grown in Issyk-Kul region, Kyrgyz Republic, during maturation from August to November. Three different assays [ferric reducing antioxidant power (FRAP), DPPH radical scavenging activity (DPPH), and cupric ion reducing antioxidant capacity (CUPRAC)] were used to determine the antioxidant activity of sea-buckthorn fruits. Sea-buckthorn fruits had a sugar content of 6.57-8.08 g/100g, a dietary fiber content of 0.39-0.83 g/100g, an ash content of 0.49-0.99 g/100g, a lipid content of 6.56-6.98 g/100g and titratable acidity of 1.38-1.92%. The total phenolic content and total flavonoids of sea-buckthorn fruits were 408.52–886.48mg GAE/kg and 260.81-345.37mg CE/kg, respectively. Antioxidant activity values determined by FRAP, DPPH, and CUPRAC were 88.51-1041.22mg TE/kg, 1011.93-2673.22mg TE/kg, and 755.40-1232.55mg TE/kg, respectively. Total carotenoid content was 16.6-18.8 mg/kg. Results showed the relationship between the change in the color of sea-buckthorn berries and the chemical composition by the months of their ripening and the influence of weather conditions. All these results indicated that sea-buckthorn fruits could be beneficial for human nutrition while they might have a great potential to be used in a wide range of products to enrich their functional properties.

Kidney bean (Phaseolus vulgaris L.) milk substitute as a novel plant-based drink: Fatty acid profile, antioxidant activity, in-vitro phenolic bio-accessibility and sensory characteristics

Recently, plant-based milk alternatives have gained popularity due to healthy food trends, sustainability concerns, and environmental repercussions. The current study is unique for the investigation of in vitro phenolic bioaccessibility, fatty acid composition, and sensory evaluation of plant-based milk from two different local kidney bean varieties grown in Turkey, oval and cherry. Kidney bean milk had 1.92–2.32% protein, which was slightly greater than other commercial plant-based milk alternatives. The majority of the fatty acids in the samples were α-linolenic acid (25.66–27.78%) and palmitic acid (18.95–23.08%). The total antioxidant capacity bio-accessibility of kidney bean milk was 154%–295% by cupric reducing antioxidant capacity (CUPRAC) and 50%–186% by α, α-diphenyl-β-picrylhydrazyl (DPPH) free radical scavenging method while the total phenolic content bio-accessibility varied between 207%–266%. Overall acceptance of kidney bean milks varied between 2.9 and 4.1 out of 10. These findings presented that kidney bean milk is an alternative for the food industry with its rich bio-accessible antioxidant capacity and fatty acid profile although intense beany flavor detected during sensory analysis.

Tyrosinase Inhibitory and Antioxidant Activity of Paederia foetida L.

Paederia foetida L. is a tropical Asian plant containing bioactive compounds and often used as functional foods. The aim of this study was to determine the antioxidant capacity and inhibitory activity of P. foetida leaves extract on tyrosinase activity. In addition, the total phenolic content (TPC) and total flavonoid content (TFC) were determined. TPC and TFC was evaluated by the Folin-Ciocalteu and the aluminum chloride (AlCl3) colorimetric method, respectively. The antioxidant capacity was determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), and cupric reducing antioxidant capacity (CUPRAC) method. The antioxidant capacity was expressed as trolox equivalent antioxidant capacity (TEAC) dan ascorbic acid equivalent capacity (AAEC). The tyrosinase inhibitory activity was conducted by enzyme-linked immunosorbent assay (ELISA) using L-tyrosine as a substrate and measured at 490 nm by ELISA reader. TPC in the crude extract, fraction A, and fraction B was 173.18 ± 3.99, 553.95 ± 5.70 and 405.37 ± 33.90, respectively. TFC in the crude extract, fraction A, and fraction B was 12.79 ± 0,25, 143.16 ± 9.27, 143.50 ± 6.90, respectively. The best antioxidant capacity of the extract was shown in the DPPH method (15.71 ± 1.6 mg TEAC/g and 100.77 ± 8.5 mg AAEC/g). Meanwhile, fraction B showed the best antioxidant capacity by the FRAP (11.48 ± 1.5 TEAC/g and 8.39 ± 1.2 mg AAEC/g ) and CUPRAC (116.34 ± 1.9 mg TEAC/g and 66.11 ± 1.3 mg AAEC/g) methods. Tyrosinase inhibitory activity exhibited that the IC50 of fraction A and B was 13.67 μg/mL and 13.37 μg/mL, respectively.