Cupric Reducing Antioxidant Capacity Assay Research Articles

Indolyl imine compounds as multi-target agents; synthesis, antidiabetic, anticholinesterase, antioxidant activities and molecular modeling

A new range of indolyl imine system 3d-l has been successfully prepared from 4,6-dimethoxy-2,3-diphenyl-indole-7-carbaldehyde 2a and 4,6-dimethoxy-3-aryl-indole-7-carbaldehyde 2b-cvia Schiff base reaction. The structure of targeted compounds was confirmed by 1H and 13C NMR, FT-IR, mass spectrometry and single crystal X-ray diffraction techniques. The indolyl imine derivatives were also subjected to in vitro antidiabetic activities employing α-glucosidase and α-amylase enzymes. In terms of antidiabetic investigation, the α-glucosidase enzyme was found to be potential target due to the comparable inhibition concentrations with the standard acarbose and the compound 3e exhibited better potency than the standard. The anticholinesterase potency of the compounds was investigated towards the acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes. The compounds displayed moderate efficiency against the BChE enzyme with the best inhibition concentration of 30.48 μM by the compound 3h. The antioxidant properties of final compounds were determined by DPPH radical scavenging, ABTS Cation Radical Decolarization and CUPRAC Cupric Reducing Antioxidant Capacity assay methods. The ABTS cation scavenging assay provided the best responses for the compounds and the candidates 3k and 3l were determined as promising targets for the antioxidant activity. Plausible binding mode and interaction of ligands with the selected enzyme have been studied by molecular docking, supporting the experimental results. In silico ADME showed high drug likeness of the synthesized compounds.

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.

The Formulation of Dermato-Cosmetic Products Using Sanguisorba minor Scop. Extract with Powerful Antioxidant Capacities

There has been a significant increase in the use of botanical resources for the formulation of topical products designed for medicinal and cosmetic applications. Sanguisorba minor Scop., a botanical species, exhibits a variety of properties and has significant potential for applications in the field of cosmetics. The aim of this study was to formulate topical preparations, incorporating an extract derived from the plant S. minor Scop. comprising a combination of roots, leaves, and flowers. In the initial phase, a total of seven combinations were prepared using extracts derived from the roots, leaves, and flowers of S. minor Scop. (v/v/v). These combinations were subsequently subjected to evaluation for their antioxidant capacity using four distinct methods: 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), cupric reducing antioxidant capacity (CUPRAC), and Trolox equivalent antioxidant capacity (TEAC). An extract of plant organs in a ratio of 1:2:1 (v/v/v), which had a strong antioxidant capacity and demonstrated synergistic effects according to the DPPH, TEAC, and CUPRAC assays (with values of 1.58 ± 0.1, 1.18 ± 0.09, and 1.07 ± 0.07, respectively), was selected for inclusion in three dermato-cosmetic products (hydrogel, emulgel, and cream). All the prepared preparations were evaluated in terms of topical formulation attributes and organoleptic characteristics. The testing of dermato-cosmetic products included assessments of their topical formulation properties and organoleptic characteristics. The hydrogel, emulgel, and cream exhibited varying degrees of stretchability. In addition, a study was carried out to assess the in vitro release of polyphenols from the cosmetic formulations using a Franz diffusion cell system. The results showed that the emulgel containing the extract of S. minor Scop. had the highest and most significant release of polyphenols, with a release rate of 84.39 ± 1.01%. This was followed by the hydrogel and cream, which had release percentages of 80.52 ± 0.89 and 75.88 ± 0.88, respectively, over an 8 h period. Thus, for the first time in the literature, a topical cosmetic product with high antioxidant potential containing S. minor Scop. extract was developed and optimized.

A cupric reducing antioxidant capacity assay coupled to thin-layer chromatography

A cupric reducing antioxidant capacity assay coupled to thin-layer chromatography

Investigation of Chemical Components of Hexane Extract from the Stem of Arcangelisia flava via Phytochemical Test, GC-MS Analysis, FTIR Fingerprinting, and In Vitro Antioxidant Activity

Arcangelisia flava, also known as yellow root, is a woody vine indigenous to the Philippines. It has been established that it possesses medicinal properties, and several of its bioactive compounds have been identified. However, most of its possible bioactive nonpolar chemical compounds remain unidentified. In this study, the stem of A. flava was investigated for its chemical components, FTIR fingerprinting, and antioxidant activity. The stem of A. flava was chopped, ground, and then extracted with hexane per gram of A. flava. Thin-layer chromatography (TLC), phytochemical screening, GC-MS and FTIR analyses, cupric-reducing antioxidant capacity (CUPRAC), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assays were performed to evaluate the chemical components of A. flava hexane extract. TLC and phytochemical screening revealed the presence of some organic acids, triterpenes, sterols, essential oils, phenols, and flavonoids. Further characterization using GC-MS analysis revealed 64 chemical components classified into hydrocarbon, ketone, alcohol, aromatic compounds, aldehyde, ester, organosilicon, and other chemicals. The most abundant compound was hexacosane with a relative abundance of 43.17%. This was followed by tetracosane (8.85%), o-xylene (8.09%), and hexatriacontane (5.72%). The FTIR spectrum also revealed the presence of hydrocarbons such as alkanes and alkenes, confirming the 60% abundance of such class of compounds as revealed by GC-MS. Meanwhile, based on the CUPRAC and DPPH assay conducted, the hexane extract from the stem of A. flava had low antioxidant capacity. Based on the literature search, this is the first time the chemical composition of A. flava hexane extract has been evaluated and its chemical compounds identified. The findings presented in this paper should be taken into account for any future research on the species’ therapeutic properties.

Effects of extracting solvents on phytochemical, antioxidant, and antibacterial activity of some seaweeds from the Bay of Bengal offshore Island

Seaweed is a rich source of bioactive compounds. Therefore, searching of natural antioxidant and antibacterial agents as alternatives to a synthetic counterpart is of great interest. The effects of various extracting solvents (viz. methanol, ethanol, and acetone) on the phytochemical content, antioxidant, and antibacterial activity of seven seaweeds consisting of three brown seaweeds (Sargassum natans, Sargassum fluitans, Spatoglossum asperum), three red seaweeds (Hypnea pannosa, Hypnea musciformes, Porphyra linearis) and one green seaweed (Ulva lactuca) were evaluated. The antioxidant capacity of crude extracts was evaluated by total antioxidant activity (TAA), 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2, 2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and cupric reducing antioxidant capacity (CUPRAC) assays. Seaweed extracts were also tested against Staphylococcus aureus, Escherichia coli, Enterococcus faecalis, and Pseudomonas aeruginosa by agar well diffusion method. The total phenolic content (TPC) of seaweed extracts varied significantly (P < 0.05) ranging from 51.08 ± 0.72–74.62 ± 1.15 mg GAE/g. Methanolic extracts of S. natans showed significantly the highest TPC, total flavonoid content (79.22 ± 5.21 mg QE/g), and TAA (57.79 ± 4.35 mg AA/g) than other seaweed extracts. Methanolic extracts of S. natans also exhibited the highest DPPH and ABTS radical scavenging effects (EC50 = 0.74 ± 0.04 and 0.14 ± 0.01 mg/ml, respectively). While, methanolic and ethanolic extracts of S. natans showed significantly the highest effective concentration (ECA0.50) value (0.19 ± 0.02 mg/ml and 0.14 ± 0.02 mg/ml, respectively) of CUPRAC. Pearson's correlation test and principal component analysis showed the relation between TPC and various antioxidant activity assays of seaweed extracts. The seaweed methanolic extracts showed a comparatively higher zone of inhibition against all the bacterial strains than other solvent extracts. However, all the solvent extracts of U. lactuca were almost inactive against all the bacterial strains. The results of this study demonstrated that methanolic extracts of brown seaweeds showed comparatively better antioxidant and antibacterial activity, which could be used in the food and pharmaceutical applications.

Evaluation of antioxidant and antibacterial activities of some selected seaweeds from Saint Martin's Island of Bangladesh

The effects of extracting solvents on the antioxidant and antibacterial activity of crude extracts of six seaweeds were investigated. The antioxidant activity of seaweed crude extracts was evaluated by total antioxidant activity (TAA), 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)diammonium salt (ABTS), and cupric reducing antioxidant capacity (CUPRAC) assays. Acetone extract of B. wrightii showed significantly (P < 0.05) the highest total phenolic content (TPC) (71.09 mg GAE/g), while methanolic extract of Porphyra sp. had the highest total flavonoid content (75.61 mg QE/g). Methanolic extract of S. muticum showed significantly (P < 0.05) the highest TAA. Methanolic extract of P. tetrastromatica and S. muticum showed significantly (P < 0.05) the highest DPPH and ABTS radical scavenging effects, while acetone extract of B. wrightii showed significantly the highest ECA0.50 value (0.78 mg/ml) of CUPRAC activity. Pearson's correlation test and principal component analysis (PCA) confirmed the relationship between TPC and various antioxidant activity assays of seaweed extracts. Methanolic extracts of P. tetrastromatica, S. muticum and H. clathratus showed higher inhibitory zones against all the bacterial strains than other seaweed extracts. The results of this study indicated that brown seaweeds showed comparatively better antioxidant and antibacterial activity, which could be utilized in the food processing industries.

Fingerprinting FTIR-ATR Fraksi Kopi Robusta dan Arabika serta Korelasinya terhadap Aktivitas Antioksidan

Coffee has a positive effect on health due to its high content of antioxidant compounds. The potential antioxidant activity of coffee is strongly influenced by its chemical compound profile. This study aimed to analyze the effect of different solvents on the chemical metabolites profile, antioxidant activity, and to determine the relevant chemical functional groups which positively contribute to the coffee’s antioxidant activity. In this study, methanolic extract of coffee samples from robusta and arabica varieties were fractionated by liquid-liquid fractionation method using four solvents with different polarities. ABTS (2,2'-azinobis (3-ethylbenzothiazoline-6-sulphonic acid) and cupric reducing antioxidant capacity (CUPRAC) assays were applied to measure the antioxidant activity of the coffee fractions. Fourier Transform Infrared- Attenuated Total Reflectance (FTIR-ATR) based chemometric approach was used to identify the compound functional groups as the fingerprinting profile of the coffee fractions. Correlation between the FTIR-ATR fingerprinting with the antioxidant activity of the coffee fractions was studied using multivariate data analysis, i.e. Principal Component Analysis (PCA) and Orthogonal Partial Least Squares (OPLS). From this study, a reliable PCA model to evaluate the effect of different solvents to FTIR-ATR fingerprinting profile was produced. The correlation between FTIR-ATR fingerprinting profile with the antioxidant activity and the characterization of the chemical functional groups relevant to its antioxidant activity can be analyzed by a reliable OPLS model obtained. This study suggests that the highest antioxidant potential in coffee is found in ethyl acetate fraction both in robusta and arabica coffee samples, while the relevant chemical functional groups having positive correlation to antioxidant activity of coffee were phenol, carbonyl, cyclohexane, aromatic, amide, phenyl, amino, and alkene groups.

Analysis of Content Profiles, Antioxidant and Anticancer Properties in Endemic Hypericum salsolifolium

This study investigated the antioxidant and anticancer properties, phenolic compounds, and content profile of Hypericum salsolifolium plant extracts prepared with different solvents. The total phenolic content, total flavonoid content, and antioxidant potential [(2,2-diphenyl-1-picrylhydrazyl, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), ferric reducing antioxidant power, and cupric reducing antioxidant capacity assays] of Hypericum salsolifolium extracts obtained using solvents of different polarities (hexane, dichloromethane, methanol, and water) were measured using spectrophotometric methods. The contents of the extracts were analyzed using liquid chromatography–mass spectrometry and inductively coupled plasma—mass spectrometry methods. Anticancer detection was performed in human lung carcinoma cells using the 3-4,5-dimethylthiazol-2,5-diphenyltetrazolium bromide, annexin-V, and cell cycle assays, as well as fluorescence detection of acridine orange/ethidium bromide staining. The methanolic extract was determined to have higher activation values of total phenolics, total flavonoids, ferric reducing antioxidant power, and in the 2,2-diphenyl-1-picrylhydrazyl assay than the other extracts, and the aqueous extract had higher values in the 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) and cupric reducing antioxidant capacity assays. The methanolic extract showed a cytotoxic effect against human lung carcinoma cells (IC50: 141.96 µg/mL). It was found that Hypericum salsolifolium extract showed antioxidant and anticancer activities. It was concluded that this plant can be used as a nutritional supplement due to its glucose, phenolic compound, amino acid, and vitamin content.

Substituted 2,5 thiophene dicarboxaldehyde bisthiosemicarbazones and their copper(II) complexes: Synthesis, structure elucidation, HSA binding, biological activities and docking studies

Reaction of copper (II) acetate with 2,5 thiophenedicarboxaldehyde bisthiosemicarbazone (2,5 H2bttsc, 1H2L), 2,5 thiophenedicarboxaldehyde-N1-methyl bisthiosemicarbazone (2,5 H2bttsc-N1-Me, 2H2L) and 2,5 thiophenedicarboxaldehyde -N1-phenyl bisthiosemicarbazone (2,5 H2bttsc-N1-Ph, 3H2L) in 1:1 (M:L) molar ratio yielded complexes of stoichiometry, [Cu(L)] 1-3 (1L, 1; 2L 2; 3L 3). All the complexes are characterized using elemental analysis FTIR, Mass and ESR spectroscopy. The two distinct g values, g‖ = 2.40 (1), 2.15 (2), 2.20 (3) and g⊥ = 2.08 (1), 2.07 (2), 2.12 (3) indicate axial symmetry for the complexes. The greater g‖ value than g⊥, confirms the presence of free electrons in dx2-y2 ground term in square planar geometry. The ligands (1H2L - 3H2L) and their complexes (1–3) were tested for DPPH radical scavenging, ABTS radical scavenging, FRAP ferric reducing, and CUPRAC cupric reducing antioxidant capacity assays. In general, all the ligands and their metal complexes exhibited moderate antioxidant potential, however 3H2L has shown best Cu2+ reducing activity (7.34 μg TE/ml) and ABTS radicals scavenging activity (IC50, 16.95) amongst all. Ligands (1H2L - 3H2L) and their complexes (1–3) were also evaluated for anti-tuberculosis activity against M. tuberculosis H37RV strain. It has been observed that with the increase of hydrophobicity of ligand due to substituent present at N1 atom, anti-TB activity increased (H, MIC = 6.25 µg/ml < Me, MIC = 3.12 µg/ml < Ph, MIC = 1.6 µg/ml). Molecular modeling studies have shown considerable intermolecular interaction of these compounds with minimum binding energy −5.8 (1H2L), −5.8 (2H2L), −9.6 (3H2L), −6.9 (1), −6.6 (2) and −9.6 (3) Kcal/ mol, which also supports the experimental data. Pharmacokinetics (effective transport of molecule to their target sites) was studied using drug-protein binding study of molecules with human serum albumin (HSA) was performed using UV–vis and fluorescence spectroscopy. The ligand 2H2L and complex 2 showed strong binding interactions with HSA having binding constant values of 4.24 × 105 M−1 and 4.92 × 105 M−1 respectively.

Antioxidant and Anticholinesterase Potentials of Novel 4,6-Dimethoxyindole based Unsymmetrical Azines: Synthesis, Molecular Modeling, In Silico ADME Prediction and Biological Evaluations

Chemically and biologically important -C = N-N = C- diimine linkage was used to build unsymmetrical azine systems with indole heterocyclic backbone and substituted aromatic carbaldehydes. Ten novel compounds 7a-j were synthesized by the Schiff base reaction of 4,6-dimethoxyindole-7-hydrazone 5 and a range of substituted carbaldehydes 6a-j with high yields and purities. The biological study was directed to identify the antioxidant potentials due to the expected electronic delocalization capability of designated linkage which is important for possible hydrogen or electron donation. The three different assays, namely DPPH free radical scavenging, ABTS cationic radical decolarization and CUPRAC (cupric reducing antioxidant capacity) were employed to detect the antioxidant properties. The antioxidant potentials were found to be moderate for ABTS and CUPRAC assays and the compound 7j was the most potent candidate for all the antioxidant assays. More importantly, the anticholinesterase properties were investigated by acetylcholinesterase (ACh) and butyrylcholinesterase (BCh) enzyme inhibition assays. The molecular docking studies were also carried out to determine the possible poses of ligands 7a-j in binding sites of enzymes and ligand-residue interactions. The synthesized compounds were found to be more effective for the anticholinesterase activity with three promising candidates 7d, 7h and 7j in the case of BChE inhibitions. The compound 7h was determined as the best candidate with the comparable IC50 values for AChE and better inhibition potency for BChE with 7j. A range of hydrophobic and hydrophilic interactions were detected for the designated compound 7h and 7j through different amino acid residues and the computational results were found to be compatible with the biological counterparts.

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.

Comparing the extraction methods, chemical composition, phenolic contents and antioxidant activity of edible oils from Cannabis sativa and Silybum marianu seeds

In the study the cold-pressed, natural (unfiltered, unrefined) vegetable oils: hemp and milk thistle seed oils were tested for their chemical composition and antioxidant properties. The physico-chemical parameters, content of saturated and unsaturated fatty acids were determined. Solid phase extraction and simple extraction with the use of methanol, ethanol, 80% methanol, 80% ethanol were used to obtain the extracts for the analysis of antioxidant activity and phenolic compounds in oils. The composition of phenolic compounds was studied by means of high-performance liquid chromatography (HPLC–DAD) and spectrophotometric test with the Folin-Ciocalteu reagent. The antioxidant property of extracts was established by means of the following methods: with the DPPH• (2,2-diphenyl-1-picrylhydrazyl) radical, ABTS•+ (2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) cation radical, FRAP (ferric ion reducing antioxidant parameter) and CUPRAC (cupric-reducing antioxidant capacity). Moreover the influence of chlorogenic acid on the inhibition of lipid peroxidation process in the hemp and milk thistle seed oils was also investigated. The tested oils showed different antioxidant properties which was related to the their different chemical composition. The main phenolic compounds present in hemp seed oil were vanillic, ferulic and p-coumaric acids, (-)epicatechin, catechin, kaempferol and procyanidin B2, whereas in milk thistle seed oil—catechins, procyanidin B2, procyanidin C1, p-coumaric acid, phloridzin, quercetin, protocatechuic acid, kaempferol, and syringic acid. The methanolic extracts of hemp and milk thistle seed oils showed the highest antiradical activity, whereas the ethanolic extracts revealed the best reducing properties. The obtained antioxidant parameters for hemp seed oil were: the IC50 = 3.433 ± 0.017 v/v (DPPH test), the percent of ABTS•+ inhibition = 93.301 ± 1.099%, FRAP value = 1063.883 ± 39.225 µmol Fe2+, CUPRAC value = 420.471 ± 1.765 µmol of Trolox. Whereas the antioxidant parameters for milk thistle seed oil were: the IC50 = 5.280 ± 0.584 v/v (DPPH test), 79.59 ± 3.763% (ABTS test), 2891.08 ± 270.044 µmol Fe2+ (FRAP test), 255.48 ± 26.169 µmol of Trolox (CUPRAC assay). Chlorogenic acid effectively inhibited the lipid peroxidation process in hemp and milk thistle seed oils.

Hybridization of Aminoadamantanes with Cinnamic Acid Analogues and Elucidation of Their Antioxidant Profile

A series of seventeen cinnamic acid hybrids (4ai–ci) were obtained through an amidation of aminoadamantanes (amantadine, rimantadine, and memantine) with mixed anhydride generated from different substituted cinnamic acid and ethyl chloroformate. 1H NMR, 13C NMR, IR, and HRMS were used for the confirmation of the structures of the synthesized hybrids. Moreover, the antioxidant profiles of amides were estimated as per five different in vitro methods: 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2′-azinobis-3-ethylbenzothiazoline-6-sulfonic acid cation radical (ABTS⁺), ferric reducing antioxidant power (FRAP), cupric reducing antioxidant capacity (CUPRAC) assay, and inhibition of Fe(III)/asc induced lipid peroxidation (LP) in brain homogenate. For comparison, caffeic acid (CaffA), known as a potent naturally occurring antioxidant, was used as a reference compound in our study. The results revealed that the most prominent antioxidant activity was demonstrated by compound 4b2, with excellent CUPRAC, FRAP, scavenging ABTS+˙ potential, and inhibition of Fe/asc–induced LP, followed by 4c6 &gt; 4a6 &gt; CaffA &gt; 4c5 and 4a5 &gt; 4a7. Overall, the results suggest that the hybrids (4b2, 4c6, and 4a6) consisting of a caffeoyl moiety and lipophilic adamantane core endow the molecules with the higher antioxidant activity than their parent compound (caffeic acid), especially against LP. Thus, these promising antioxidants could have beneficial effects in various pathological conditions, where oxidative stress is implicated.

Chemical Composition and Antioxidant Properties of Common and Lemon Verbena.

The nutritional profiles of common and lemon verbena leaves were analyzed (proximate constituents, free sugars, organic acids, tocopherols, and fatty acids) and the leaves were prepared in hydromethanolic and aqueous (decoctions and infusions) extracts. The phenolic compound composition and antioxidant activity (2,2-Diphenyl-1-picrylhydrazyl (DPPH); 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS), ferric-reducing antioxidant power (FRAP); and cupric-reducing antioxidant capacity (CUPRAC) assays) of the extracts were characterized. The nutritional composition varied between the studied species, with lemon verbena showing higher amounts of protein, ash, and fat than common verbena, whereas the opposite trend was recorded for the dietary fiber content. The main free sugars detected in both species were fructose, glucose, and sucrose, which were present in higher amounts in the common verbena samples. Succinic acid was the most abundant organic acid in both species while high amounts of oxalic acid were detected in lemon verbena. The main fatty acids in both species were α-linolenic, palmitic, and linoleic acid. Regarding the phenolic compound content, the extracts of lemon verbena presented higher amounts of total phenolic compounds (TPCs), total flavonoids (TFs) and total phenolic acids (TPAs) than the common verbena extracts while the aqueous extracts (infusions and decoctions) were richer in TPCs, TFs, and TPAs than the hydromethanolic ones in both species. Nine phenolic compounds were identified and quantified, including seven phenolic acids and two flavonoids. The lemon verbena samples were characterized by higher antioxidant activity compared to the common verbena samples while the aqueous extracts showed higher antioxidant efficacy than the hydromethanolic ones. In conclusion, both species showed promising results in terms of the nutritional value, chemical composition, and antioxidant activities, which were positively correlated with the phenolic compound contents. Moreover, the extraction protocol may affect the chemical composition and bioactive properties of both species, with aqueous extracts showing better results than hydromethanolic ones.

GC-MS Chemical Profiling, Biological Investigation of Three Salvia Species Growing in Uzbekistan.

Salvia is a potentially valuable aromatic herb that has been used since ancient times. The present work studied the chemical profile of three Salvia species essential oils (EO): S. officinalis, S. virgata and S. sclarea, as well as assessing their antioxidant and enzyme inhibitory activities. A total of 144 compounds were detected by GC-MS analysis, representing 91.1, 84.7 and 78.1% in S. officinalis, S. virgata and S. sclarea EOs, respectively. The major constituents were cis-thujone, 2,4-hexadienal and 9-octadecenoic acid, respectively. The principal component analysis (PCA) score plot revealed significant discrimination between the three species. The antioxidant activity of the EOs was evaluated using in vitro assays. Only S. virgata EO showed antioxidant activity in the 2,2-diphenyl-1-picryl-hydrazyl (DPPH) assay (26.6 ± 1.60 mg Trolox equivalent (TE)/g oil). Moreover, this oil exhibited the highest antioxidant activity in 2,2-azino bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), cupric-reducing antioxidant capacity (CUPRAC) and ferric-reducing power (FRAP) assays in comparison with the other two EOs (190.1 ± 2.04 vs. 275.2 ± 8.50 and 155.9 ± 1.33 mg TE/g oil, respectively). However, S. virgata oil did not show any effect in the chelating ability assay, while in the PBD assay, S. officinalis had the best antioxidant activity (26.4 ± 0.16 mmol TE/g oil). Enzyme inhibitory effect of the EOs was assessed against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), tyrosinase, α-glucosidase and α-amylase. AChE enzyme was more sensitive to S. officinalis EO (4.2 ± 0.01 mg galantamine equivalent (GALAE)/g oil), rather than S. virgata EO, which was ineffective. However, S. virgata had the highest BChE effect (12.1 ± 0.16 mg GALAE/g oil). All studied oils showed good tyrosinase inhibitory activity, ranging between 66.1 ± 0.61 and 128.4 ± 4.35 mg kojic acid equivalent (KAE)/g oil). Moreover, the EOs did not exhibit any glucosidase inhibition and were weak or inefficient on amylase enzyme. Partial least squares regression (PLS-R) models showed that there is an excellent correlation between the antioxidant activity and the volatile profile when being compared to that of enzyme inhibitory activity. Thus, the studied Salvia essential oils are interesting candidates that could be used in drug discovery for the management of Alzheimer’s and hyperpigmentation conditions.

Chemical Composition, Antioxidant and Anti-Enzymatic Activity of Golden Root (Rhodiola rosea L.) Commercial Samples

The aim of the study was to compare the chemical composition of the water and hydromethanolic extracts of R. rosea commercial samples in relation to their biological activity. For this purpose, the HPLC method was used for the determination of eleven phenolic compounds and AAS/AES was used for determination of five essential elements. Moreover, the contents of total phenolic, total flavonoid, total phenolic acids, and L(+)-ascorbic acid were determined. The antioxidant activity was assessed by DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS radical scavenging activity, ferric-reducing/antioxidant power (FRAP), and cupric-reducing antioxidant capacity (CUPRAC) assays, while the inhibitory activity against AChE and BChE enzymes was determined using Ellman’s method. The results showed that the hydromethanolic extracts of R. rosea were richer in phenolic compounds and showed higher antioxidant and neurobiological activity than the water extracts. However, the water extracts gave higher contents of determined elements. Among the individual phenolic compounds gallic acid (2.33 mg/g DW) and sinapic acid (386.44 µg/g DW) had the highest concentrations in the hydromethanolic and water extracts, respectively. Moreover, the most extracts were observed to be more efficient on BChE. Moreover, the correlation analysis indicated a high positive relationship between chemical composition and biological activity in both extracts of R. rosea.

Organic vs conventional farming of oil-bearing rose: Effect on essential oil and antioxidant activity

The aim of this study was to establish whether the type of the agricultural system has any influence on the essential oil production and antioxidant activity of industrial cultivated Rosa damascena Mill. in the Rose valley, Bulgaria. Six private farms from Kazanlak (Rose) Valley, Southern Bulgaria were included in the study conducted in the period 2019–2020. The first three selected farms are designated within the conventional farming and the other three are certificated as organic farms. GC/FID and GC/MS analyses were performed; the contents of total polyphenols and flavonoids in the methanol extracts from rose petals were determined. Additionally, the antioxidant activity of rose extracts was evaluated by four reliable methods: 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2´-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS), ferric reducing antioxidant power (FRAP), and cupric reducing antioxidant capacity (CUPRAC) assays. The impact of the agricultural system on the essential oil composition and antioxidant activity was evaluated by ANOVA statistical analysis. The results obtained showed that organic farming produced essential oil with a higher linalool and geraniol content and lower β-citronellol + nerol concentrations than conventional farming. It was found that organic farming production demonstrated a better antioxidant activity evaluated by the three DPPH, ABTS, and CUPRAC methods according to the averaged data for two years, 806.82, 797.66 and 1534.40 mM TE/g dw versus 510.34, 521.94 and 917.48 mM TE/g dw for CF, respectively, with high statistical significance for the DPPH and ABTS analyses. Consequentially, the rose extracts from the organic farming accumulated more phenolic compounds that corresponded to the higher antioxidant potential of the organic roses.

Comparison of Important Quality Characteristics of Some Fungal Disease Resistance/Tolerance Grapes Dried with Energy-Saving Heat Pump Dryer

Raisins have been widely consumed for many years all around the world, and different grape cultivars and drying techniques are used in their production. Recently, mechanical drying systems have been used to overcome any undesirable effects that arise from sun-drying with grape cultivars that require fewer pesticides to minimize the risk of residues. Both seeded and seedless cultivars were preferred for drying in the past; however, seedless grape cultivars have been increasingly preferred for drying purposes in addition to their use as table grapes. For the first time, an alternative processing method (using an energy-saving heat pump dryer) and important quality characteristics (total phenolics, antioxidant activity, brix, colour analyses and sensory evaluation) of disease resistant/tolerant grape cultivars of different species that can be grown in humid regions were investigated in this study. First, the fresh fruits of nine different grape (Vitis spp.) cultivars grown in a humid ecology were analysed, and then so too were the important phytochemical and quality characteristics of raisins dried with an energy-saving heat pump dryer. The water activity of the raisins ranged from 0.71 (Özer Beyazı) to 0.42 (Kay Gray). The total phenolic contents of Muscat Bleu (65.96), Philipp (64.88) and Campbell Early (64.53 g GAE/100 g db) berries were the highest (p &lt; 0.05). The fresh berries of the Kishmish Vatkana cultivar had the lowest antioxidant activity, as determined by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay (525.81 mmol TE/100 g) (p &lt; 0.05). The total phenolic contents of raisins ranged from 12.76 to 13.58 g GAE/100 g fw. The highest value on a dry weight basis was 19.30 g GAE/100 g for the raisins of the Özer Beyazı cultivar (p &lt; 0.05). The highest antioxidant activity value on a dry weight basis was found for the raisins of Özer Beyazı (991.01 mmol TE/100 g) using the DPPH assay. The raisins of the Philipp cultivar had an antioxidant activity of 7893.51 mmol TE/100 g db, as determined by the ferric reducing antioxidant potential (FRAP) assay, which was significantly higher than those of other cultivars, with the exception of Muscat Bleu (p &lt; 0.05). The range for antioxidant activity values provided by the cupric reducing antioxidant capacity (CUPRAC) assay was high, and the highest value was found for the raisins of the Philipp cultivar (4505.21 mg Trolox/100 g fw) (p &lt; 0.05). The results indicated that the raisins of the seedless Rhea and Kishmish Vatkana cultivars can be appreciated more than those of the other cultivars, both in terms of their bioactive content and sensory scores, and the raisins of these cultivars, which can be grown in humid regions, hold a great deal of potential for grape growers.

The role of Gentiana lutea extracts in reducing UV-induced DNA damage.

Ultraviolet (UV) radiation can result in DNA damage, mainly through direct formation of pyrimidine dimers and generation of reactive oxygen species, which can lead to the skin disorders including cancer. In accordance with this, the use of natural antigenotoxins and/or antioxidants could contribute to human health protection. Considering that plants are rich in both, the aim of this study was to investigate UV-protective and antioxidative properties of yellow gentian (Gentiana lutea), being well established in pharmacopeias and traditional medicine. Tested extracts were derived from root and shoot of the in vitro cultivated plants. Prescreening of the genotoxic properties of UVC, UVA, and the extracts, as well as the extracts' antigenotoxicity were estimated by applying alkaline comet assay on normal fetal lung fibroblast (MRC-5) and human melanoma cells (Hs 294T). Antioxidant potential was tested in ferrous ions chelating ferric reducing antioxidant power and cupric reducing antioxidant capacity assays. Genotoxicity testing, which revealed moderate DNA-damaging potential of root extract on MRC-5 cells and high genotoxicity of shoot extract on both cell lines, pointed out nongenotoxic concentrations that could be used in antigenotoxicity assay. Doses of 63 and 3 J/cm2 for UVC and UVA, respectively, were established for antigenotoxicity study, since they induced sufficient DNA damage without notable cytotoxicity. Results of antigenotoxicity revealed strong protective effect of both extracts against UVC (the highest inhibitions 58% and 47%) and UVA (the highest inhibitions 69% and 60%), in Hs 294T and MRC-5 cells, respectively. Study of the antioxidative properties demonstrated stronger activity of shoot extract. Results obtained proved to be encouraging but further research of the UV-protective role of Gentiana lutea extracts and underlying molecular mechanisms is recommended.