Antioxidant Activity of Eugenol And Its Acetyl And Nitroderivatives: A DFT Approach of DPPH Test.

This work evaluates the antioxidant potential of acetyl and nitro derivatives of eugenol through computational techniques. Structural analysis and Hydrogen Atomic Transfer (HAT) antioxidant mechanism were investigated by density functional theory (DFT). Each molecular structure was optimized by the hybrid functional M06-2X with a basis set 6-31+G(d,p), and the HAT mechanism with HO, HOO, CH3O, DPPH radicals was evaluated. In agreement with experimental data from previous studies, two steps of hydrogen transfer were tested. Thermodynamic data showed the need for two stages of hydrogen transfer, followed by the formation of quinones to make the reaction with DPPH spontaneous. Theoretical kinetic data showed that the preferred antioxidant site depends on the instability of the attacking radical and confirmed the antioxidant profile of eugenol (E1) and 5-allyl-3-nitrobenzene-1,2-diol (E5) in the DPPH test. This study shows that the 4-allyl-2-methoxy-(4-nitrophenol) (E4) structure also has an anti-radical activity that is not seen in the experimental due to chemoselectivity of DPPH.

Formulation of a novel anti-human bone tumor supplement by silver nanoparticles green-synthesized using Nigella sativa leaf aqueous extract

IntroductionIn the present research, we formulated a modern chemotherapeutic drug by silver nanoparticles (AgNPs) containing Nigella sativa aqueous extract for the treatment of bone tumor.Material and methodsCharacterization of AgNPs was done by UV–Visible Spectroscopy (UV-Vis), Fourier Transformed Infrared Spectroscopy (FT‐IR), Transmission Electron Microscopy (TEM), and Field Emission Scanning Electron Microscopy (FE‐SEM). For investigating the antioxidant properties of AgNO3, N. sativa, and AgNPs, the DPPH test was used in the presence of butylated hydroxytoluene as the positive control. To survey the cytotoxicity and anti-bone tumor effects of AgNO3, N. sativa, and AgNPs, MTT assay was used on the human bone Ewing’s sarcoma (CADO-ES1 and MHH-ES1), human bone osteosarcoma (HOS and MG-63), and human bone chondrosarcoma (SW-1353 and CH-3573) cell lines.ResultsDPPH test revealed similar antioxidant potentials for N. sativa, AgNPs, and butylated hydroxytoluene. Silver nanoparticles had very low cell viability and anti-bone tumor properties dose-dependently against CADO-ES1, MHH-ES1, HOS, MG-63, SW-1353, and CH-3573 cell lines without any cytotoxicity on the normal cell line. The best result of anti-bone tumor properties of AgNPs against the above cell lines was seen in the case of the MG-63 cell line.ConclusionsAccording to the above findings, the silver nanoparticles containing N. sativa aqueous extract can be administrated in humans for the treatment of several types of bone tumors.

Antioxidant potential, anti-inflammatory activity, antidiabetic and cardioprotective effect of Microsechium helleri(Peyr.) Cong.

Microsechium helleri(Cucurbitaceae) has been used in ethnopharmacological as a lotion to prevent hair loss, diuretic and cathartic, in the region of central Veracruz, Mexico is used as antidiabetic. The antioxidant properties of the hexanic (EHex), chloroformic (ECHCl3) and ethanolic (EEtOH) extracts, were evaluated by 2,2diphenyl-1-pychrylhydrazyl (DPPH) test, the Ferric Reducing/Antioxidant Power (FRAP) and the total phenolic content test. The anti-inflammatory effect was evaluated in the acute ear edema induced with phorbol 12-myristate 13-acetate (TPA) in mouse and the hypoglycemic and cardioprotective effects of the EEtOH were determined in rats. The EEtOH was the most active in the antioxidant potential DPPH test and the ECHCl3was the best in the FRAP assay and the total polyphenols content. In the anti-inflammatory assay, the ECHCl3showed the most activity. The EEtOH had the decreased the glucose levels and reduced myocardial damage. The results support the use of this plant in folk medicine in Mexico as antioxidant, anti-inflammatory, hypoglycemic and cardioprotective.

Aktywność biologiczna ekstraktów z propolisu

Introduction. Propolis, also known as bee glue, is a resinous material collected by honeybees with numerous biological properties, including antibacterial, antifungal, antioxidant and anticancer effects. Due to its health-promoting properties, propolis is a component of many products, including dietary supplements, cosmetics and healthy food. Aim. The aim of the study was to determine the antibacterial, antifungal and antioxidant activity of propolis extracts, as well as to compare the biological activity of propolis extracts, depending on the solvent used – ethyl alcohol or propylene glycol. Material and methods. Two propolis extracts were used in the research – the first was prepared in ethyl alcohol, and the second in propylene glycol. The antimicrobial activity of the examined extracts was determined against S. aureus, E. coli and C. albicans. The antioxidant activity was determined on the basis of the evaluation of their antiradical activity in the DPPH· test and Fe2+ chelating activity. Moreover, the total content of phenolic compounds and flavonoids in the tested extracts was determined using the colorimetric method. Results. The tested propolis extracts, regardless of the solvent used (ethyl alcohol or propylene glycol), showed high antibacterial (against S. aureus), antifungal (against C. albicans) and antioxidant (antiradical activity in the DPPH· test and ferrous iron chelating potency in the ferrozine test) activity. Moreover, both tested extracts were characterized by a high and similar content of bioactive compounds – phenolic compounds and flavonoids. Conclusions. The results of the conducted tests showed that the solvent used did not affect determined biological activity and the content of bioactive substances in the tested propolis extracts.

Antioxidant activity of vitamin E homologues in model systems

The effect of tocopherols, tocotrienols and plastochromanol-8 in the inhibition of lipid peroxidation of liposomes prepared from natural chloroplast lipids, initiated by both water-soluble and lipid soluble azo-compounds, has been studied. In the case of tocopherols, α-tocopherol showed nearly no effect in the inhibition of lipid peroxidation, while β-, γ- and δ-tocopherols inhibited the reaction completely when it was initiated by lipid-soluble AMVN. Similar effects were observed for tocotrienol homologues. In the investigated reaction plastochromanol-8 was as effective as β-, γ- and δ-tocochromanols. When peroxidation was initiated by water-soluble AIPH in liposomes, the order and extent of inhibition was similar to those of AMVN initiator. However, in this case, α-tocopherol and α-tocotrienol showed more pronounced inhibition. When the prenyllipids were investigated in DPPH test, when incorporated into soy lipid liposomes, mixed micelles and micelles, DPPH oxidation was most pronounced in liposomes, followed by mixed micelles and micellar system. When the reaction of α-tocopherol, α-tocotrienol, plastochromanol-8 and α-tocopherol phosphate was examined in niosomes, the oxidation was most pronounced for α-tocopherol and plastochromanol-8, followed by α-tocotrienol. α-tocopherol phosphate showed no activity in this respect. The obtained results were discussed in light of the prenyllipid structures and their localization in the investigated lipid systems.

Electroactive Phenolic Contributors and Antioxidant Capacity of Flesh and Peel of 11 Apple Cultivars Measured by Cyclic Voltammetry and HPLC–DAD–MS/MS

In this study, 11 apple cultivars were characterized by their total phenolic content (TPC) and total flavonoid content (TFC) and antioxidant, reducing, and chelating capacity by 2,2-diphenyl-1-picrylhydrazyl (DPPH) test, cyclic voltammetry (CV), and ferric reducing antioxidant power (FRAP) assays; and ferrous ion chelating capacity. The phenolic compounds in flesh and peel were determined by liquid chromatography coupled to mass spectrometry and diode array detector (HPLC–DAD–MS/MS) and their electroactivity by CV. The results showed higher TPC, TFC, and antioxidant capacity by DPPH test in the peels of all apple cultivars as compared to the respective flesh. The peel extracts also showed two-fold higher FRAP values as compared to the flesh extracts. The reducing capacity of the peel and flesh determined by CV measurements confirmed the results achieved by spectrophotometric methods of evaluating antioxidant capacity. There was no significant difference in chelating capacity in the peel and flesh. The HPLC–DAD–MS/MS analysis showed the presence of 11 phenolic compounds in the peel and flesh which varied in antioxidant, reducing, and chelating activity. The order of the phenolic compound content in flesh and peel in Quinte cultivar, which showed the highest antioxidant capacity, was as follows: epicatechin > chlorogenic acid > quercetin 3-arabinoside > quercetin 3-glucoside > cyanidin 3-galactoside > quercetin 3-rhamnoside > catechin > phloridzin > rutin > phloretin = quercetin. CV results were highly correlated with those obtained by spectrophotometry and HPLC–DAD–MS/MS, providing evidence to support the use of cyclic voltammetry as a rapid method to determine the phenolic profile and reducing the power of apple flesh and peel. The association between antioxidant assays and phenolic compound content showed that the highest contribution to the antioxidant capacity of apple peel and flesh was provided by catechin, epicatechin, and cyadinin-3-galactoside, while phloretin, phloridzin, and chlorogenic acid were the main contributors to chelating activity. Results from this study clearly indicate that removing the peel from apples may induce a significant loss of antioxidants.

Antioxidant and anti-diabetic activity of pomegranate (Punica granatum L.) leaves extracts

Introduction. This study aimed to evaluate the antioxidant and anti-diabetic activity of aqueous and hydroalcoholic extracts of pomegranate (Punica granatum L.) leaves in vitro, as well as to determine the content of polyphenols, flavonoids, and flavonols. Study objects and methods. The antioxidant activity was determined by the DPPH test using the free radical 1,1-diphenyl-2-picrylhydrazyle and the FRAP method, as well as by measuring total antioxidant capacity and the hydrogen peroxide scavenging activity. Results and discussion. The content of total polyphenols varied between 4.43 ± 0.3 and 12.66 ± 1.6 mg EAG/g. The highest content of flavonoids was observed in the hydroalcoholic extract of P. granatum leaves (P < 0.05). The flavonol contents in the hydroalcoholic and aqueous extracts were 7.68 ± 0.6 and 9.20 ± 2.8 mg EQ/g, respectively. The IC50 of the antioxidant potential of the hydroalcoholic and aqueous extracts was 32.4 ± 1.109 and 35.12 ± 4.107 mg/mL, respectively. According to the DPPH test, the aqueous extract was the least active (IC50 = 14.15 ± 1.513 mg/mL). The highest percentage of hydrogen peroxide trapping was found in the aqueous extract (45.97 ± 6.608 %). The inhibition of α-amylase showed an IC50 of between 9.804 ± 0.67 and 19.011 ± 9.82 mg/mL in the aqueous and hydroalcoholic extracts, respectively. The inhibition of glucose uptake by yeast recorded a high inhibitory capacity at 50 mg/mL of glucose. Conclusion. We found that the antioxidant and anti-diabetic activity of P. granatum leaves extracts was due to the presence of bioactive compounds such as flavonoids, which is why they are effective in preventing diabetes and its complications.

Antioxidant Effect of the Castanea sativa Mill. Leaf Extract on Oxidative Stress Induced upon Human Spermatozoa

This study was aimed at evaluating in vitro the effects of a 75% v/v ethanolic extract of leaves of Castanea sativa Mill. (var. Bastarda Rossa, Mount Amiata, Tuscany, Italy) on ejaculated human sperm. Total polyphenols and total flavonoids contained in the extract were determined by a colorimetric assay and HPLC-DAD. The DPPH test and electrochemistry were utilized to study the antioxidant activity of the extract. Swim-up-selected sperm from 8 healthy men were treated with the C. sativa leaf extract at different dilutions (1 : 100, 1 : 200, and 1 : 500), and sperm motility was assessed following the WHO guidelines. Swim-up-selected spermatozoa were incubated with 100 μM H2O2 to induce lipid peroxidation (LPO) and with H2O2 and the leaf extract (1 : 100, 1 : 200, and 1 : 500) to test the antioxidant activity of the extract. The levels of LPO were determined by measuring malondialdehyde (MDA) concentrations. The treated samples were also analyzed by transmission electron microscopy (TEM) for ultrastructural evaluation. The chemical analysis showed that one-third ca. of the polyphenols in the C. sativa extract were made up of flavonoids, with hyperoside present in high concentration. A good antioxidant activity was demonstrated by both the DPPH test and electrochemical analysis. The C. sativa leaf extract did not decrease sperm motility at all tested dilutions. Treatment with H2O2 alone caused a significant increment in MDA levels (P=0.006993), while the treatment with H2O2 plus C. sativa extract diluted to 1 : 100 and 1 : 200 significantly reduced MDA levels (P=0.01476 and P=0.01571, respectively), with respect to H2O2 alone. TEM analysis confirmed the protective effect of the extract on damage induced by LPO, in particular that occurring at the plasma membrane level. The C. sativa leaf extract could be used in human and farm animal protocols for gamete handling, such as techniques of assisted reproduction and cryopreservation of semen, all conditions in which oxidative stress is exacerbated.

Evaluation of Skin Permeability of Resveratrol Loaded Liposomes and Nanostructured Lipid Carriers using a Skin Mimic Artificial Membrane (skin-PAMPA)

Background: The skin-PAMPA test is a quick and relatively deep tool in the early stages of drug discovery and formulation of dermal and transdermal delivery systems. Objective: This study focused on the application of the skin-PAMPA test to evaluate the permeation of Resveratrol (RSV) and also of two formulations, Liposomes (LP) and Nanostructured Lipid Carriers (NLC), prepared to improve RSV topical delivery. Methods: LP and NLC were physically and chemically characterized. Stability and in vitro release studies were also assessed in different pH media. The release results were applied to define the kinetic and mechanism of RSV release from the LP and NLC formulations. In vitro permeability was estimated through the skin-PAMPA and the antioxidant capacity was evaluated by DPPH test. Results: Nanoparticles have a spherical shape, dimensions suitable for skin application, and narrow size distribution. Encapsulation efficiency was 96.5% ± 2.1 for LP and 86.0% ± 2.4 for NLC. The formulations increased RSV solubility. Nanoparticles showed excellent physical and chemical stability during storage at 4°C for two months. In vitro release studies were performed at pH 5.5 and 7.4. The nanoparticles achieved a prolonged release of RSV. Skin-PAMPA proved an increased cutaneous permeability of RSV when loaded into LP or NLC. Both formulations maintained the antioxidant capacity of RSV, as evidenced by DPPH test. Conclusion: LP and NLC could be applied as drug delivery systems suitable for the topical delivery of the RSV. Skin-PAMPA has proved to be an effective tool for studying the permeability not only of the RSV but also of its formulations.

A Three-Step Approach to Estimation of Reduction Potentials of Natural Mixtures of Antioxidants Based on DPPH Test; Illustration for Catechins and Cocoa

The aim of this study is to propose a methodology to assess electrochemical properties of complex mixtures of antioxidants, such as plant extracts, based on the results of simple and popular DPPH test. The first, most difficult step, involves determinations of standard reduction potentials (E0) for the series of purified compounds (here catechins). The next step is the calculation of stoichiometric values (n10) based on the results of DPPH test for the same compounds. Finally, a correlation equation is formulated, which is then employed to estimate “cumulative reduction potential” (Ec) for the mixture of interest (here cocoa) using DPPH test results.