Concentration-dependent Antioxidant Activity Research Articles

Acute Cardioprotective and Cardiotoxic Effects of Bilberry Anthocyanins in Ischemia–Reperfusion Injury: Beyond Concentration-Dependent Antioxidant Activity

Despite being reported to reduce the risk of cardiovascular diseases, little is known about acute direct effects of bilberry anthocyanins on whole mammalian heart under ischemia-reperfusion (I-R) conditions. Bilberry anthocyanins were prepared from the ripe bilberries and analyzed using HPLC-DAD. Their antioxidant activity was evaluated by measuring the intrinsic free radical-scavenging capacity and by cellular antioxidant assay (CAA) on endothelial cells, where we quantified the intracellular capacity to inhibit the formation of peroxyl radicals. Experiments on the isolated rat hearts under I-R were carried out according to the Langendorff method. Perfusion with low concentrations of bilberry anthocyanins (0.01-1mg/L) significantly attenuated the extent of I-R injury as evidenced by decreasing the release rate of LDH, increasing the postischemic coronary flow, and by decreasing the incidence and duration of reperfusion arrhythmias. High concentrations (5-50mg/L) diminished cardioprotection and show cardiotoxic activity despite having their radical scavenging and intracellular antioxidant capabilities increased in a concentration-dependent manner. This study reveals the biphasic concentration-dependent bioactivity of bilberry anthocyanins under I-R, which results in strong cardioprotective activity in low concentrations and cardiotoxic activity in high concentrations.

Dracaena draco L. fruit: Phytochemical and antioxidant activity assessment

The present study reports for the first time the metabolite profile and antioxidant activity of aqueous extract obtained from Dracaena draco L. fruit. Volatiles profile was determined by HS-SPME/GC-IT-MS, with 9 compounds being identified, distributed by several distinct chemical classes: 1 alcohol, 3 aldehydes, 2 carotenoid derivatives, and 3 terpenic compounds. Aldehydes constituted the most abundant class in this exotic berry, representing 59% of total identified volatile compounds. Phenolics profile was determined by HPLC/DAD and 5 constituents were identified: 5-O-caffeoylquinic, 3,5-O-dicaffeoylquinic, ferulic and sinapic acids, and quercetin-3-O-rutinoside. The major phenolic compound is quercetin-3-O-rutinoside, comprising 42% of the total phenolic content. Organic acids composition was also characterized, by HPLC-UV, and oxalic, citric, l-ascorbic, malic, quinic and shikimic acids were determined. The most abundant is quinic acid, representing 39% of the total organic acid content. The antioxidant potential of this matrix was assessed by (i) reducing power of Fe3+/ferricyanide complex, (ii) scavenging effect on DPPH free radicals, and (iii) ability to inhibit the 2,2´-azobis(2-amidinopropane) dihydrochloride (AAPH)-induced oxidative hemolysis in human erythrocytes. Strawberry (Fragaria×ananassa Duch. cv. Camarosa) extract was used for comparison purposes. All assay models showed remarkable concentration dependent antioxidant activity, reducing power and radical scavenging efficiency for D. draco fruit, being invariably higher than that of strawberry extract. This is the first report showing that D. draco fruit is a promising new antioxidant agent.

Antioxidant and prooxidant nature of hydroxycinnamic acid derivatives ferulic and caffeic acids

Dietary polyphenols are beneficial to human health by exerting various biological effects. Ferulic and caffeic acids are hydroxycinnamic acid derivatives widely distributed in plant-derived food products. Studies indicate that some dietary compounds may have concentration-dependent antioxidant or prooxidant activities. The present study concerns such activities of ferulic and caffeic acids. They have concentration-dependent antioxidant effects in terms of inhibition of lipid peroxidation and reactive oxygen species-scavenging after 2,2′-azobis-amidinopropane dihydrochloride-induced damage in mouse liver microsomes and splenic lymphocytes respectively. They also show differential scavenging of nitric oxide, superoxide and 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulfonic acid radical (ABTS +). In DPPH (1,1-diphenyl picrylhydrazyl) assay above 20 μM the absorbance start increasing due to the formation of an unknown adduct which has a shoulder at 517 nm. However, in Fenton reaction, above 5 μM, they behave as prooxidants and the possible mechanisms responsible for their prooxidant property may be related to their ferric reducing ability. These findings may have significant health implications where these natural compounds are being used/consumed.

Preliminary phytochemical screening and antioxidant activity of leave extract of <i>Albizia chevalieri</i> harms (Leguminoseae-Mimosoideae)

Antioxidant evaluation of Albizia chevalieri used in Northern Nigerian traditional medicine, was carried out using the free radical scavenging activity of the 1, 1-diphenyl-2-picrylhydrazyl radical (DPPH), total phenolics content and reducing power assay on the methanol leave extract. The results of the DPPH scavenging activity study indicate a concentration dependent antioxidant activity with 59.588, 68.477, 77.240, 85.925 and 94.732% of various concentrations of 10, 25, 50, 125 and 250μg/ml of the extract respectively. The total phenolic content was found to be 60.20 mg/g Gallic acid equivalent (GAE) and the reducing power of 0.071±0.03nm was obtained. The DPPH scavenging activity of the extract was found to be promising. There is no significant difference (p

Negative pressure cavitation extraction and antioxidant activity of genistein and genistin from the roots of pigeon pea [ Cajanus cajan (L.) Millsp.

A new method—negative pressure cavitation extraction (NPCE) was proposed and investigated for the extraction of the main isoflavonoids, namely genistein and genistin from pigeon pea roots. The effects of extraction time and particle size on the extraction yields were firstly optimized, then a central composite design (CCD) combined with response surface methodology (RSM) was used to study the effects of negative pressure, ethanol concentration and liquid/solid ratio on the extraction yields. The maximum extraction yields of genistein and genistin reached 0.418 and 0.398 mg/g, respectively, under the optimal conditions: extraction time 45 min, particle size 50 mesh, negative pressure −0.05 MPa, ethanol concentration 70% and liquid/solid ratio 44:1. Furthermore, the antioxidant activity of NPCE extract was assessed by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging assay. NPCE extract possessed notable concentration-dependent antioxidant activity with IC 50 value of 0.062 mg/ml.

Antioxidant activity in vitro of the selenium-contained protein from the Se-enriched Bifidobacterium animalis 01

Several studies indicated that bifidobacteria possessed strong antioxidant activity. In present study, the antioxidant activities of Bifidobacterium animalis 01 proteins were evaluated using six assays, namely, linoleic acid preoxidation assay, erythrocyte hemolysis assay, 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay, reducing power assay, hydroxyl ( OH) and superoxide radicals ( O 2 −) assays, in which the last two assays were measured by electron spin resonance (ESR). There were two kinds of B. animalis 01 proteins in this study, the regular B. animalis 01 protein (Pro-CK) and the B. animalis 01 selenium-contained protein (Pro-Se). Both Pro-CK and Pro-Se showed concentration dependent antioxidant activity in DPPH assay, reducing power assay and erythrocyte hemolysis assay. All results of six assays indicated that the antioxidant activity of the B. animalis 01 protein was improved remarkably after selenium was incorporated. The antioxidant activity of Pro-Se increased with the increase of selenium content in Pro-Se suggesting selenium played a positive role in enhancing the antioxidant activity of B. animalis 01 protein. Moreover, organic selenium was more effective than inorganic selenium on enhancing the hydroxyl radical scavenging ability of B. animalis 01 protein.

Chemoprotective Effects of Zataria multiflora Against Genotoxicity Induced by Cyclophosphamide in Mice Bone Marrow Cells

The preventive effective of Zataria multiflora (ZM) extract was investigated in mouse bone marrow cells against genotoxicity induced by cyclophosphamide (CP). Mice were orally (gavaged) pretreated with solutions of ZM extract prepared at 3 different doses (50, 100, and 200 mg/kg body weight) for 7 consecutive days. They were injected with CP (50 mg/kg body weight) on the seventh day of treatment and killed after 24 hours for the evaluation of micronucleated polychromatic erythrocytes (MnPCEs) and the ratio of PCE/(PCE + NCE), where PCE refers to polychromatic erythrocyte, and NCE refers to normochromatic erythrocyte. All 3 doses of extract significantly reduced MnPCEs induced by CP (P < .0001). Zataria extract at a dose of 200 mg/kg body weight reduced MnPCEs 7.8 fold and also completely normalized the PCE/ (PCE + NCE) ratio. Administration of ZM inhibited bone marrow suppression induced by CP. Zataria extract exhibited concentration-dependent antioxidant activity on 1, 1-diphenyl 2-picryl hydrazyl free radical and lipid peroxidation. It appeared that ZM with antioxidative activity reduced the oxidative stress and genotoxicity induced by CP in mouse bone marrow cells.

Characteristics and Antioxidant Activity of Elsholtzia splendens Extract-Loaded Nanoparticles

Elsholtzia splendens extract-loaded chitosan nanoparticles prepared by ionic gelation were characterized by particle size, zeta potential, entrapment efficiency, and loading efficiency. As the initial concentration of E. splendens extract was increased, the loading efficiency and zeta potential significantly increased, whereas the entrapment efficiency and particle size significantly decreased. The optimum concentration of E. splendens extract for maximum loading efficiency was found to be 0.8 mg/mL. Both free E. splendens extract and E. splendens extract-loaded chitosan nanoparticles showed concentration-dependent antioxidant activity. However, the lipid peroxidation inhibitory activity of E. splendens extract was effectively enhanced when it was entrapped within chitosan nanoparticles. Chitosan nanoparticle encapsulation is therefore a potentially valuable technique for improving the antioxidant activity of E. splendens extract.

Antioxidant Effects of Glechoma hederacea as a Food Additive

The antioxidant properties of Glechoma hederacea L. (Lamiaceae), of Serbian origin, were studied in respect to its potential use in foodstuffs. Ethanol-water (8:2, v/v) and purified ethyl acetate extracts of the plant were found to possess significant antioxidant activity. Tests were performed on two different substrates, prime steam pork lard and active-carbon-treated edible sunflower oil, using Schaal oven test storage conditions at 60 degrees C. The ethanol-water and purified ethyl acetate extracts of G. hederacea showed strong concentration-dependent antioxidant activity. On the contrary, under the Rancimat method conditions at 120 degrees C, the ethanol-water extract showed significantly stronger antioxidant activity, in comparison with the other tested extracts. All activities were compared with commercial antioxidants, such as BHA and a tocopherol mixture, respectively. For the first time, the activity of the flavonol quercetagetin was determined.

Supercritical carbon dioxide extraction of seed oil from yellow horn ( Xanthoceras sorbifolia Bunge.) and its anti-oxidant activity

Supercritical fluid carbon dioxide (SF-CO 2) extraction (SFE) of seed oil from yellow horn and its anti-oxidant activity were investigated. The effects of CO 2 flow rate and particle size were firstly optimized, and a central composite design (CCD) combined with response surface methodology was used to study the effects of extraction pressure, temperature and time on the extraction yields. A maximal extraction yield of 61.28% was achieved under optimal conditions of extraction pressure 30 MPa at 45.68 °C, 2.08 h and CO 2 flow rate 12 kg/h with 0.5 mm particle size. By analyzing the chemical composition of the seed oil, we found that the content of unsaturated fatty acids was approximately 90%. Furthermore, the anti-oxidant activity of seed oil was assessed by a 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging assay and a β-carotene bleaching test. Yellow horn seed oil possessed notable concentration-dependent anti-oxidant activity with IC 50 values of 0.151 and 0.195 g/mL, respectively.

Pharmacological inhibition of ABCA1 degradation increases HDL biogenesis and exhibits antiatherogenesis

Expression of ABCA1 is regulated by transcription of the gene and calpain-mediated proteolytic degradation, and inhibition ABCA1 degradation results in increased ABCA1 and HDL biogenesis in vitro. We examined whether this approach could be a potential antiatherogenic treatment. Although probucol inhibits both the activity and degradation of ABCA1, its oxidized products, spiroquinone and diphenoquinone, reduce degradation of ABCA1 without inhibiting its activity or altering transcription of the ABCA1 gene. Accordingly, both compounds enhanced apolipoprotein A-I/ABCA1-dependent generation of HDL in vitro, and increased hepatic ABCA1 and plasma HDL without increasing antioxidant activity in plasma when given to rabbits. Both compounds also decreased vascular lipid deposition in cholesterol-fed rabbits. We therefore conclude that stabilization of ABCA1 against calpain-mediated degradation is a novel and potentially important strategy to increase HDL formation and prevent atherosclerosis. Spiroquinone and diphenoquinone are potential seeds for development of such drugs.

Evaluation of antioxidant activity of leave extract of Bauhinia rufescens Lam. (Caesalpiniaceae)

Antioxidant evaluation of Bauhinia rufescens used in Northern Nigerian traditional medicine, was carried out using 1, 1-diphenyl-2-picrylhydrazyl radical (DPPH) and reducing power assay on the methanolic extract of the leaves. The results of the DPPH scavenging activity indicate a concentration dependent antioxidant activity with no significant difference (p < 0.05) at 50, 125 and 250 µgml-1 with those of the standard ascorbic and gallic acids. The total phenolic content was determined and found to be 68.40 ± 0.02 mg/g gallic acid equivalent (GAE) and the reducing power of 0.071 ± 0.03 nm was obtained. The phytochemical screening revealed the presence of flavonoids, tannins and saponins whose synergistic effect may be responsible for the strong antioxidant activity. It indicates that the methanolic extract of the leave may have promising antioxidant agents and may also help in the treatment of the diseases caused by free radicals. Key words: Antioxidants, free radicals, Bauhinia rufescens, DPPH, reducing power, total phenolics.

Protection of PC12 cells from chemical ischemia induced oxidative stress by Fagonia arabica

Fagonia arabica (Zygophyllaceae) is an important Ayurvedic herb, grows throughout arid regions of India, has been widely used as a folk remedy by the indigenous people for its anti-inflammatory, analgesic and antipyretic effects. In the present study, antioxidant potential of F. arabica and the associated mechanism of antioxidant defence in rat pheochromocytoma (PC12) cells subjected to chemical ischemia was studied. Effect of total extract of F. arabica was studied for its antioxidant potential on the chemical ischemia induced PC12 cells. Alterations in the activities of cellular antioxidant enzymes (SOD, CAT, GSH-Px and GSH-R) were measured. Antioxidant potential of herb (ABTS), extent of lipid peroxidation (MDA and 4-HAE), total antioxidant status (TAS) and total glutathione (reduced, oxidized and their ratio) were evaluated. F. arabica scavenges the free radicals (ABTS +), and showed a concentration dependent antioxidant activity, highest being at 1000 μg/ml. Its treatment with ischemic cells ameliorates the GSH and TAS levels and also helps the cells to restore the activities of the cellular antioxidative enzymes and also reduced the degree of lipid peroxidation. F. arabica scavenges the free radicals and attenuates oxidative stress mediated cell injury during ischemia.

Antioxidant activity of Rhizoma Smilacis Glabrae extracts and its key constituent-astilbin

Rhizoma Smilacis Glabrae is widely consumed by Chinese as functional food and in folk medicine for its medicinal properties. In this study, methanol and water extracts of Rhizoma Smilacis Glabrae were prepared. The water extract was further divided into polysaccharide and supernatant fractions. Constituents in different extracts were analysed by capillary electrophoresis, and levels of total phenolics were also determined using the Folin-Ciocalteu method. Astilbin, the main constituent in the herb, was isolated and purified. Different antioxidant tests were employed to evaluate the antioxidant activities of the extracts and the isolated astilbin, and the results were compared with two commonly used synthetic antioxidants-butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT). Methanol, water extract and supernatant fraction showed concentration dependent antioxidant activity while polysaccharide didn’t show any antioxidant activity. Purified astilbin showed the strongest antioxidant activity in comparison to any other extracts.

Antioxidant and antimicrobial activity of Cynara cardunculus extracts

The whole, fresh involucral bracts of cardoon, Cynara cardunculus L. (Compositae), were extracted with EtOH and an aqueous suspension of the obtained EtOH extract was partitioned successively with CHCl 3, EtOAc and n-BuOH, leaving a residual water extract. All obtained extracts were evaluated for their antioxidant and antimicrobial properties. The antioxidant potential was evaluated using following in vitro methods: FRAP (ferric reducing antioxidant power) assay, and scavenging of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical. Antimicrobial activity was estimated using a microdilution technique against food-borne, mycotoxin producers and human pathogenic bacteria and micromycetes. The following bacteria were tested: Salmonella typhimurium, Escherichia coli, Bacillus subtilis, Staphylococcus epidermidis, Staphylococcus aureus, as well as micromycetes: Aspergillus niger, Aspergillus ochraceus, Aspergillus flavus, Penicillium ochrochloron, Penicillium funiculosum, Trichoderma viride, Fusarium tricinctum and Alternaria alternata. Results showed that all extracts possessed concentration-dependent antioxidant activity. In biological assays, C. cardunculus extracts showed antimicrobial activity comparable with standard antibiotics.

Protective effect of hawthorn extract against genotoxicity induced by cyclophosphamide in mouse bone marrow cells

The preventive effect of hawthorn ( Crataegus microphylla) fruit extract was investigated in mouse bone marrow cells against genotoxicity induced by cyclophosphamide. Mice were orally (gavages) pretreated with solutions of hawthorn extract which was prepared at five different doses (25, 50, 100, 200 and 400 mg/kg b.w.) for seven consecutive days. Mice were injected intraperitoneally on the seventh day with cyclophosphamide (50 mg/kg b.w.) and killed after 24 h for the evaluation of micronucleated polychromatic erythrocytes (MnPCEs) and the ratio of PCE/(PCE + NCE) (polychromatic erythrocyte/polychromatic erythrocyte + normochromatic erythrocyte). All of five doses of extract significantly reduced MnPCEs induced by cyclophosphamide ( P < 0.0001). Hawthorn extract at dose 100 mg/kg b.w. reduced MnPCEs 2.5 time and also completely normalized PCE/(PCE + NCE) ratio. Hawthorn extract exhibited concentration-dependent antioxidant activity on 1,1-diphenyl-2-picryl hydrazyl free radical. Hawthorn contains high amounts of phenolic compounds; the HPLC analysis showed that it contained chlorogenic acid, epicatechin and hyperoside. It is obvious that hawthorn, particularly flavonoids constituents with antioxidative activity, reduced the oxidative stress and genotoxicity induced by cyclophosphamide in mouse bone marrow cells.

Influência do processamento e da torrefação sobre a atividade antioxidante do café (Coffea arabica)

The aim of this work is to evaluate the influence of processing (semi-dry and dry) and roasting (light, medium and dark) on the antioxidant activity of coffee brews, using tests to determine the reducing power and the DPPH scavenging, Fe+2 chelating and lipid peroxidation inhibition activities. All of the coffee brews presented concentration-dependent antioxidant activity. The light coffee samples presented the higher reducing power and DPPH scavenging activity. Its ion chelating capacity was similar to the medium samples, but was less than the green coffee chelating capacity. The semi-dry processing was more efficient than the dry processing only for the reducing power. All of the samples presented high lipid peroxidation inhibition activity. Based on the results the degree of coffee roasting seems to be more important than the processing to determine the antioxidant activity of brews.

Identification of Antioxidants in Essential Oil of Radix Angelicae Sinensis Using HPLC Coupled with DAD-MS and ABTS-Based Assay

Radix Angelicae sinensis (named danggui in Chinese), a commonly used traditional Chinese medicine, has multiple pharmacological activities. The essential oil of danggui is usually considered to be its main active fraction. However, to date, studies on the antioxidant potentials of danggui have focused on water-soluble compounds. In this paper, the antioxidant activity of the commercial essential oil of danggui was investigated by DPPH radical scavenging assay, ABTS radical scavenging assay, and beta-carotene bleaching test. Antioxidant constituents in the essential oil were identified using HPLC coupled with DAD-MS and ABTS-based assay. The results showed that the essential oil of danggui has concentration-dependent antioxidant activity, which can be attributed to its component (coniferyl ferulate). This is the first report on the antioxidant activity of essential oil from danggui; its antioxidant potential was lower than those of positive controls, ascorbic acid and BHA.

산삼과 산양삼 추출물의 항암 및 항산화 효능

Objectives : The aim of this study was to verify anti-cancer and anti-oxidant efficacies of Korean wild ginseng and cultivated wild ginseng of Korea and China. Methods : For the measurement of anti-oxidation, SOD-like activity was evaluated using xanthine oxidase reduction method under in vitro environment. Subcutaneous and abdominal cancer were induced using CT-26 human colon cancer cells for the measurement of growth inhibition of cancer cells and differences in survival rate. Results : 1. Measurement of anti-oxidant activity of ginseng, Chinese and Korean cultivated wild ginseng, and natural wild ginseng samples showed concentration dependent anti-oxidant activity in HX/XOD system. Anti-oxidant activity showed drastic increase at 1mg/ml in all samples. 2. For the evaluation of growth inhibition of cancer cells after hypodermic implantation of CT-26 cancer cells in the peritoneal cavity of mice, Chinese and Korean cultivated wild ginseng and natural wild ginseng groups showed significant inhibition of tumor growth from the 12th day compared to the control group. Similar inhibitory effects were also shown on the 15th and 18th days. But there was no significant difference between the experiment groups. 3. For the observation of increase in survival rate of the natural wild ginseng group, CT-26 cancer cells were implanted in the peritoneal cavity of mice.

Captopril protects mice bone marrow cells against genotoxicity induced by gamma irradiation

The radioprotective effects of captopril were investigated by using the micronucleus test for anticlastogenic and cell proliferation activity. A single intraperitoneal administration of captopril at doses of 10, 25 and 50 mg/kg 1 h prior to gamma irradiation (2 Gy) reduced the frequencies of micronuleated polychromatic erythrocytes (MnPCEs). All three doses of captopril significantly reduced the frequencies of MnPCEs and increased polychromatic erythrocytes (PCE)/PCE+NCE (normochromatic erythrocyte) ratio in mice bone marrow compared to the non-drug-treated irradiated control (p < 0.001). The optimum dose for protection in mouse was 10 mg/kg to protect mice bone marrow 2.18-fold against the clastogenic effects of gamma-irradiation with respect to the non-drug-treated irradiated control. There was a drug dose-response effect of captopril in increasing the PCE/PCE+NCE ratio in bone marrow cells. The maximum protective effect of captopril was at a dose of 25 mg/kg for increasing the PCE/PCE + NCE ratio. Captopril exhibited concentration-dependent antioxidant activity, scavenging > 96% of the 1,1-diphenyl-2-picryl hydrazyl free radicals when used at a concentration of 0.2 mM. In this study captopril reduced lipid peroxidation induced by hydrogen peroxide in mice liver. It appears that captopril, due to its free radical scavenging properties, protects mice bone marrow cells from radiation-induced DNA damage and genotoxicity.