Antioxidants

436 KiB

Open AccessArticle

Phenolic Content of Hypodaphnis Zenkeri and Its Antioxidant Effects against Fenton Reactions’ Mediated Oxidative Injuries on Liver Homogenate

by Bruno Moukette Moukette, Constant Anatole Pieme, Prosper Cabral Nya Biapa, Jacques Romain Njimou, Vicky Jocelyne Ama Moor, Marco Stoller, Marco Bravi and Jeanne Yonkeu Ngogang

Antioxidants 2014, 3(4), 866-889; https://doi.org/10.3390/antiox3040866 - 16 Dec 2014

Cited by 13 | Viewed by 7507

Abstract

Under oxidative stress conditions, endogenous antioxidant defenses are unable to completely inactivate the free radicals generated by an excessive production of reactive oxygen species (ROS). This state causes serious cell damage leading to a variety of human diseases. Natural antioxidants can protect cells [...] Read more.

Under oxidative stress conditions, endogenous antioxidant defenses are unable to completely inactivate the free radicals generated by an excessive production of reactive oxygen species (ROS). This state causes serious cell damage leading to a variety of human diseases. Natural antioxidants can protect cells against oxidative stress. Hypaodaphnis zenkeri (H. zenkiri) is a plant consumed as a spice in the Cameroonian diet, and its bark has been used in traditional medicine for the treatment of several diseases. The present study aims at investigating the antioxidant activity, which includes free radical scavenging and protective properties of an extract from H. Zenkiri against oxidative damage on a liver homogenate. The free radical assays determined the scavenging activities of 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl (OH), nitrite oxide (NO) and 2,2-azinobis(3-ethylbenzthiazoline)-6-sulfonic acid (ABTS) radicals and the enzymes, whose protection was to be considered in the liver homogenate, including superoxide dismutase, catalase, and peroxidase. The antioxidative activities were studied using the ferric reducing antioxidant power (FRAP), reductive activity, and phosphomolybdenum antioxidant power (PAP) methods. In addition, the phenolic contents of the extracts were examined. The results showed that these extracts demonstrated significant scavenging properties and antioxidant activities, with the hydro-ethanolic extract of the bark of H. zenkeri (EEH) being the most potent. This extract had the highest total polyphenol (21.77 ± 0.05 mg caffeic acid (CAE)/g dried extract (DE)) and flavonoids (3.34 ± 0.13 mg quercetin (QE)/g dried extract) content. The same extract had significantly greater protective effects on enzyme activities compared to other extracts. The high performance liquied chromatography (HPLC) profile showed higher levels of caffeic acid, OH-tyrosol acid, and rutin in the leaves compared to the bark of H. zenkeri. In conclusion, the ethanolic and hydro-ethanolic extracts of the bark and leaves from H. zenkeri showed an antioxidant and protective potential against oxidative damage. Full article

(This article belongs to the Special Issue Analytical Determination of Polyphenols)

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1021 KiB

Open AccessArticle

A Cystine-Rich Whey Supplement (Immunocal^®) Delays Disease Onset and Prevents Spinal Cord Glutathione Depletion in the hSOD1^G93A Mouse Model of Amyotrophic Lateral Sclerosis

by Erika K. Ross, Aimee N. Winter, Heather M. Wilkins, Whitney A. Sumner, Nathan Duval, David Patterson and Daniel A. Linseman

Antioxidants 2014, 3(4), 843-865; https://doi.org/10.3390/antiox3040843 - 12 Dec 2014

Cited by 19 | Viewed by 13099

Abstract

Depletion of the endogenous antioxidant, glutathione (GSH), underlies progression of the devastating neurodegenerative disease, amyotrophic lateral sclerosis (ALS). Thus, strategies aimed at elevating GSH may yield new therapeutics for ALS. Here, we investigated the effects of a unique non-denatured whey protein supplement, Immunocal [...] Read more.

Depletion of the endogenous antioxidant, glutathione (GSH), underlies progression of the devastating neurodegenerative disease, amyotrophic lateral sclerosis (ALS). Thus, strategies aimed at elevating GSH may yield new therapeutics for ALS. Here, we investigated the effects of a unique non-denatured whey protein supplement, Immunocal^®, in the transgenic Gly position 93 to Ala (G93A) mutant hSOD1 (hSOD1^G93A) mouse model of ALS. Immunocal^® is rich in the GSH precursor, cystine, and is therefore capable of bolstering GSH content. Transgenic hSOD1^G93A mice receiving Immunocal^® displayed a significant delay in disease onset compared to untreated hSOD1^G93A controls. Additionally, Immunocal^® treatment significantly decreased the rate of decline in grip strength and prevented disease-associated reductions in whole blood and spinal cord tissue GSH levels in end-stage hSOD1^G93A mice. However, Immunocal^® did not extend survival, likely due to its inability to preserve the mitochondrial GSH pool in spinal cord. Combination treatment with Immunocal^® and the anti-glutamatergic compound, riluzole, delayed disease onset and extended survival in hSOD1^G93A mice. These findings demonstrate that sustaining tissue GSH with Immunocal^® only modestly delays disease onset and slows the loss of skeletal muscle strength in hSOD1^G93A mice. Moreover, the inability of Immunocal^® to rescue mitochondrial GSH in spinal cord provides a possible mechanism for its lack of effect on survival and is a limiting factor in the potential utility of this supplement as a therapeutic for ALS. Full article

(This article belongs to the Special Issue Oxidative Stress and Neurodegenerative Diseases)

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Immunocal® delays clinical onset in hSOD1G93A mice. (A) hSOD1G93A mice receiving Immunocal® ad libitum beginning at 60 days of age (pre-symptomatically) displayed a delay in disease onset and clinical decline compared to untreated mutant mice (n = 13). Onset curves are significantly different (p < 0.001) as determined by the Gehan–Breslow–Wilcoxon test. (B) Median survival is not significantly different between hSOD1G93A mice receiving Immunocal® ad libitum and untreated mutant mice (n = 13). Full article ">Figure 2
Immunocal® diminishes the rate of decline in grip strength in hSOD1G93A mice. (A) The paw grip endurance (PaGE) hanging wire test expressed as latency to fall at indicated ages (n = 13); (B) body weight of wild-type and hSOD1G93A mice expressed as the percent of peak body weight. All data are represented as the mean ± SEM. *** indicates p < 0.001 compared to non-transgenic (NonTG) mice; ** indicates p < 0.01 compared to NonTG; † indicates p < 0.05 compared to untreated hSOD1G93A mice (one-way ANOVA with a post hoc Tukey’s test conducted for each time point). Full article ">Figure 3
HPLC-EC detection reveals whole blood GSH is preserved in hSOD1G93A mice receiving Immunocal®. (A) Mean GSH and glutathione disulfide (GSSG) concentrations and GSH/GSSG ratios from the whole blood of end-stage trial animals determined using HPLC-EC detection, n = 13. ** indicates p < 0.01; * indicates p < 0.05; ns indicates no significant difference. (B) Representative HPLC-EC chromatograms from the whole blood of end-stage animals; labeled peaks indicate GSH oxidizing at 600 and 800 mV. Full article ">Figure 4
HPLC-EC detection reveals lumbar spinal cord GSH is maintained in hSOD1G93A mice receiving Immunocal®. (A) Mean GSH and GSSG concentrations and GSH/GSSG ratios from the lumbar spinal cord of end-stage trial animals determined using HPLC-EC detection, n = 17. * indicates p < 0.05; ns indicates no significant difference. (B) Representative HPLC-EC chromatograms from the lumbar spinal cord of end-stage animals; labeled peaks indicate GSH and GSSG oxidizing at 600 mV. Full article ">Figure 5
Spinal cord mitochondrial GSH levels and mitochondrial GSH transport are significantly diminished in hSOD1G93A mice. (A) Mitochondria were isolated from NonTG and hSOD1G93A mice at onset (~90 days old) and end-stage (~120 days old) from lumbar spinal cord and whole cortex, and total GSH was measured. All measurements were normalized to protein and represented as a percent of NonTG. *** indicates p < 0.001; NS indicates no significant difference, as determined by an unpaired Student’s t-test, n = 4. Error bars indicate SEM. (B) Mitochondria were isolated from lumbar spinal cord and cortex of end-stage (~120 days old) hSOD1G93A and age-matched NonTG mice, as described in (A). Isolated mitochondria were incubated with 2 mM GSH at 37 °C, 300 rpm for 4 h, after which mitochondria were washed 3× and total GSH was measured. All measurements were normalized to protein and represented as μmoles GSH/mg of mitochondrial protein loaded per hour. * indicates p < 0.05; NS indicates no significant difference, as determined by a paired Student’s t-test, n = 7. Error bars indicated SEM. (C) Mitochondria were isolated from lumbar spinal cord as described in (A) from untreated end-stage (~120 days old) hSOD1G93A mice, hSOD1G93A mice treated with Immunocal® (hSOD1G93A + ICAL) and age-matched NonTG mice. Total GSH was measured. All measurements of total GSH are normalized to protein and represented as nmols/mg of protein. ** indicates p < 0.01; NS indicates no significant difference, as determined using a one-way ANOVA with a post hoc Tukey’s test, n = 4. Error bars indicate SEM. Full article ">Figure 6
Treatment with Immunocal® an riluzole significantly delays disease onset and extends survival in hSOD1G93A mice. (A) hSOD1G93A mice receiving riluzole beginning at 60 days of age (pre-symptomatically) show no delay in disease onset and clinical decline compared to untreated mutant mice (n = 8). hSOD1G93A mice receiving riluzole in addition to Immunocal® showed a significant delay in disease onset and clinical decline compared to untreated mutant mice (p < 0.001; n = 10). Onset curves were compared pair-wise using the Gehan–Breslow–Wilcoxon test. (B) hSOD1G93A mice receiving riluzole beginning at 60 days of age (pre-symptomatically) showed a significant extension in survival compared to untreated mutant mice (n = 7; p < 0.05). Similarly, hSOD1G93A mice receiving riluzole in addition to Immunocal® showed a significant extension in survival compared to untreated mutant mice (p < 0.05; n = 8). Survival curves were compared pair-wise using the Gehan–Breslow–Wilcoxon test. Full article ">Figure 7
Treatment with Immunocal® and riluzole diminishes the decline in grip strength in hSOD1G93A mice. (A) The PaGE hanging wire test expressed as latency to fall at indicated ages (n = 8); (B) body weight of wild-type and hSOD1G93A mice expressed as percent of peak body weight. All data are represented as the mean ± SEM. *** indicates p < 0.001 compared to NonTG; ** indicates p < 0.01 compared to NonTG; * indicates p < 0.05 compared to NonTG; †† indicates p < 0.01 compared to untreated hSOD1G93A mice; and † indicates p < 0.05 compared to untreated hSOD1G93A mice (one-way ANOVA with a post hoc Tukey’s test conducted for each time point). Full article ">

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Open AccessArticle

Rosmarinic Acid, a New Polyphenol from Baccaurea ramiflora Lour. Leaf: A Probable Compound for Its Anti-Inflammatory Activity

by Talambedu Usha, Sushil Kumar Middha, Malay Bhattacharya, Prakash Lokesh and Arvind Kumar Goyal

Antioxidants 2014, 3(4), 830-842; https://doi.org/10.3390/antiox3040830 - 3 Dec 2014

Cited by 44 | Viewed by 10727

Abstract

Despite several pharmacological applications of Baccaurea ramiflora Lour., studies on the influence of its polyphenol content on pharmacological activity such as anti-inflammatory properties have been scarce. Here we evaluated in vitro antioxidant activity, poyphenolics by HPLC and the anti-inflammatory potential of the methanolic [...] Read more.

Despite several pharmacological applications of Baccaurea ramiflora Lour., studies on the influence of its polyphenol content on pharmacological activity such as anti-inflammatory properties have been scarce. Here we evaluated in vitro antioxidant activity, poyphenolics by HPLC and the anti-inflammatory potential of the methanolic leaf extract of Baccaurea ramiflora (BME) and its protective effects in carrageenan-induced paw edema model of inflammation in rats. The BME extract contained 79.06 ± 0.03 mg gallic acid equivalent (GAE)/g total polyphenols, 28.80 ± 0.01 mg quercetin equivalent (QE)/g flavonoid and 29.42 ± 0.01 μg cathechin equivalent/g proanthocyanidin respectively and rosmarinic acid (8 mg/kg) as a main component was identified by HPLC. Results demonstrate that administration of BME at the dose of 200 mg/kg can reduce paw edema by over 63%, and it exhibits a dose-response effect. Depending on concentration, the extract exerted scavenging activity on DPPH radical (IC₅₀ 36.4 μg/mL), significantly inhibited IL-1β (4.4 pg/mg protein) and TNF-α (0.21 ng/μg protein). Therefore, we conclude BME causes a substantial reduction of inflammation in in vivo models. We propose that rosmarinic acid and similar phenolic compounds may be useful in the therapy of inflammation-related injuries. Full article

(This article belongs to the Special Issue Analytical Determination of Polyphenols)

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612 KiB

Open AccessArticle

An Optimised Aqueous Extract of Phenolic Compounds from Bitter Melon with High Antioxidant Capacity

by Sing Pei Tan, Costas Stathopoulos, Sophie Parks and Paul Roach

Antioxidants 2014, 3(4), 814-829; https://doi.org/10.3390/antiox3040814 - 2 Dec 2014

Cited by 60 | Viewed by 12078

Abstract

Bitter melon (Momordica charantia L.) is a tropical fruit claimed to have medicinal properties associated with its content of phenolic compounds (TPC). The aim of the study was to compare water with several organic solvents (acetone, butanol, methanol and 80% ethanol) for [...] Read more.

Bitter melon (Momordica charantia L.) is a tropical fruit claimed to have medicinal properties associated with its content of phenolic compounds (TPC). The aim of the study was to compare water with several organic solvents (acetone, butanol, methanol and 80% ethanol) for its efficiency at extracting the TPC from freeze-dried bitter melon powder. The TPC of the extracts was measured using the Folin-Ciocalteu reagent and their antioxidant capacity (AC) was evaluated using three assays. Before optimisation, the TPC and AC of the aqueous extract were 63% and 20% lower, respectively, than for the best organic solvent, 80% ethanol. However, after optimising for temperature (80 °C), time (5 min), water-to-powder ratio (40:1 mL/g), particle size (1 mm) and the number of extractions of the same sample (1×), the TPC and the AC of the aqueous extract were equal or higher than for 80% ethanol. Furthermore, less solvent (40 mL water/g) and less time (5 min) were needed than was used for the 80% ethanol extract (100 mL/g for 1 h). Therefore, this study provides evidence to recommend the use of water as the solvent of choice for the extraction of the phenolic compounds and their associated antioxidant activities from bitter melon. Full article

(This article belongs to the Special Issue Analytical Determination of Polyphenols)

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Graphical abstract

Graphical abstract
Full article ">Figure 1
Diagram for the experimental design. Initially, the total phenolic content (TPC) and antioxidant capacity (AC) of the extracts of freeze-dried bitter melon powder obtained with five different solvents, including water, were compared. The aqueous extraction conditions were then optimised in terms of TPC and AC and compared to the 80% ethanol extract, which had the highest values in the initial solvent screening experiment. Full article ">Figure 2
Total phenolic content of bitter melon extracts obtained with five solvents. Values are means ± standard deviations (n = 3) and those not sharing a superscript letter are significantly different (p < 0.05) from each other. Full article ">Figure 3
The 2,2′-azinobis-(3-ethylbenzothiozoline-6-sulfonic acid (ABTS), 2,2′-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays were used to determine the antioxidant capacity. Values are means ± standard deviations (n = 3) and those not sharing a superscript letter are significantly different (p < 0.05) from each other. Full article ">Figure 4
The extraction efficiency for phenolic compounds from bitter melon using water. The aqueous extraction was optimised using one-variable-at-a-time method and each variable was tested in sequential order: (A) temperature; (B) time; (C) water-to-powder ratio; (D) powder particle size and (E) number of times the same sample is extracted. The powder particle size categories were: (1) <0.25, (2) 0.25–0.05, (3) 0.5–1.0, (4) 1.0–2.0, (5) 2.0–2.8 and (6) >2.8 mm. The extraction efficiency was relative to the 80% ethanol extract and data are means ± standard deviations (n = 3) and those not sharing a letter are significantly different (p < 0.05) from each other. * This value is also significantly different (p < 0.05) from the values obtained at 40 °C. Full article ">Figure 4 Cont.
The extraction efficiency for phenolic compounds from bitter melon using water. The aqueous extraction was optimised using one-variable-at-a-time method and each variable was tested in sequential order: (A) temperature; (B) time; (C) water-to-powder ratio; (D) powder particle size and (E) number of times the same sample is extracted. The powder particle size categories were: (1) <0.25, (2) 0.25–0.05, (3) 0.5–1.0, (4) 1.0–2.0, (5) 2.0–2.8 and (6) >2.8 mm. The extraction efficiency was relative to the 80% ethanol extract and data are means ± standard deviations (n = 3) and those not sharing a letter are significantly different (p < 0.05) from each other. * This value is also significantly different (p < 0.05) from the values obtained at 40 °C. Full article ">Figure 5
The extraction efficiency for antioxidant capacity from bitter melon using water. The aqueous extraction was optimised using one-variable-at-a-time method and each variable was tested in sequential order: (A) temperature; (B) time; (C) water-to-powder ratio; (D) powder particle size and (E) number of times the same sample is extracted. The powder particle size categories were: (1) <0.25, (2) 0.25–0.05, (3) 0.5–1.0, (4) 1.0–2.0, (5) 2.0–2.8 and (6) >2.8 mm. The extraction efficiency was relative to the 80% ethanol extract and data are means ± standard deviations (n = 3) and those not sharing a letter are significantly different (p < 0.05) from each other. Full article ">Figure 5 Cont.
The extraction efficiency for antioxidant capacity from bitter melon using water. The aqueous extraction was optimised using one-variable-at-a-time method and each variable was tested in sequential order: (A) temperature; (B) time; (C) water-to-powder ratio; (D) powder particle size and (E) number of times the same sample is extracted. The powder particle size categories were: (1) <0.25, (2) 0.25–0.05, (3) 0.5–1.0, (4) 1.0–2.0, (5) 2.0–2.8 and (6) >2.8 mm. The extraction efficiency was relative to the 80% ethanol extract and data are means ± standard deviations (n = 3) and those not sharing a letter are significantly different (p < 0.05) from each other. Full article ">

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Open AccessArticle

Antioxidant Potential of Plumieride against CCl₄-Induced Peroxidative Damage in Rats

by Dharmendra Singh, Priya Vrat Arya, Ashutosh Sharma, Ved Prakash Aggarwal, Mahabeer Prasad Dobhal and Radhey Shyam Gupta

Antioxidants 2014, 3(4), 798-813; https://doi.org/10.3390/antiox3040798 - 27 Nov 2014

Cited by 13 | Viewed by 6720

Abstract

In search of a new potent as an antioxidant from natural sources, plumieride—an iridoid isolated from the methanol extract of the bark of Plumeria bicolor (family Apocynaceae) was evaluated for its antioxidant potential against CCl₄-induced peroxidative damage in liver of rats. [...] Read more.

In search of a new potent as an antioxidant from natural sources, plumieride—an iridoid isolated from the methanol extract of the bark of Plumeria bicolor (family Apocynaceae) was evaluated for its antioxidant potential against CCl₄-induced peroxidative damage in liver of rats. The antioxidant potential was evaluated by using hepatic tissue for SOD (superoxide dismutase), CAT (catalase), GSH (reduced glutathione), GPx (glutathione peroxidase), GR (glutathione reductase) and LPO (lipid peroxidation) alongwith the concomitant blood serum for AST & ALT (aspartate and alanine transaminases), GGT (gamma glutamyl transpeptidase), ALP (alkaline phosphatase), total bilirubin and total protein contents. All the biochemical parameters were significantly (p ≤ 0.001) altered by CCl₄ (0.3 mL/kg body weight/twice a week, intra-peritoneally for 30 days). Simultaneously, oral treatment with plumieride (5, 10 and 20 mg/kg body weight/day for 30 days), restored all the parameters towards a normal level, remarkably. The histological findings of liver sections further corroborated the antioxidant potential of plumieride compared with standard drug-silymarin. In conclusion, plumieride consists of sugar molecules, which have alcoholic groups. Therefore, the alcoholic groups of sugar increase its antioxidant potential through intermolecular hydrogen bonding along with the thiol(SH) group of non-protein thiols and enzymes resulting in the restoration of the antioxidant system. Therefore, it might be considered a natural antioxidant against peroxidative damage in rats. Full article

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Chemical structure of plumieride. Full article ">Figure 2
Photomicrograph of control rat liver section showing well brought central vein, hepatic cells with preserved cytoplasm and prominent nucleus at H & E × 10. Full article ">Figure 3
Photomicrograph of rat liver section with CCl4 treatment showing ballooning degeneration and distended portal vein, mild periportal fibrosis and necrosis at H & E × 100. Full article ">Figure 4
Photomicrograph of rat liver section of CCl4 + Plumieride (5 mg/kg body weight), showing reasonable reduction in necrosis, fatty changes along with cytoplasmic clearing at H & E × 100. Full article ">Figure 5
Photomicrograph of rat liver section of CCl4 + Plumieride (10 mg/kg body weight), reflecting considerable reduction in necrosis, fatty changes and exhibiting cytoplasmic clearing at H & E × 100. Full article ">Figure 6
Photomicrograph of rat liver section of CCl4 + Plumieride (20 mg/kg body weight), showing moderately brought central vein, hepatic cells with preserved cytoplasm and prominent nucleus at H & E × 100. Full article ">Figure 7
Photomicrograph of rat liver section of CCl4 + Silymarin (20 mg/kg body weight), showing moderately brought central vein, hepatic cells along with preserved cytoplasm and prominent nucleus at H & E × 100. Full article ">

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Open AccessReview

Role of Oxidative Stress in HIV-1-Associated Neurocognitive Disorder and Protection by Gene Delivery of Antioxidant Enzymes

by Jean-Pierre Louboutin and David Strayer

Antioxidants 2014, 3(4), 770-797; https://doi.org/10.3390/antiox3040770 - 18 Nov 2014

Cited by 30 | Viewed by 8067

Abstract

HIV encephalopathy covers a range of HIV-1-related brain dysfunction. In the Central Nervous System (CNS), it is largely impervious to Highly Active AntiRetroviral Therapy (HAART). As survival with chronic HIV-1 infection improves, the number of people harboring the virus in their CNS increases. [...] Read more.

HIV encephalopathy covers a range of HIV-1-related brain dysfunction. In the Central Nervous System (CNS), it is largely impervious to Highly Active AntiRetroviral Therapy (HAART). As survival with chronic HIV-1 infection improves, the number of people harboring the virus in their CNS increases. Neurodegenerative and neuroinflammatory changes may continue despite the use of HAART. Neurons themselves are rarely infected by HIV-1, but HIV-1 infects resident microglia, periventricular macrophages, leading to increased production of cytokines and to release of HIV-1 proteins, the most likely neurotoxins, among which are the envelope glycoprotein gp120 and HIV-1 trans-acting protein Tat. Gp120 and Tat induce oxidative stress in the brain, leading to neuronal apoptosis/death. We review here the role of oxidative stress in animal models of HIV-1 Associated Neurocognitive Disorder (HAND) and in patients with HAND. Different therapeutic approaches, including clinical trials, have been used to mitigate oxidative stress in HAND. We used SV40 vectors for gene delivery of antioxidant enzymes, Cu/Zn superoxide dismutase (SOD1), or glutathione peroxidase (GPx1) into the rat caudate putamen (CP). Intracerebral injection of SV (SOD1) or SV (GPx1) protects neurons from apoptosis caused by subsequent inoculation of gp120 and Tat at the same location. Vector administration into the lateral ventricle or cisterna magna protects from intra-CP gp120-induced neurotoxicity comparably to intra-CP vector administration. These models should provide a better understanding of the pathogenesis of HIV-1 in the brain as well as offer new therapeutic avenues. Full article

(This article belongs to the Special Issue Oxidative Stress and Neurodegenerative Diseases)

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Open AccessArticle

Antioxidant Content, Antioxidant Activity, and Antibacterial Activity of Five Plants from the Commelinaceae Family

by Joash Ban Lee Tan, Wei Jin Yap, Shen Yeng Tan, Yau Yan Lim and Sui Mae Lee

Antioxidants 2014, 3(4), 758-769; https://doi.org/10.3390/antiox3040758 - 17 Nov 2014

Cited by 42 | Viewed by 14499

Abstract

Commelinaceae is a family of herbaceous flowering plants with many species used in ethnobotany, particularly in South America. However, thus far reports of their bioactivity are few and far between. The primary aim of this study was to quantify the antioxidant and antibacterial [...] Read more.

Commelinaceae is a family of herbaceous flowering plants with many species used in ethnobotany, particularly in South America. However, thus far reports of their bioactivity are few and far between. The primary aim of this study was to quantify the antioxidant and antibacterial activity of five Commelinaceae methanolic leaf extracts. The antioxidant content was evaluated by the total phenolic content (TPC), total tannin content (TTC), and total flavonoid content (TFC) assays. The antioxidant activities measured were DPPH free radical scavenging (FRS), ferric reducing power (FRP), and ferrous ion chelating (FIC); of the five plants, the methanolic leaf extract of Tradescantia zebrina showed the highest antioxidant content and activity, and exhibited antibacterial activity against six species of Gram-positive and two species of Gram-negative bacteria in a range of 5–10 mg/mL based on the broth microdilution method. Full article

(This article belongs to the Special Issue Natural Products as Antioxidants)

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611 KiB

Open AccessArticle

Evaluation of Antioxidant Activity, Total Flavonoids, Tannins and Phenolic Compounds in Psychotria Leaf Extracts

by Anelise Samara Nazari Formagio, Carla Roberta Ferreira Volobuff, Matheus Santiago, Claudia Andrea Lima Cardoso, Maria Do Carmo Vieira and Zefa Valdevina Pereira

Antioxidants 2014, 3(4), 745-757; https://doi.org/10.3390/antiox3040745 - 10 Nov 2014

Cited by 119 | Viewed by 11900

Abstract

The antioxidant activity of Psychotria carthagenensis, P. leiocarpa, P. capillacea and P. deflexa (Rubiaceae) extracts were investigated, and the concentrations of total phenolics, flavonoids, condensed tannins and flavonols were determined. The chemical compositions of the extracts were investigated using the high [...] Read more.

The antioxidant activity of Psychotria carthagenensis, P. leiocarpa, P. capillacea and P. deflexa (Rubiaceae) extracts were investigated, and the concentrations of total phenolics, flavonoids, condensed tannins and flavonols were determined. The chemical compositions of the extracts were investigated using the high performance liquid chromatography (HPLC/PAD) method. We used 1,1-diphenyl-1-picrylhydrazyl free radical (DPPH), β-Carotene bleaching and 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cations to determine antioxidant activity. The ability to scavenge radical was measured in these experiments by the discoloration of the solution. Concentrations of constituents were measured spectrophotometrically. P. carthagenensis and P. capillacea exhibited the highest antioxidant activity, in the DPPH test, β-carotene bleaching and ABTS system. The highest phenolic, flavonoid, condensed tannin and flavonol concentration was found in P. carthagenensis and P. capillacea extracts. HPLC-PDA analysis of P. carthagenensis and P. capillacea revealed hydroxycinnamic acid (p-coumaric acid). This is the first report on the antioxidant properties and constituent analysis of these Psychotria extracts. Full article

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Open AccessArticle

Antioxidant and Anti-Inflammatory Properties of an Extract Rich in Polysaccharides of the Mushroom Polyporus dermoporus

by Celina Maria P. Guerra Dore, Monique Gabriela das Chagas F. Alves, Maria Da Glória L. Santos, Leonardo Augusto R. De Souza, Iuri Goulart Baseia and Edda Lisboa Leite

Antioxidants 2014, 3(4), 730-744; https://doi.org/10.3390/antiox3040730 - 4 Nov 2014

Cited by 42 | Viewed by 7596

Abstract

Polyporus dermoporus mushroom, native to Brazil, is produced under natural conditions in the unexplored reserve of Mata da Estrela-Rio Grande do Norte-RN. These mushrooms were delipidated with chloroform:methanol (2:1 v/v), extracted with water at 100 °C, and fractionated with ethanol (one and three [...] Read more.

Polyporus dermoporus mushroom, native to Brazil, is produced under natural conditions in the unexplored reserve of Mata da Estrela-Rio Grande do Norte-RN. These mushrooms were delipidated with chloroform:methanol (2:1 v/v), extracted with water at 100 °C, and fractionated with ethanol (one and three volumes) and then centrifuged. The ethanol precipitation showed a high total sugar level of 64.8% and 1% of protein. This precipitate contained a high glucan level, characterized by chemical methods and by NMR of ¹³C and ¹H and spectroscopy. The ¹³C NMR spectrum of these mushroom extracts showed the presence of β-glucose by a signal at 103.25 ppm. Studies with these glucans were made to elucidate antioxidant and anti-inflammatory activities. This extract of glucans inhibited the lipid peroxidation (42.9%) and superoxide radicals (83.3%) at 67 μg/mL. However, the inhibition of hydroxyl radical by the extract of this mushroom was 96% at 267 μg/mL. The action of this extract on induced pleurisy showed a 92.5% and 68.7% reduction in polymorphonuclears cells and nitric oxide, respectively, at 30 mg/kg. The glucans reduced the croton oil-induced ear edema by 65.6% at 30 mg/kg. Full article

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1 H NMR spectroscopy of Polyporus dermoporus glucan protein. Full article ">Figure 2
13 C NMR spectroscopy of Polyporus dermoporus glucan-protein. Full article ">Figure 3
Anti-inflammatory effect of P. dermoporus extract (PD) on carrageenan-induced pleurisy. The number of pleural exudate leukocytes in carrageenan-induced Wistar rats. The experimental animals were treated with P. dermoporus extract at 10 mg/kg (PD 10), 30 mg/kg (PD 30) and 50 mg/kg (PD 50). Data obtained from animal experiments are expressed as the mean ± SD. The differences between treatment and control were tested by ANOVA. A value of (***) p < 0.001 was considered statistically significant. Full article ">Figure 4
Effect of P. dermoporus polysaccharides on NO production from the pleural exudate of Wistar rats with carrageenan-induced pleurisy. The animals were treated with 10 mg/kg (PD 10), 30 mg/kg (PD 30) and 50 mg/kg (PD 50) of P. dermoporus extract. Control: Wistar rats with carrageenan-induced pleurisy. Data obtained from animal experiments (n = 7) are expressed as the mean ± SD. The differences between the treatment and control were tested using ANOVA. A value of (***) p < 0.001 was considered statistically significant. Full article ">Figure 5
The effect of P. dermoporus polysaccharides on the croton oil-induced ear edema assay in BALBc mice. The animals were treated with 10 mg/kg (PD 10), 30 mg/kg (PD 30) and 50 mg/kg (PD 50) of P. dermoporus polysaccharides. Data obtained from animal experiments are expressed as the mean ± SD. The differences between treatment and control were tested by ANOVA. A value of (***) p < 0.001 was considered statistically significant. Full article ">Figure 6
Histological analysis of ear edema with H & E stain 200× from animals submitted to the croton oil-induced ear edema test and treated with P. dermoporus polysaccharides: (A) positive control (croton oil); (B) negative control (saline); (C) P. dermoporus polysaccharides at 10 mg/kg (PD 10); (D) animals treated with 30 mg/kg (PD 30); (E) animals treated with 50 mg/kg (PD 50). Full article ">

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Open AccessArticle

Antioxidant Capacity, Cytotoxicity and Antimycobacterial Activity of Madeira Archipelago Endemic Helichrysum Dietary and Medicinal Plants

by Sandra C. Gouveia-Figueira, Carla A. Gouveia, Maria J. Carvalho, Ana I. Rodrigues, Malin L. Nording and Paula C. Castilho

Antioxidants 2014, 3(4), 713-729; https://doi.org/10.3390/antiox3040713 - 31 Oct 2014

Cited by 10 | Viewed by 6896

Abstract

The potential bioactivity of dietary and medicinal endemic Helichrysum plants from Madeira Archipelago was explored, for the first time, in order to supply new information for the general consumer. In vitro antioxidant properties were investigated using DPPH, ABTS^•+, FRAP and β-Carotene [...] Read more.

The potential bioactivity of dietary and medicinal endemic Helichrysum plants from Madeira Archipelago was explored, for the first time, in order to supply new information for the general consumer. In vitro antioxidant properties were investigated using DPPH, ABTS^•+, FRAP and β-Carotene assays, and the total phenolic content (TPC) and total flavonoid content (TFC) were also determined. Although the results generally showed a large variation among the three analyzed plants, the methanolic extracts showed the highest antioxidant capacity. Exception is made for H. devium n-hexane extract that showed good radical scavenger capacity associated to compounds with good reducing properties. In the Artemia salina toxicity assay and antimycobaterial activity, H. devium was the most potent plant with the lowest LD₅₀ at 216.7 ± 10.4 and MIC ≤ 50 μg·mL⁻¹. Chemometric evaluation (Principal Component Analysis—PCA) showed close interdependence between the ABTS, TPC and TFC methods and allowed to group H. devium samples. Full article

(This article belongs to the Special Issue Natural Products as Antioxidants)

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2379 KiB

Open AccessArticle

Optimization of the Aqueous Extraction of Phenolic Compounds from Olive Leaves

by Chloe D. Goldsmith, Quan V. Vuong, Costas E. Stathopoulos, Paul D. Roach and Christopher J. Scarlett

Antioxidants 2014, 3(4), 700-712; https://doi.org/10.3390/antiox3040700 - 23 Oct 2014

Cited by 51 | Viewed by 8616

Abstract

Olive leaves are an agricultural waste of the olive-oil industry representing up to 10% of the dry weight arriving at olive mills. Disposal of this waste adds additional expense to farmers. Olive leaves have been shown to have a high concentration of phenolic [...] Read more.

Olive leaves are an agricultural waste of the olive-oil industry representing up to 10% of the dry weight arriving at olive mills. Disposal of this waste adds additional expense to farmers. Olive leaves have been shown to have a high concentration of phenolic compounds. In an attempt to utilize this waste product for phenolic compounds, we optimized their extraction using water—a “green” extraction solvent that has not yet been investigated for this purpose. Experiments were carried out according to a Box Behnken design, and the best possible combination of temperature, extraction time and sample-to-solvent ratio for the extraction of phenolic compounds with a high antioxidant activity was obtained using RSM; the optimal conditions for the highest yield of phenolic compounds was 90 °C for 70 min at a sample-to-solvent ratio of 1:100 g/mL; however, at 1:60 g/mL, we retained 80% of the total phenolic compounds and maximized antioxidant capacity. Therefore the sample-to-solvent ratio of 1:60 was chosen as optimal and used for further validation. The validation test fell inside the confidence range indicated by the RSM output; hence, the statistical model was trusted. The proposed method is inexpensive, easily up-scaled to industry and shows potential as an additional source of income for olive growers. Full article

(This article belongs to the Special Issue Natural Products as Antioxidants)

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Open AccessArticle

Modelling Extraction of White Tea Polyphenols: The Influence of Temperature and Ethanol Concentration

by Sara Peiró, Michael H. Gordon, Mónica Blanco, Francisca Pérez-Llamas, Francisco Segovia and María Pilar Almajano

Antioxidants 2014, 3(4), 684-699; https://doi.org/10.3390/antiox3040684 - 21 Oct 2014

Cited by 14 | Viewed by 9028

Abstract

The optimization of the extraction of natural antioxidants from white tea has fostered intensive research. This study has investigated the effects of ethanol-water mixtures, temperature and time on the extraction of polyphenols and antioxidant components from white tea. The response surface methodology was [...] Read more.

The optimization of the extraction of natural antioxidants from white tea has fostered intensive research. This study has investigated the effects of ethanol-water mixtures, temperature and time on the extraction of polyphenols and antioxidant components from white tea. The response surface methodology was applied to identify the best extraction conditions. The best conditions to maximize the extraction of total polyphenols were: ethanol, 50%, for 47.5 min. Although the yield of polyphenols was optimal at 65 °C, the maximum antioxidant capacity was achieved with an extraction temperature of 90 °C. This study has identified the optimal conditions for the extraction of tea liquor with the best antioxidant properties. Epigallocatechin gallate, epicatechin gallate, epigallocatechin and epicatechin were extracted from white tea at concentrations up to 29.6 ± 10.6, 5.40 ± 2.09, 5.04 ± 0.20 and 2.48 ± 1.10 mg/100 g. Full article

(This article belongs to the Special Issue Natural Products as Antioxidants)

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Open AccessArticle

Analysis of Phenolic and Flavonoid Contents, and the Anti-Oxidative Potential and Lipid Peroxidation Inhibitory Activity of Methanolic Extract of Carissa opaca Roots and Its Fractions in Different Solvents

by Dildar Ahmed, Khaizran Fatima and Ramsha Saeed

Antioxidants 2014, 3(4), 671-683; https://doi.org/10.3390/antiox3040671 - 20 Oct 2014

Cited by 40 | Viewed by 10920

Abstract

The objective of the present work was to investigate the anti-oxidative potential of methanolic extract of Carissa opaca roots and its fractions in solvents of different polarities. Total phenolic (TPC) and flavonoid (TFC) contents of methanolic extract were 211.95 ± 0.78 μg/mL gallic [...] Read more.

The objective of the present work was to investigate the anti-oxidative potential of methanolic extract of Carissa opaca roots and its fractions in solvents of different polarities. Total phenolic (TPC) and flavonoid (TFC) contents of methanolic extract were 211.95 ± 0.78 μg/mL gallic acid equivalents (GAE) and 8.35 ± 0.21 μg/mL rutin equivalents (RE), respectively. Ethyl acetate contained the highest amounts of both (TFC, 11.8 ± 0.28 RE; TPC, 342.80 ± 0.42 GAE) followed by chloroform fraction (TFC, 7.50 ± 0.14 RE; TPC, 275.85 ± 0.50 GAE). Extract and fractions displayed remarkable DPPH radical scavenging activity. EC₅₀ values of methanolic extract was 0.88 mg/mL, while that of hexane, chloroform, ethyl acetate, n-butanolic and aqueous fractions were 0.58, 0.38, 0.29, 0.36 and 5.83 mg/mL, respectively, ethyl acetate fraction being most potent. The ethyl acetate fraction also showed the highest activity in terms of reducing power, phosphomolybdate and ABTS assays. All the fractions showed fairly good lipid peroxidation inhibitory activity, which remained almost constant over three days. Based on the results it can be concluded that roots of Carissa opaca contains phytochemicals with exploitable antioxidant, free radical scavenging, and lipid peroxidation inhibitory potential. Full article

(This article belongs to the Special Issue Natural Products as Antioxidants)

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Percent free radical scavenging activity of methanolic extract of Carissa opaca roots and its fractions in ABTS assay (n = 3); Concentration of each sample was 1 mg/mL. Full article ">Figure 2
ABTS radical scavenging activity methanolic extract of Carissa opaca roots and its factions in terms of TEAC (Trolox equivalent antioxidant capacity) (n = 3). Full article ">Figure 3
Antioxidant activities as per reducing power assay (mean absorbance at 700 nm) of methanolic extract of Carissa opaca roots and its fractions in various solvents (n = 3). Full article ">Figure 4
Antioxidant capacity of methanolic extract of Carissa opaca roots and its fractions in various solvents as per phosphomolybdate assay in units of μg/mL of ascorbic acid equivalents (AAE). Full article ">Figure 5
Lipid peroxidation inhibitory activity of methanolic extract of Carissa opaca roots and its fractions in various solvents and BHA (n = 3). Full article ">

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Open AccessReview

Flavonoids Affect Host-Microbiota Crosstalk through TLR Modulation

by Francisco J. Pérez-Cano, Malen Massot-Cladera, Maria J. Rodríguez-Lagunas and Margarida Castell

Antioxidants 2014, 3(4), 649-670; https://doi.org/10.3390/antiox3040649 - 17 Oct 2014

Cited by 45 | Viewed by 13178

Abstract

Interaction between host cells and microbes is known as crosstalk. Among other mechanisms, this takes place when certain molecules of the micro-organisms are recognized by the toll-like receptors (TLRs) in the body cells, mainly in the intestinal epithelial cells and in the immune [...] Read more.

Interaction between host cells and microbes is known as crosstalk. Among other mechanisms, this takes place when certain molecules of the micro-organisms are recognized by the toll-like receptors (TLRs) in the body cells, mainly in the intestinal epithelial cells and in the immune cells. TLRs belong to the pattern-recognition receptors and represent the first line of defense against pathogens, playing a pivotal role in both innate and adaptive immunity. Dysregulation in the activity of such receptors can lead to the development of chronic and severe inflammation as well as immunological disorders. Among components present in the diet, flavonoids have been suggested as antioxidant dietary factors able to modulate TLR-mediated signaling pathways. This review focuses on the molecular targets involved in the modulatory action of flavonoids on TLR-mediated signaling pathways, providing an overview of the mechanisms involved in such action. Particular flavonoids have been able to modify the composition of the microbiota, to modulate TLR gene and protein expression, and to regulate the downstream signaling molecules involved in the TLR pathway. These synergistic mechanisms suggest the role of some flavonoids in the preventive effect on certain chronic diseases. Full article

(This article belongs to the Special Issue Interactions between Dietary Flavonoids and Gut Microbiota: Functional Outcomes)

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Chemical structure and representative compounds from the main families of flavonoids. Full article ">Figure 2
Overview of the mechanisms involved in the regulation of microbiota-host crosstalk by flavonoids. They can act at three different levels by modulating: (1) microbiota composition, by means of directly (flavonoid) or indirectly (metabolite) affecting the growth; (2) Toll-like receptor (TLR) activation, by means of acting on the receptor and its adaptor proteins; (3) signal transduction, by means of interfering with upstream and downstream kinases as well as the transcription factors involved in the inflammatory and immune response activation. Full article ">Figure 3
Summary of the number of treatments using beverages (cocoa, tea and wine), fruits or vegetables (soy, pomegranate, grapes, berries and apples) rich in flavonoids and their impact on bacterial growth. There is a high number of studies with flavonoids (in vitro and in vivo) showing both antimicrobial activity (left) and growth-promoting effects (right) on the more prevalent bacterial groups. Full article ">Figure 4
Signal transduction molecules affected by the flavonoids modulatory action on TLR activation. Both, the MyD88 dependent (left) and independent (right) pathways are modulated by the effect of several flavonoids on targets from different upstream (TLR expression and activation; adaptors modulation) and downstream levels (kinases and transcription factors). Black arrows indicate stimulation of the pathway and red arrows indicate inhibition of the pathway. In brackets there are the references cited in the text. Full article ">

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Open AccessReview

Assessing Antioxidant Capacity in Brain Tissue: Methodologies and Limitations in Neuroprotective Strategies

by Jennifer E. Slemmer and John T. Weber

Antioxidants 2014, 3(4), 636-648; https://doi.org/10.3390/antiox3040636 - 13 Oct 2014

Cited by 13 | Viewed by 6880

Abstract

The number of putative neuroprotective compounds with antioxidant activity described in the literature continues to grow. Although these compounds are validated using a variety of in vivo and in vitro techniques, they are often evaluated initially using in vitro cell culture techniques in [...] Read more.

The number of putative neuroprotective compounds with antioxidant activity described in the literature continues to grow. Although these compounds are validated using a variety of in vivo and in vitro techniques, they are often evaluated initially using in vitro cell culture techniques in order to establish toxicity and effective concentrations. Both in vivo and in vitro methodologies have their respective advantages and disadvantages, including, but not limited to, cost, time, use of resources and technical limitations. This review expands on the inherent benefits and drawbacks of in vitro and in vivo methods for assessing neuroprotection, especially in light of proper evaluation of compound efficacy and neural bioavailability. For example, in vivo studies can better evaluate the effects of protective compounds and/or its metabolites on various tissues, including the brain, in the whole animal, whereas in vitro studies can better discern the cellular and/or mechanistic effects of compounds. In particular, we aim to address the question of appropriate and accurate extrapolation of findings from in vitro experiment-where compounds are often directly applied to cellular extracts, potentially at higher concentrations than would ever cross the blood-brain barrier—to the more complex scenario of neuroprotection due to pharmacodynamics in vivo. Full article

(This article belongs to the Special Issue Oxidative Stress and Neurodegenerative Diseases)

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Antioxidants, Volume 3, Issue 4 (December 2014) – 15 articles , Pages 636-889

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