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Green Tea Extract Induces the Resistance of Caenorhabditis elegans against Oxidative Stress

Author(s):Sami Abbas -- Michael Wink
Journal: Antioxidants
Publisher:
Abstract
| Pages: 129-143
Epidemiological studies on the effects of green tea consumption (Camellia sinensis) have demonstrated a reduction for the risk of age-related diseases. The investigation of the in vivo and in vitroantioxidant properties of an aqueous extract of green tea (GTE) was the aim of the current study. 2,2-Diphenyl-1-picrylhydrazyl (DPPH•) and superoxide anion radical (O2•−) assays were used to estimate the GTE antioxidant activity. To investigate the protective effects of GTE against oxidative stress, wild-type N2 and transgenic strains (TJ374, hsp-16.2/GFP) of the model organism, Caenorhabditis elegans (C. elegans), were chosen. In the current study, the following catechins were identified by LC/ESI-MS: catechin, epicatechin, epicatechin gallate, gallocatechin, epigallocatechin and epigallocatechin gallate. GTE exhibited a free radical scavenging activity of DPPH• and O2•− with IC50 8.37 and 91.34 µg/mL, respectively. In the C. elegans strain (TJ374, hsp-16.2/GFP), the expression of hsp-16.2/GFP was induced by a nonlethal dose of juglone, and the fluorescence density of hsp-16.2/GFP was measured. The hsp-16.2/GFP was reduced by 68.43% in the worms pretreated with 100 µg/mL GTE. N2 worms pretreated with 100 µg/mL GTE exhibited an increased survival rate of 48.31% after a lethal dose application of juglone. The results suggest that some green tea constituents are absorbed by the worms and play a substantial role to enhance oxidative stress resistance inC. elegans.

Dietary Polyphenols, Berries, and Age-Related Bone Loss: A Review Based on Human, Animal, and Cell Studies

Author(s):Patrice A. Hubert -- Sang Gil Lee -- Sun-Kyeong Lee -- Ock K. Chun
Journal: Antioxidants
Publisher:
Abstract
| Pages: 144-158
Bone loss during aging has become an increasing public health concern as average life expectancy has increased. One of the most prevalent forms of age-related bone disease today is osteoporosis in which the body slows down bone formation and existing bone is increasingly being resorbed by the body to maintain the calcium balance. Some causes of this bone loss can be attributed to dysregulation of osteoblast and osteoclast activity mediated by increased oxidative stress through the aging process. Due to certain serious adverse effects of the currently available therapeutic agents that limit their efficacy, complementary and alternative medicine (CAM) has garnered interest as a natural means for the prevention of this debilitating disease. Natural antioxidant supplementation, a type of CAM, has been researched to aid in reducing bone loss caused by oxidative stress. Naturally occurring polyphenols, such as anthocyanins rich in berries, are known to have anti-oxidative properties. Several studies have been reviewed to determine the impact polyphenol intake—particularly that of berries—has on bone health. Studies reveal a positive association of high berry intake and higher bone mass, implicating berries as possible inexpensive alternatives in reducing the risk of age related bone loss.

Identification of Phenolic Compounds and Evaluation of Antioxidant and Antimicrobial Properties of Euphorbia Tirucalli L

Author(s): Keline Medeiros de Araújo, Alessandro de Lima, Jurandy do N. Silva, Larissa L. Rodrigues, Adriany G. N. Amorim, Patrick V. Quelemes, Raimunda C. dos Santos, Jefferson A. Rocha, Éryka O. de And
Journal: Antioxidants
Publisher:
Abstract
| Pages: 159-175
Bioactive compounds extracted from natural sources can benefit human health. The aim of this work was to determine total phenolic content and antioxidant activity in extracts of Euphorbia tirucalli L. followed by identification and quantification of the phenolic compounds, as well as their antibacterial activities. Antioxidant activities were determined by DPPH and ABTS•+ assay. Identification of phenolic compounds was performed using high-performance liquid chromatography (HPLC), and antimicrobial activities were verified by agar dilution methods and MIC values. Total phenolic content ranged from 7.73 to 30.54 mg/100 g gallic acid equivalent. Extracts from dry plants showed higher antioxidant activities than those from fresh ones. The DPPH EC50 values were approximately 12.15 μg/mL and 16.59 μg/mL, respectively. Antioxidant activity measured by the ABTS method yielded values higher than 718.99 μM trolox/g for dry plants, while by the Rancimat® system yielded protection factors exceeding 1 for all extracts, comparable to synthetic BHT. Ferulic acid was the principal phenolic compound identified and quantified through HPLC-UV in all extracts. The extracts proved effective inhibitory potential for Staphylococcus epidermidis and Staphylococcus aureus. These results showed that extracts of Euphorbia tirucalli L. have excellent antioxidant capacity and moderate antimicrobial activity. These can be attributed to the high concentration of ferulic acid.

Effectiveness of α-, γ- and δ-Tocopherol in a CLA-Rich Oil

Author(s):Gloria Márquez-Ruiz -- María del Carmen García-Martínez -- Francisca Holgado -- Joaquín Velasco
Journal: Antioxidants
Publisher:
Abstract
| Pages: 176-188
Conjugated linoleic acid (CLA) is a mixture of positional and geometric isomers of octadecadienoic acid with conjugated double bounds. Positive health properties have been attributed to some isomers, such as anticarcinogenic activity, antiartherosclerotic effects and reduction of body fat gain. Hence, oils rich in CLA such as Tonalin® oil (TO), normally obtained through alkaline isomerization of safflower oil (SO), an oil rich in linoleic acid (LA), are currently used in functional foods. However, special care must be taken to protect them from oxidation to ensure the quality of the supplemented foods. The objective of this work was to evaluate the oxidation and effectiveness of different tocopherol homologues (α-, γ- and δ-), alone or in combination with synergists (ascorbyl palmitate and lecithin), in TO compared to SO at different conditions, ambient temperature (25 °C) and accelerated conditions in Rancimat (100 °C). The oils, the oils devoid of their antioxidants and the latter containing the antioxidants added were assayed. Results showed great differences between SO and TO in terms of formation of hydroperoxides and polymers and also in the effectiveness of tocopherols to delay oxidation. TO showed higher levels of polymerization and, in general, the effectiveness of tocopherol homologues, alone or in combination with synergists, was also lower in the TO.

Correction: Racchi, M.L. Antioxidant Defenses in Plants with Attention to Prunus and Citrus spp. Antioxidants 2013, 2, 340-369

Author(s):Milvia Luisa Racchi
Journal: Antioxidants
Publisher:
Abstract
| Pages: 189-189
 I have found two inadvertent errors in my review published in Antioxidants [1]. [...]

Effect of Drying Operating Conditions on Canola Oil Tocopherol Content

Author(s):Daniela Laoretani -- María Fernandez -- Guillermo Crapiste -- Susana Nolasco
Journal: Antioxidants
Publisher:
Abstract
| Pages: 190-199
The aim of this work was to evaluate two operating parameters of seed drying (temperature and initial moisture content) on the tocopherol content of canola oil. The raw material was characterized by moisture, oil, protein, crude fiber and ash content. Seeds at 13.6% and 22.7% moisture content (dry basis, db) were dried at temperatures in the range of 35–100 °C to a safe storage moisture of 7% db. Oil was extracted from each treated sample. The oil extracted from the samples dried at the extreme temperatures was analyzed by means of the acidity value, peroxide index and fatty acid composition, finding no significant differences among treatments or among untreated and treated samples. Tocopherol contents in the oils obtained for all the assayed temperatures were determined. Differences were found for the samples with 22.7% (db) initial moisture content. Except at 35 °C, temperature affected negatively the oil tocopherol content. However, when 13.6% (db) moisture seeds were processed, no significant differences were observed in the amount of this minor oil component among assays.

Antioxidant Activity of Grapevine Leaf Extracts against Oxidative Stress Induced by Carbon Tetrachloride in Cerebral Cortex, Hippocampus and Cerebellum of Rats

Author(s):Mariane Wohlenberg -- Daniela Almeida -- Liane Bokowski -- Niara Medeiros -- Fabiana Agostini -- Cláudia Funchal -- Caroline Dani
Journal: Antioxidants
Publisher:
Abstract
| Pages: 200-211
In recent years, it has become increasingly important to study the beneficial properties of derivatives of grapes and grapevine. The objective of this study was to determine the antioxidant activity of Vitis labruscaleaf extracts, comparing conventional and organic grapevines, in different brain areas of rats. We used male Wistar rats treated with grapevine leaf extracts for a period of 14 days, and on the 15th day, we administered in half of the rats, mineral oil and the other half, carbon tetrachloride (CCl4). The animals were euthanized by decapitation and the cerebral cortex, hippocampus and cerebellum were removed to assess oxidative stress parameters and the activity of antioxidant enzymes. Lipid peroxidation levels (TBARS) were unchanged. However, CCl4 induced oxidative damage to proteins in all tissues studied, and this injury was prevented by both extracts. Superoxide dismutase (SOD) activity was increased by CCl4 in the cerebral cortex and decreased in other tissues. However, CCl4 increased catalase (CAT) activity in the cerebellum and decreased it in the cerebral cortex. The SOD/CAT ratio was restored in the cerebellum by both extracts and only in the cerebral cortex by the organic extract.

Distribution and Antioxidant Efficiency of Resveratrol in Stripped Corn Oil Emulsions

Author(s):Sonia Losada-Barreiro -- Marlene Costa -- Carlos Bravo-Díaz -- Fátima Paiva-Martins
Journal: Antioxidants
Publisher:
Abstract
| Pages: 212-228
We investigated the effects of resveratrol (RES) on the oxidative stability of emulsions composed of stripped corn oil, acidic water and Tween 20 and determined its distribution in the intact emulsions by employing a well-established kinetic method. The distribution of RES is described by two partition constants, that between the oil-interfacial region, POI, and that between the aqueous and interfacial region, PWI. The partition constants, POI and PWI, are obtained in the intact emulsions from the variations of the observed rate constant, kobs, for the reaction between the hydrophobic 4-hexadecylbenzenediazonium ion and RES with the emulsifier volume fraction, ФI. The obtained POI and PWI values are quite high, PWI = 4374 and POI = 930, indicating that RES is primarily located in the interfacial region of the emulsions, %RESI > 90% at ФI = 0.005, increasing up to 99% at ФI = 0.04. The oxidative stability of the corn oil emulsions was determined by measuring the formation of conjugated dienes at a given time in the absence and in the presence of RES. The addition of RES did not improve their oxidative stability in spite that more than 90% of RES is located in the interfacial region of the emulsion, because of the very low radical scavenging activity of RES.

Antioxidant Activity and Thermal Stability of Oleuropein and Related Phenolic Compounds of Olive Leaf Extract after Separation and Concentration by Salting-Out-Assisted Cloud Point Extraction

Author(s):Konstantinos Stamatopoulos -- Evangelos Katsoyannos -- Arhontoula Chatzilazarou
Journal: Antioxidants
Publisher:
Abstract
| Pages: 229-244
A fast, clean, energy-saving, non-toxic method for the stabilization of the antioxidant activity and the improvement of the thermal stability of oleuropein and related phenolic compounds separated from olive leaf extract via salting-out-assisted cloud point extraction (CPE) was developed using Tween 80. The process was based on the decrease of the solubility of polyphenols and the lowering of the cloud point temperature of Tween 80 due to the presence of elevated amounts of sulfates (salting-out) and the separation from the bulk solution with centrifugation. The optimum conditions were chosen based on polyphenols recovery (%), phase volume ratio (Vs/Vw) and concentration factor (Fc). The maximum recovery of polyphenols was in total 95.9%; Vs/Vw was 0.075 and Fc was 15 at the following conditions: pH 2.6, ambient temperature (25 °C), 4% Tween 80 (w/v), 35% Na2SO4 (w/v) and a settling time of 5 min. The total recovery of oleuropein, hydroxytyrosol, luteolin-7-O-glucoside, verbascoside and apigenin-7-O-glucoside, at optimum conditions, was 99.8%, 93.0%, 87.6%, 99.3% and 100.0%, respectively. Polyphenolic compounds entrapped in the surfactant-rich phase (Vs) showed higher thermal stability (activation energy (Ea) 23.8 kJ/mol) compared to non-entrapped ones (Ea 76.5 kJ/mol). The antioxidant activity of separated polyphenols remained unaffected as determined by the 1,1-diphenyl-2-picrylhydrazyl method.
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