Total Oxygen Radical Absorbance Capacity Values Research Articles

Antioxidant properties and lipid composition of selected microalgae

Marine and freshwater microalgae were evaluated for their antioxidant properties and lipid composition. Both lipophilic (L) and hydrophilic (H) oxygen radical absorbance capacity (ORAC) values were measured. Among the tested microalgae, the marine microalga Nannochloropsis granulata showed the highest total ORAC value at 6948 μmol TE (100 g)−1, followed by the freshwater species Neochloris oleoabundans at 4508 μmol TE (100 g)−1 and Scenedesmus obliquus at 4406 μmol TE (100 g)−1 of algal biomass. Freeze-dried algal biomass was also examined for lipid content by the Folch method. Lipid content ranged from 30.9 to 49.3% and linear regression analysis revealed a statistically significant correlation between the lipid content and the ORAC values. Tested microalgae showed moderate and dose-dependent DPPH radical scavenging activity. The total phenol assay shows that marine microalga Tetraselmis chui had the highest phenolic content at 57.5 μmol GAE g−1 and N. oleoabundans had the lowest at 26.6 μmol GAE g−1 of MeOH extract. A statistically significant correlation was detected between DPPH radical scavenging activity and the phenolic content. Fatty acid analysis revealed that polyunsaturated fatty acids constituted > 45% of the total fatty acid content in N. oleoabundans, Phaeodactylum tricornutum, Porphyridium aerugineum, S. obliquus, and Scenedesmus sp. Total carotenoid concentration ranged from 1.1 to 29.5 mg g−1 of dry algal biomass. Lutein, zeaxanthin, and β-carotene are common carotenoids found in most of the algae tested. P. tricornutum contains significant amount of fucoxanthin at 24.3 mg g−1 algal biomass. These carotenoids also contributed to the overall antioxidative activity of microalgae.

Effects of cooking and in vitro digestion of rice on phenolic profiles and antioxidant activity

The aim of this study was to analyze the content and distribution of free and bound phenolic components and the oxygen radical absorbance capacity (ORAC) antioxidant activity of brown and polished rice after cooking and in vitro digestion. The results showed that cooking decreased the free and bound phenolic and flavonoid contents and ORAC values. Cooking decreased the total phenolic content of brown and polished rice by 47.9% and 71.0%, total flavonoid content by 72.8% and 82.5%, and total ORAC values by 31.8% and 72.9%, respectively. After in vitro digestion, the total phenolic content, total flavonoid content, and total ORAC values had increased by 195.6%, 34.6% and 185.7%, respectively, in brown rice, and by 403.3%, 13.1% and 293.4% respectively, in polished rice, compared with the cooked samples. Seven individual phenolics (gallic, protocatechuic, chlorogenic, caffeic, syringic, coumaric, and ferulic acids) were detected in both free and bound forms. The results showed that the phytochemical content and its antioxidant activity after cooking will be underestimated if the bound fraction after in vitro digestion is not included in calculations. The results of this study show that cooking affects the phenolic content and antioxidant capacity of rice. However, the in vitro digestion process could actually improve the digestion and absorption of beneficial components of cooked rice at the intestinal level.

In vitro and ex-vivo cellular antioxidant protection and cognitive enhancing effects of an extract of Polygonum minus Huds (Lineminus™) demonstrated in a Barnes Maze animal model for memory and learning

BackgroundPolygonum minus Huds.is a culinary flavouring that is common in South East Asian cuisine and as a remedy for diverse maladies ranging from indigestion to poor eyesight. The leaves of this herb have been reported to be high in antioxidants. Flavonoids which have been associated with memory, cognition and protection against neurodegeneration were found in P. minus.MethodThis study examined a P. minus aqueous extract (Lineminus™) for its antioxidant activity using the Oxygen Radical Absorbance Capacity (ORAC) assay, the ex vivo Cellular Antioxidant Protection of erythrocytes (CAP-e) assays and for potential anticholinesterase activity in vitro. Cognitive function and learning of Lineminus™ was evaluated using scopolamine induced cognition deficits in a Barnes maze, rodent model of cognition.ResultsThe extract displayed in vitro antioxidant activity with a total ORAC value of 16,964 μmole TE/gram. Cellular antioxidant protection from free radical damage using the CAP-e assay, with an IC50 of 0.58 g/L for inhibition of cellular oxidative damage, was observed. The extract inhibited cholinesterase activity with an IC50 of 0.04 mg/ml with a maximum inhibition of 68%. In a rodent model of cognition using scopolamine induced cognition deficits in the Barnes maze, the extract attenuated scopolamine induced disruptions in learning at the higher dose of 100 mg/kg.ConclusionThese data shows that P. minus possesses antioxidant and anticholinesterase activity and demonstrated enhanced cognition in vivo. The data suggest neuroprotective properties of the extract.

Antioxidant Capacity and Polyphenol Content of Extracts from Crops Cultivated in Japan, and the Effect of Cultivation Environment

Oxygen radical absorbance capacity (ORAC) value and polyphenol contents of extracts from 71 crops cultivated in Japan were determined. Hydrophilic ORAC values (H-ORAC) ranged from 194 − 29,830 μmol TE/100 g fresh weight (FW), whereas lipophilic ORAC values (L-ORAC) ranged from 6 − 2,076 μmol TE/100 g FW. High total ORAC value was indicated in the following vegetables and fruits: mulukhiya (Corchorus olitorius), perilla (Perilla frutescens), water spinach (Ipomoea aquatica), edible burdock (Arctium lappa), blueberries (Vaccinium corymbosum) and hardy kiwifruit (Actinidia arguta) (6,562 − 31,802 μmol TE/100 g FW). These extracts showed a strong positive correlation between ORAC value and polyphenol content (r = 0.98). In addition, to gain a better understanding of ORAC variability in Japanese crops, we also discussed the influence of environmental factors on the ORAC value of stem mustard (Brassica juncea) “Umino” grown in three different regions. Regional variations of ORAC in stem mustard likely result from different levels of ultraviolet radiation and fertilizer application regimens specific to those regions.

Antioxidants in digestive tracts and gonads of green urchin ( Strongylocentrotus droebachiensis)

Digestive tracts and gonads of green urchin ( Strongylocentrotus droebachiensis) were evaluated for their antioxidant potential and total phenol and flavonoid contents. Antioxidant potentials of freeze-dried samples were evaluated using lipophilic and hydrophilic oxygen radical absorbance capacity (ORAC) assays. Analyzed samples showed antioxidant activity with total ORAC values of 864 and 885 μmol of TE/g d.w. for digestive tracts and gonads, respectively. Acetonitrile-rich and ethyl acetate extracts from freeze-dried samples showed ORAC values (1500–2100 μmol of TE/g) higher than crude tissues (∼870 μmol of TE/g), while water-rich extracts were less active (260–370 μmol of TE/g). Eluates 1 and 2 obtained from C 18 solid-phase extraction of the water-rich fraction showed ORAC values (650–1600 μmol of TE/g) up to 6 times higher than their parent extracts. Total phenol and flavonoid contents of freeze-dried samples ranged from 53 to 123 mg of GAE/100 g d.w. and 1.4–1.8 mg of RE/100 g, respectively. ORAC values from digestive tracts samples showed significant correlations with total phenols ( r 2 = 0.76, p = 0.049, n = 12) and flavonoids ( r 2 = 0.80, p = 0.021, n = 12), while a very weak correlation was observed for samples from gonads. This is the first study to quantify antioxidant properties of green urchin tissues, and show that edible gonads might provide valuable antioxidants to consumers while digestive tracts might be valorized as an alternative source of antioxidants in food additive ingredients.

Ascorbic acid contribution to ORAC values in berry extracts: An evaluation by the ORAC-pyrogallol red methodology

An oxygen radical absorbance capacity (ORAC) method based on pyrogallol red bleaching (ORAC-PGR) was used to evaluate the scavenging activity of berry extracts (blackberry, blueberry, and raspberry). Among berry extracts, only raspberry protected pyrogallol red through a clear induction time, related exclusively to ascorbic acid. The lag time allowed an estimation of the ascorbic acid concentration and its contribution to the total ORAC value, estimating that 66% of the ORAC-PGR value of raspberry is related to ascorbic acid. Also, from the induction time, an ascorbic acid concentration of 36 mg per 100 g of fresh weight was estimated for raspberry samples. The ORAC-PGR procedure could be considered as a fast and specific methodology for an estimation of ascorbic acid concentrations in complex samples.

Antioxidant Capacity of 55 Medicinal Herbs Traditionally Used to Treat The Urinary System: A Comparison Using A Sequential Three-Solvent Extraction Process

The prevalence of chronic renal disease exceeds 10% in industrialized societies. Oxidative damage is thought to be one of the main mechanisms involved in nearly all chronic renal pathologies. We aimed to use the oxygen radical absorbance capacity (ORAC) method and a sequential multisolvent extraction process to compare the in vitro antioxidant capacity of 55 medicinal herbs and prioritize them for in vivo studies investigating the value of herbal therapies in the treatment of renal disorders. The herbs were chosen on the basis of their traditional use in kidney or urinary system disorders, or because they have attracted the attention of recent investigations into renal pathologies. The three solvents used for extraction were ethyl acetate, methanol, and 50% aqueous methanol. Silybum marianum (milk thistle) seed and Camellia sinensis (tea) leaf, both known to possess high antioxidant capacity, were included for comparison. Twelve of the 55 herbs were comparable to or exceeded ORAC levels of milk thistle seed or tea leaf. The highest radical-scavenging activity was found in Olea europaea (olive leaf), Cimicifuga racemosa (black cohosh), Rheum palmatum (rhubarb), Glycyrrhiza glabra (licorice), and Scutellaria lateriflora (Virginia skullcap). The antioxidant capacity of many of the herbs studied may, at least in part, be responsible for their reputation as being protective of organs of the urinary system. Overall, the combined ORAC values for the methanol and aqueous methanol extracts comprised 84% of the total ORAC value. Sequential extraction with solvents of different polarities may be necessary to fully extract the antioxidant principles from medicinal plants.

Alkylperoxyl radical scavenging activity of red leaf lettuce (Lactuca sativa L.) phenolics.

Although lettuce may provide relatively low levels of antioxidative phytochemicals which may contribute to human health, lettuce leaf extracts in fact contained compounds with high specific peroxyl radical scavenging activities. After determining the extraction conditions that minimized phenolic oxidation and produced the highest oxygen radical absorbance capacity (ORAC) values, the phenolic compounds from red leaf lettuce were separated by reverse-phase high-performance liquid chromatography (HPLC). The primary phenolic compounds in the leaf tissue extracts were mono- and dicaffeoyltartaric acid (CTA and DCTA), mono- and dicaffeoylquinic acid (CQA and DCQA), quercetin 3-malonylglucoside (QMG), quercetin 3-glucoside (QG), cyanidin 3-malonylglucoside (CMG), and an unknown phenolic ester (UPE). Significant levels of DCQA were only found after wounding. Using the new fluorescein-based ORAC assay procedures, fractions from the HPLC analyses were assayed for peroxyl radical absorbance capacity. Using absorbance to estimate concentration, the decreasing order of contribution to the total ORAC value of an extract from wounded tissue was QMG > DCQA > CMG > DCTA > UPE > QG > CTA. The decreasing order of the specific peroxyl radical scavenging activities was CMG > QG > DCTA > DCQA > QMG > UPE > CQA > CTA. Since the concentrations of plant flavonoid and phenolic acid esters are sensitive to environmental factors, this information may be used to develop pre- and postharvest conditions which increase the dietary benefits of leaf lettuce.

A Device for the Semiautomatic Determination of Oxygen-Radical Absorbance Capacity

The oxygen-radical absorbance capacity (ORAC) assay has become a standard method to quantify the antioxidative properties of phytonutrients in fruit and vegetable extracts. However, it is usually not possible to determine directly the contribution of specific phytonutrients to the total ORAC value. Separation of the components in the plant extracts by HPLC followed by ORAC analyses of the column fractions might permit the determination of free radical-scavenging profiles. The accurate determination of ORAC values may require 1 to 2 h/sample. Considering the number of samples that would be generated by a single HPLC separation, a device was constructed which permits up to 45 simultaneous ORAC analyses. Varying degrees of automation were included in the design. Furthermore, since the assay has a Q10 for peroxyl radical-scavenging of about 3, elevation of the assay temperature from the standard 37 to 47°C significantly reduced the assay times. Relatively simple modifications would allow the apparatus to be used in a variety of time-dependent fluorescence and absorbance assays.