Investigation of antioxidant activities of stored at different temperatures.

In this study, the antioxidant capacity of oyster mushroom () stored in five different temperature environments was investigated by DPPH (1,1 diphenyl-2-picryl hydrazyl) radical scavenging method. The antioxidant capacity results of oyster mushroom extracts were examined by spectroscopic measurements and expressed as percent of inhibition. The IC values of mushroom samples were calculated with DPPH method using calibration equations, and change in antioxidant properties was also tried to decipher by SEM images.

Antioxidant/prooxidant effects of α-tocopherol, quercetin and isorhamnetin on linoleic acid peroxidation induced by Cu(II) and H2O2.

The peroxidation of linoleic acid (LA) in the presence of copper(II) (Cu(II)) ions alone and with α-tocopherol (α-TocH) was investigated in aerated and incubated emulsions at 37 °C and pH 7. Additionally, the effects of quercetin (QR) and its O-methylated derivative, isorhamnetin (IR), as potential antioxidant protectors were studied in the (Cu(II) + TocH)-induced LA peroxidation system. Cu(II)-induced LA peroxidation followed pseudo-first-order kinetics with respect to primary (hydroperoxides) and secondary (aldehydes- and ketones-like) oxidation products, which were determined by ferric thiocyanate and thiobarbituric acid-reactive substances methods, respectively.

Polar paradox revisited: analogous pairs of hydrophilic and lipophilic antioxidants in linoleic acid emulsion containing Cu(II).

Background: Literature data are scarce on the activities of analogous pairs of hydrophilic and lipophilic antioxidants related to the 'polar paradox' distinguishing antioxidants based on their partitioning between lipids and water. The peroxidation of linoleic acid (LA) in the presence of either Cu(II) ions alone or Cu(II) ions combined with Trolox (TR), ascorbic acid (AA), hydroquinone (HQ) and gallic acid (GA), as hydrophilic antioxidants, or with α-tocopherol (TocH), ascorbyl palmitate (AP), tert-butyl hydroquinone (TBHQ) and propyl gallate (PG), as their respective lipophilic analogues, was investigated in aerated and incubated emulsions at 37 °C and pH 7.

Results: LA peroxidation induced by Cu(II) followed pseudo-first-order kinetics with respect to the formation of primary (hydroperoxides) and secondary (aldehyde- and ketone-like) oxidation products, which were determined by ferric thiocyanate (Fe(III)-SCN) and thiobarbituric acid-reactive substances (TBARS) methods respectively.

Antioxidant protective effect of flavonoids on linoleic acid peroxidation induced by copper(II)/ascorbic acid system.

Antioxidants are compounds that can delay or inhibit lipid oxidation. The peroxidation of linoleic acid (LA) in the absence and presence of Cu(II) ion-ascorbate combinations was investigated in aerated and incubated emulsions at 37°C and pH 7. LA peroxidation induced by copper(II)-ascorbic acid system followed first order kinetics with respect to hydroperoxides concentration.