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Lipid Peroxidation
Antioxidant and radical scavenging properties of curcumin.
Ak T, Gülçin I. Epub 2008 May 7. Chem Biol Interact. 2008 Jul 10;174(1):27-37.
Faculty of Arts and Sciences, Department of Chemistry, Atatürk University, TR-25240 Erzurum, Turkey.
Curcumin (diferuoyl methane) is a phenolic compound and a major component of Curcuma longa L. In the present paper, we determined the antioxidant activity of curcumin by employing various in vitro antioxidant assays such as 1,1-diphenyl-2-picryl-hydrazyl free radical (DPPH*) scavenging, 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging activity, N,N-dimethyl-p-phenylenediamine dihydrochloride (DMPD) radical scavenging activity, total antioxidant activity determination by ferric thiocyanate, total reducing ability determination by the Fe(3+)-Fe(2+) transformation method, superoxide anion radical scavenging by the riboflavin/methionine/illuminate system, hydrogen peroxide scavenging and ferrous ions (Fe(2+)) chelating activities.
Curcumin inhibited 97.3% lipid peroxidation of linoleic acid emulsion at 15 microg/mL concentration (20 mM). On the other hand, butylated hydroxyanisole (BHA, 123 mM), butylated hydroxytoluene (BHT, 102 mM), alpha-tocopherol (51 mM) and trolox (90 mM) as standard antioxidants indicated inhibition of 95.4, 99.7, 84.6 and 95.6% on peroxidation of linoleic acid emulsion at 45 microg/mL concentration, respectively. In addition, curcumin had an effective DPPH* scavenging, ABTS*(+) scavenging, DMPD*(+) scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, ferric ions (Fe(3+)) reducing power and ferrous ions (Fe(2+)) chelating activities. Also, BHA, BHT, alpha-tocopherol and trolox, were used as the reference antioxidant and radical scavenger compounds. According to the present study, curcumin can be used in the pharmacological and food industry because of these properties.
Antioxidant activity of caffeic acid.
Gülçin I. Epub 2005 Oct 21. Toxicology. 2006 Jan 16;217(2-3):213-20.
Faculty of Arts and Sciences, Department of Chemistry, Atatürk University, TR-25240 Erzurum, Turkey. igulcin@atauni.edu.tr
Caffeic acid (3,4-dihydroxycinnamic acid) is among the major hydroxycinnamic acids present in wine; sinapic acid, which is a potent antioxidant. It has also been identified as one of the active antioxidant.
In the present study, the antioxidant properties of the caffeic acid were evaluated by using different in vitro antioxidant assays such as 2-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging, 1,1-diphenyl-2-picryl-hydrazyl free radical (DPPH) scavenging, total antioxidant activity by ferric thiocyanate method, total reductive capability using the potassium ferricyanide reduction method, superoxide anion radical scavenging and metal chelating activities.
Alpha-Tocopherol, trolox, a water-soluble analogue of tocopherol, butylated hydroxyanisole (BHA), and butylated hydroxytoluene (BHT) were used as the reference antioxidant compounds. At the concentrations of 10 and 30 microg/mL, caffeic acid showed 68.2 and 75.8% inhibition on lipid peroxidation of linoleic acid emulsion, respectively.
On the other hand, 20 microg/mL of standard antioxidant such as BHA, BHT, alpha-tocopherol and trolox indicated an inhibition of 74.4, 71.2, 54.7 and 20.1% on peroxidation of linoleic acid emulsion, respectively. In addition, caffeic acid is an effective ABTS(+) scavenging, DPPH scavenging, superoxide anion radical scavenging, total reducing power and metal chelating on ferrous ions activities.
In vitro antioxidant activity of silymarin.
Koksal E, Gulcin I, Beyza S, Sarikaya O, Bursal E.
Faculty of Arts and Sciences, Department of Chemistry, Ataturk University, Erzurum, TURKEY. J Enzyme Inhib Med Chem. 2008 Oct 1:1
Silymarin, a known standardized extract obtained from seeds of Silybum marianum is widely used in treatment of several diseases of varying origin. In the present paper, we clarified the antioxidant activity of silymarin by employing various in vitro antioxidant assay such as 1,1-diphenyl-2-picryl-hydrazyl free radical (DPPH.) scavenging, 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging activity, total antioxidant activity determination by ferric thiocyanate, total reducing ability determination by Fe(3+) - Fe(2+) transformation method and Cuprac assay, superoxide anion radical scavenging by riboflavin/methionine/illuminate system, hydrogen peroxide scavenging and ferrous ions (Fe(2+)) chelating activities.
Silymarin inhibited 82.7% lipid peroxidation of linoleic acid emulsion at 30 mug/mL concentration; butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), alpha-tocopherol and trolox indicated inhibition of 83.3, 82.1, 68.1 and 81.3% on peroxidation of linoleic acid emulsion at the same concentration, respectively. In addition, silymarin had an effective DPPH. scavenging, ABTS( radical+) scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, ferric ions (Fe(3+)) reducing power by Fe(3+) - Fe(2+) transformation, cupric ions (Cu(2+)) reducing ability by Cuprac method, and ferrous ions (Fe(2+)) chelating activities.
Also, BHA, BHT, alpha-tocopherol and trolox, were used as the reference antioxidant and radical scavenger compounds. Moreover, this study, which clarifies antioxidant mechanism of silymarin, brings new information on the antioxidant properties of silymarin. According to the present study, silymarin had effective in vitro antioxidant and radical scavenging activity. It could be used in the pharmacological and food industry because of its antioxidant properties.
Antioxidant properties of Indian medicinal plants.
Jadhav HR, Bhutani KK. Phytother Res. 2002 Dec;16(8):771-3.
Department of Natural Products, National Institute of Pharmaceutical Education and Research (NIPER), Sector 67, S. A. S. Nagar - 160 062 Punjab, India.
The antioxidant properties of methanol extracts of 12 Indian medicinal plants, traditionally used in disease areas that probably involve free radical mechanisms, were evaluated by two methods, namely the DPPH (1,1-diphenyl-2-picryl hydrazyl) test and the lipid peroxidation assay. In the latter assay, seven of these extracts showed 90% or more activity compared with the standard, vitamin E and hence were studied in detail after the removal of interfering pigments. The selective pigment removal from the extracts led to an increase in free radical scavenging activity and a decrease in inhibition of lipid peroxidation. Copyright 2002 John Wiley & Sons, Ltd.
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