Solvent effect on the Thermodynamics of the Oxidation of Potential Antioxidant Garlic Compounds (original) (raw)
Related papers
Journal of Physical Organic Chemistry, 2008
Thermodynamics of competing oxidation reactions of allyl methyl disulfide by hydrogen peroxide: a first principle molecular computational study on the conformations of allyl methyl disulfide and its oxidized products y Allyl methyl disulfide, a peroxide scavenger, was studied together with three isomeric (two sulfoxides and one epoxide) forms of its mono-oxidized products. After a full conformational study of the reactant and three isomeric oxidized forms, the geometries were optimized at B3LYP/6-31G (d) level of theory. The epoxide form turned and to be more stable than either one of the two isomeric sulfoxides. Changes for Thermodynamic functions of oxidation reactions were calculated and from the DG reaction values the equilibrium constant for the interconversions of the oxidized products were estimated. Bader-type AIM analyses were performed on the electron density, computed at the B3LYP/6-311þþG (d,p) level of theory. In several of the sulfoxide conformations C-HÁÁÁO --S< secondary interactions were observed.
Garlic Oil Polysulfides: H2S- and O2-Independent Pro-Oxidants in Buffer and Anti-Oxidants in Cells
American journal of physiology. Regulatory, integrative and comparative physiology, 2016
The health benefits of garlic and other organosulfur-containing foods are well recognized and have been attributed to both pro-oxidant and antioxidant activities. The effects of garlic are surprisingly similar to those of hydrogen sulfide (H2S) which is also known to be released from garlic under certain conditions. However, recent evidence suggests that polysulfides, not H2S, may be the actual mediator of physiological signaling. In this study we monitored formation of H2S and polysulfides from garlic oil in buffer and in HEK293 cells with fluorescent dyes, AzMC and SSP4, respectively and redox activity with two redox indicators roGFP and DCF. Our results show that H2S release from garlic oil in buffer requires other low molecular weight thiols such as cysteine (Cys) or glutathione (GSH), whereas polysulfides are readily detected in garlic oil alone. Administration of garlic oil to cells rapidly increases intracellular polysulfide but has minimal effects on H2S unless Cys or GSH ar...
Peroxyl-Radical-Scavenging Activity of Garlic: 2-Propenesulfenic Acid versus Allicin
The Journal of Physical Chemistry B, 2009
The OOH radical reactions with allicin and its Cope elimination products (2-propenesulfenic acid and thioacrolein) in aqueous solution have been studied. The CBS-QB3 quantum chemistry method has been used, with geometries and frequencies at BHandHLYP/6-311++G(d,p) level and conventional transition state theory. 2-Propenesulfenic acid is predicted to be over 1000 times more reactive toward OOH radical than allicin (2.60 × 10 7 vs 7.38 × 10 3 L mol-1 s-1 , at 298 K). Accordingly, our results strongly support the novel suggestion by Vaidya et al. (Angew. Chem., Int. Ed. 2009, 48, 157) that the active ingredient responsible for the free radical scavenging activity of garlic is actually 2-propenesulfenic acid and not allicin. In addition, direct reaction branching ratios and product distribution for the three studied reactions are proposed for the first time.
Cooked garlic and antioxidant activity: Correlation with organosulfur compound composition
2017
The antioxidant properties and the main beneficial organosulphur compounds of home-cooked garlic samples were studied in order to establish relationships between them. Antioxidant activity was tested by free radical scavenging against 2,2-diphenyl-1-picrylhydrazyl radical (DPPH Å) and 2,2 0-azino-bis-(3-ethylbenzo-thiazoline-6-sulfonic acid) diammonium salt (ABTS +Å), Fe(III) reducing ability (FRAP) and linoleic acid co-oxidation initiated by soybean lipoxygenase in a micelle system. DPPH, ABTS and FRAP assays showed the highest activity for raw garlic samples, while b-carotene bleaching assay yielded the highest activity for stir-fried garlic. Pure organosulphur compounds tested by DPPH, FRAP and b-carotene bleaching assays showed that allicin had an antiradical action mechanism, as well as iron reducing capacity; while antioxidant activity was the main mechanism for ajoenes and 2-VD. To our knowledge, this study is the first demonstration that home-cooked garlic retains its antioxidant activity, and, at the same time, elucidates the mechanisms involved in this activity.
Biological properties of garlic and garlic-derived organosulfur compounds
Environmental and Molecular Mutagenesis, 2009
Medicinal properties of garlic (Allium sativum) have been widely known and used since ancient times till the present. Garlic enhances immune functions and has antibacterial, antifungal and antivirus activities. It is known to prevent platelet aggregation, and to have hypotensive and cholesterol-and triglyceride-lowering properties, although the latter features have been questioned. This review is focused on anticancer efficacy of Allium sativum, and attempts to explain the mechanisms of this action. Medicinal properties of garlic rely upon organosulfur compounds mostly derived from alliin. Organosulfur compounds originating from garlic inhibit carcinogen activation, boost phase 2 detoxifying processes, cause cell cycle arrest mostly in G2/M phase, stimulate the mitochondrial apoptotic pathway, increase acetylation of histones. Garlic-derived sulfur compounds influence also gap-junctional intercellular communication and participate in the development of multidrug resistance. This review presents also other little known aspects of molecular action of garlicderived compounds, like modulation of cellular redox state, involvement in signal transduction and post-translational modification of proteins by sulfane sulfur or by formation of mixed disulfides (S-thiolation reactions). Environ. Mol. Mutagen. 50:247-265, 2009. V V C 2009 Wiley-Liss, Inc.
The Journal of nutrition, 2008
Much evidence in the last few years suggests that the antiproliferative effects of various garlic secondary metabolites in in vitro experimental systems are due to redox-based mechanisms. In particular, sulfur-containing allyl compounds have been demonstrated to generate reactive oxygen species and to modify directly the redox state of specific reactive cysteines on protein surfaces. On the basis of such properties, allyl compounds, in particular the ones present in the oil-soluble fraction of garlic extracts, can function as modulators of several redox-mediated signaling pathways related to the activation of mitogen-activated protein kinases, cell cycle, DNA repair, and cell demise. However, even though many in vitro studies have tried to dissect the mechanisms of action of garlic derivatives, research in this field is still incomplete and questions about bioavailability, biotransformation, and pro-oxidant activity are still unanswered. This review discusses recent findings on such...
European Journal of Lipid Science and Technology, 2019
In this research, the effect of adding garlic and synthetic antioxidant to butter produced on both quality characteristics and oxidation stability during the storage (1st, 15th, 30th, 45th, 60th, 75th, and 90th days) process is investigated. With this aim, two replicates of butter samples as control, containing different proportions of garlic (butter treated with 2.5%, 5%, 7.5%, 10% crushed garlic) and with 50 ppm butylated hydroxytoluene (BHT) added are prepared. 2,2′-Azinobis-(3-ethylbenzthiazoline-6-sulfonate) and 2,2-diphenyl-1-picrylhydrazyl free radical-scavenging ability, ferric reducing antioxidant power value of garlic are found as 26.05%; 87.48%; 70 mm mL −1 , respectively. Total phenolic content, total flavonoids, and total antioxidant capacity of fresh garlic are determined. The main components of essential oil of garlic are determined. The rate of oxidation decreases as the garlic rate increases. The highest sensory analysis scores for the first days of storage are for the control and butter with 50 ppm BHT added, followed by samples with 5%, 2.5%, and 7.5% garlic added. At the end of storage, the highest sensory analysis scores are obtained by the butter with 5% garlic added. The butter with 10% garlic added is not liked in terms of sensory properties. Practical Applications: Oxidation-causing or accelerating factors are oxygen, light, temperature, metal ions, some pigments, and degree of unsaturation. Oxidation is eliminated when these factors are eliminated. But in practice this is not possible. Therefore, it is very difficult to prevent oxidation without adding any material. Antioxidants are the most effective substances in the food industry for the production, storage, transport, and marketing of vegetable and animal fats and fat-containing foods, delaying the effect of atmospheric oxygen at normal temperatures, preventing food spoilage, and rancidity for a certain period of time. Due to the carcinogenic effects of synthetic antioxidants, interest in natural antioxidants has increased. It is known that garlic has antioxidant effects. Natural antioxidants are used in the food industry for different purposes due to their extensive bioactivity profile. Peroxide value and thiobarbituric acid tests are generally used to determine the degree of lipid oxidation in butter.
International Journal of Food Properties, 2015
A novel aged garlic extract (AGE), with high antioxidant activities, was prepared by soaking sliced garlic in 10% ethanol solution for 90 days. In order to locate the antioxidant ingredients of AGE, 2,2-azinobis-6-s (3-ethylbenzothiazoline sulfonic acid) (ABTS) assay, hydroxyl free radical assay, 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay and ferric reducing/antioxidant power (FRAP) assay were conducted to guide the fractionation of AGE by means of extraction. As a result, the ethyl acetate fraction was identified as the highest antioxidant activity in AGE. Therefore, the ingredient informations of the ethyl acetate fraction were obtained through GC-MS and UPLC-MS/MS analysis. Some phenols and diallyl disulphide, Downloaded by [Universiti Putra Malaysia] at 01:39 15 June 2015 A c c e p t e d M a n u s c r i p t 2 5-(hydroxymethyl)-2-furancarboxaldehyde, S-allyl-cysteine (SAC), S-allyl-mercaptocysteine (SAMC), 1-methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid were identified as potent antioxidants in AGE by GC-MS and UPLC-MS/MS, respectively. The biological activities and formation mechanisms of these identified compounds were discussed.
Evaluation of hydroxyl radical-scavenging property of garlic
Molecular and Cellular Biochemistry, 1996
Garlic has been reported to provide protection against hypercholesterolemic atherosclerosis and ischemia-reperfusion-induced arrhythmias and infarction. Oxygen free radicals (OFRs) have been implicated as causative factors in these diseases and antioxidants have been shown to be effective against these conditions. The effectiveness of garlic in these disease states could be due to its ability to scavenge OFRs. However, the OFR-scavenging activity of garlic is not known. Also it is not known if its activity is affected by cooking. We therefore investigated, using high pressure liquid chromatography, the ability of garlic extract (heated or unheated) to scavenge exogenously generated hydroxyl radical (·OH). ·OH was generated by photolysis of H202 (1.2–10 pmoles/ml) with ultraviolet (UV) light and was trapped with salicylic acid (500 nmoles/ml). H2O2 produced ·OH in a concentration-dependent manner as estimated by ·OH adduct products 2,3-dihydroxybenzoic acid (DHBA) and 2,5-DHBA. Garlic extract (5–100 μl/ml) produced an inhibition (30–100%) of 2,3-DHBA and 2,5-DHBA generated by photolysis of H202 (5.00 pmoles/ml) in a concentration-dependent manner. Its activity is reduced by 10% approximately when heated to 100°C for 20, 40 or 60 min. The extent of reduction in activity was similar for the three heating periods. Garlic extract prevented the ·OH-induced formation of malondialdehyde in the rabbit liver homogenate in a concentration-dependent manner. It alone did not affect the MDA levels in the absence of ·OH. These results indicate that garlic extract is a powerful scavenger of ·OH and that heating reduces its activity slightly.