Home About us Contact
|
Home About us Contact | ||
|
|
||
Highest Antioxidant Activity (highest + antioxidant_activity)
Selected AbstractsThe variation of antioxidant activities and chemical composition of essential oils of Teucrium orientale L. var. orientale during harvesting stagesFLAVOUR AND FRAGRANCE JOURNAL, Issue 5 2004Ali Yildirim Abstract The aerial parts of Teucrium orientale L. var. orientale were collected at the budding, ,owering and vegetative stages. In the each stage, essential oils were obtained by hydrodistillation and steam distillation. The chemical compositions of the essential oils were analysed by GC and GC,MS; 43 different compounds were determined in total, and more than 96% of the essential oils were identi,ed by GC and GC,MS. They contain mainly linalool, , -caryophyllene, 3-octanol, phytol, , -bourbonene and germacrene D. Among the steam distillation oils, the highest 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity was found at the budding stage and the lowest at the vegetative stage. At all stages, the DPPH radical scavenging activities of hydrodistillation oils were markedly lower than those of steam distillation oils. Steam distillation oils of the budding and ,owering stages showed the highest antioxidant activities. However, steam distillation oils of the vegetative stage in two doses (200 and 400 µg) did not show antioxidant activities (p > 0.05, between these and control). None of the hydrodistillation oils showed detectable antioxidant activity. In contrast, in the presence of 400 µg hydrodistillation oils of ,owering stage, prooxidant activity was found in the linoleic acid emulsion. Copyright © 2004 John Wiley & Sons, Ltd. [source] Chemical composition and antioxidant and radical-scavenging activities of Periploca laevigata root bark extractsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 5 2009Hajji Mohamed Abstract BACKGROUND: The root powder of Periploca laevigata is used for preparing soft drinks and as an aromatic in Tunisia. The infusion or decoction of its root bark has widespread use in folk medicine. The plant is used to treat digestive disorders and hypertensive effects as well as other health problems. RESULTS: The antioxidant activities of extracts of P. laevigata root bark obtained with solvents of different polarity were investigated using assays of 1,1-diphenyl-2-picrylhydrazyl radical-scavenging activity, ferric-reducing capacity, ,-carotene-bleaching ability, hydroxyl radical-scavenging activity and lipid peroxidation inhibition. The methanol extract, with the highest amount of total phenolics and flavonoids, showed the highest antioxidant activities in all assays, followed by the water extract. Gas chromatography/mass spectrometry was used to determine the composition of the water and methanol extracts. Thirty-four compounds were identified in the methanol extract, with proflavine (516.2 g kg,1 dry matter (DM)) and 4-methoxysalicylaldehyde (198.3 g kg,1 DM) being the most abundant. Sixteen compounds were identified in the water extract, of which 4-hydroxy-3-methoxyphenethylene glycol (351.2 g kg,1 DM) was the main component. CONCLUSION: As far as is known, this is the first report on the chemical composition and biological activities of phenolic extracts from P. laevigata. The results of the study indicate that the root bark of this plant might be a good candidate for further investigation in developing new antioxidants. Copyright © 2009 Society of Chemical Industry [source] Effects of tocopherols and tocotrienols on the inhibition of autoxidation of conjugated linoleic acidEUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 4 2010Soon-Nam Ko Abstract The effect of eight vitamin E homologues, i.e. ,-, ,-, ,-, and ,-tocopherol and ,-, ,-, ,, and ,-tocotrienol, on the inhibition of autoxidation of conjugated linoleic acid (CLA) were investigated. The oxidation was carried out in the dark for 21 days at 50,°C and monitored by peroxide values (PV) and TBA values. The levels of the individual vitamin E homologues in CLA during storage were determined by HPLC. ,-Tocopherol exhibited the highest antioxidant activity among the homologues tested in this study when the antioxidant activities of the individual homologues in CLA were compared by PV. The order of antioxidant activity of eight homologues was ,-tocopherol,>,,-tocopherol,=,,-tocotrienol , ,-tocotrienol,>,,-tocopherol,=,,-tocotrienol,>,,-tocopherol,=,,-tocotrienol. The degradation rates of , -tocopherol and , -tocotrienol were faster than those of the other homologues, whereas ,-tocopherol had the highest stability in CLA during storage. All homologues exhibited an antioxidant activity by inhibiting the formation of secondary oxidation products. It appears that ,-tocotrienol and ,-tocotrienol have significantly higher antioxidant activities for secondary oxidation in CLA than ,-tocopherol and ,-tocopherol. Meanwhile, the other homologues, namely ,-tocopherol, ,-tocotrienol, ,-tocopherol, and ,-tocotrienol, exhibited similar antioxidant activity for secondary oxidation in CLA. [source] Antioxidant properties of methanolic extracts from different parts of Sclerocarya birreaINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 5 2008Abdalbasit A. Mariod Summary The methanolic extracts from Sclerocarya birrea leaves (SCL), roots (SCR), barks (SCB), and kernel oil cake (SCK) were examined for radical scavenging capacities and antioxidant activities. The total phenolics of the extracts was determined spectrophotometrically according to the Folin-Ciocalteau method using gallic acid as standard solution. The total phenolic compounds were found as 304.5, 367.5, 593, 148.0 and 258.0 mg g -1 of dry product, respectively. The extracts of SCL, SCR, SCB and SCK were markedly effective in inhibiting the oxidation of linoleic acid and subsequent bleaching of ,-carotene in comparison with the control. Based on oxidation of ,-carotene/linoleic acid, the SCK extract is the most effective followed by SCR, SCL and SCB extract. The antioxidant activity determined by the DPPH (1,1-diphenyl-,-picrylhydrazyl) method revealed that the SCK extract had the highest antioxidant activity on DPPH free radicals followed by SCB, SCR and SCL extracts. The effect of different extracts on the oxidative stability of sunflower oil at 70 °C was tested in the dark and compared with BHA. The oil peroxide values (PVs) were generally lower with the addition of extract in comparison to a control. [source] ANTIOXIDANT ACTIVITY AND PHENOLIC ACID CONSTITUENTS OF CHESTNUT (CASTANIA SATIVA MILL.) HONEY AND PROPOLISJOURNAL OF FOOD BIOCHEMISTRY, Issue 4 2009ALI OSMAN SARIKAYA ABSTRACT This study describes the constituents of phenolic acids and antioxidant activities of chestnut (Castania sativa Mill.) honeys and propolis in Turkey. Antioxidant activity of the chestnut honeys and propolis were examined by three different methods, namely scavenging of free radical 2, 2-diphenyl-1-picrylhydrazyl, FRAP, and cupric reducing antioxidant power. Total phenolic contents were determined by using Folin,Ciocalteu reagent as GA equivalent. The phenolic constituents were also determined by HPLC. The antioxidant activities were compared with standard antioxidants such as catechin, BHT and Trolox. The antioxidant activities of all the samples were found high and related to the sample concentrations. The ethanolic propolis extracts showed the highest antioxidant activity. The major phenolic acids of the chestnut honeys and propolis identified by HPLC with PDA detection were coumaric acid, FA, cinnamic acid, CA and ChA. PRACTICAL APPLICATIONS In this study, some phenolic acid components and antioxidant capacity of chestnut (Castania sativa Mill.) honey and propolis were measured. The comparative findings from antioxidant activities and phenolic acid analyses of honey and propolis samples of chestnut origin provide important criteria for considering their nutritional and nutraceutical potentials. Comparison of our results with literature data also ranks the chestnut honey and propolis as better sources of antioxidants among those from other floral origins. [source] Storage affects the phenolic profiles and antioxidant activities of cherries (Prunus avium L) on human low-density lipoproteinsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 9 2004Berta Gonçalves Abstract Four sweet cherry cultivars (cvs), Burlat, Saco, Summit and Van, were analysed at harvest and after storage at 2 and 15 °C for 30 and 6 days respectively. Phenolic profiles in methanolic extracts of freeze-dried samples of the fresh and differently stored cherries were quantified by high-performance liquid chromatography. Hydroxycinnamates dominated in all samples and represented 60,74% by weight of the phenols in the fresh and stored samples of the cvs Saco, Summit and Van, and 45% by weight of the phenols in the cv Burlat samples, which were richer in anthocyanins. The relative and total levels of hydroxycinnamates, anthocyanins, flavonols and flavan-3-ols varied among cultivars and during storage. Storage at 15 °C increased the phenol levels, particularly the cyanidin-3-rutinoside concentration. Cold storage induced decreased total phenol levels in the cvs Summit and Van but increased total phenol levels in the cvs Burlat and Saco. Phenolic cherry extracts inhibited low-density lipoprotein oxidation in vitro in a dose-dependent manner. Extracts of freshly harvested cherries exhibited significantly higher antioxidant activities than extracts of stored samples. The cv Summit samples had the highest antioxidant activity. Differences in the antioxidant effects of the cherry samples were positively correlated with their levels of p -coumaroylquinic acid (p < 0.1) but negatively correlated with their cyanidin-3-rutinoside levels (p < 0.05). Copyright © 2004 Society of Chemical Industry [source] Antioxidant diterpenoids from the roots of Salvia barrelieriPHYTOCHEMICAL ANALYSIS, Issue 4 2009Ufuk Kolak Abstract Introduction The phytochemical and biological studies carried out on Salvia species showed that their extracts and constituents have various biological activities. Objective The aim of this study was the isolation of diterpenoids from the roots of Salvia barrelieri Ettling and the determination of the antioxidant activity. Methodology Chromatographic methods were used for fractionation and isolation, respectively. Structure elucidation was established by spectroscopic methods. Five antioxidant assays were performed. Results Three new abietane diterpenoids barreliol, royleanone 12-methyl ether and 7-epi-salviviridinol, and six known diterpenoids, with a known dammarane triterpenoid, pyxinol were isolated. The absolute stereochemistry of pyxinol was confirmed by X-ray analysis. Conclusion Taxodione exhibited the highest antioxidant activity among the tested compounds. Copyright © 2009 John Wiley & Sons, Ltd. [source] Antioxidant properties of extracts from Alchornea laxiflora (Benth) Pax and HoffmanPHYTOTHERAPY RESEARCH, Issue 7 2003E. Olatunde Farombi Abstract The antioxidant activities of the leaf and root extracts of Alchornea laxiflora, a plant used locally for the preservation of food items in Nigeria, were evaluated using the ferric thiocyanate method, horseradish peroxidase catalysed oxidation of 2,2 azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), , -carotene linoleate model system and Fe2+/ascorbate/H2O2 -induced rat liver microsomal lipid peroxidation. The crude hexane root (HR), methanol root (MR), methanol leaf (ML) and hexane leaf (HL) extracts from A. laxiflora were tested for antioxidant activities. Antioxidant activity decreased in the following order: HR (76.4%), MR (63%), ML (40%) and HL (38%) at a concentration of 0.05% v/v. The antioxidant activity of HR compared to that of butylated hydroxyanisole (BHA) (80%), a standard antioxidant. The total antioxidant activity (TAA) of the crude extracts suggests that activity is highest in the HR compared with the others. The TAA value was estimated to be 8.0 measured as mm of vitamin C equivalent. Six column chromatographic fractions (FI,FVI) from HR showed antioxidant activity to varying extents in the , -carotene model system in the order of FII > FI > FVI > FIII > FIV > FV. FII exhibited the highest antioxidant activity in all model systems utilized, it recorded a higher antioxidant activity than BHA and quercetin in the , -carotene linoleate and Fe2+/ascorbate/H2O2. TLC analysis of fraction II revealed the presence of terpenoid compounds (radiant green coloration with 2,4 dinitrophenylhydrazine). Our results suggest that A. laxiflora contains potent natural antioxidants and may therefore be relevant in the preservation of lipid food products, which are prone to oxidation and rancidity. Copyright © 2003 John Wiley & Sons, Ltd. [source] EFFECT OF DIRECT APPLICATIONS OF SAGE (SALVIA OFFICINALIS L.) LEAVES ON OXIDATIVE STABILITY OF SUNFLOWER OIL DURING ACCELERATED STORAGEJOURNAL OF FOOD QUALITY, Issue 5 2009EDA ÇALIKO ABSTRACT In this study, various sage applications were examined on oxidative stability of sunflower oil during accelerated storage. There are three applications: (1) direct sage leaves (S); (2) deodorized sage leaves (DeS); and (3) essential oil of sage leaves. The main compounds of essential oil were identified as, -thujone (35.87%),, -thujone (14.41%), 1,8-cineol (10.59%) and camphor (10.09%). Oxidative stability of these three applications was tested by Schall Oven test at 60C applying peroxide value and conjugated dienes, and Rancimat at 110C. Whereas the highest antioxidants activity was found for 2% S followed by 0.5% S and 2% DeS, all sage treatments statistically retarded the oxidation compared with the control sample. The most appealing result was that the residue can be used as a natural antioxidants. That means the reuse of residue may decrease economic losses and health risk in comparison with synthetic antioxidants and extracts because it is completely natural and contains no residual solvent. PRACTICAL APPLICATIONS While almost all of previous studies were concentrated on the use of herb extracts, our study investigates the results of direct application of sage on oxidation. Especially with this study, we have evaluated a possible application area for sage residue leftover after the deodorization process. [source] | ||||||||||