Determination of in vitro antioxidant and radical scavenging activities of propofol

Propofol (2,6-diisopropylphenol) is a hypnotic intravenous agent with in vivo antioxidant properties. This study was undertaken to examine the in vitro antioxidant activity of propofol using different antioxidant tests including by 1,1-diphenyl-2-picryl-hydrazil (DPPH.) radical scavenging, metal chelating, hydrogen peroxide scavenging, superoxide anion radical scavenging, reducing power and total antioxidant activities. At the concentrations of 25, 50, and 75 microg/ml, propofol exhibited 97.7, 98.6 and 100% inhibition on peroxidation of linoleic acid emulsion, respectively. On the other hand, at the 75 microg/ml concentration of standard antioxidants such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and alpha-tocopherol exhibited 88.7, 94.5, and 70.4% inhibition on peroxidation of linoleic acid emulsion, respectively. In addition, at same concentrations, propofol was shown that it had effective reducing power, DPPH. free radical scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging and metal chelating activities. These various antioxidant activities were compared to standard antioxidants such as BHA, BHT and alpha-tocopherol. These results indicate that propofol prevents lipid peroxidation and radicalic chain reactions. At the same time, propofol revealed more effective antioxidant capacity than BHA, BHT and alpha-tocopherol.     

A Study on the In Vitro Antioxidant Activity of Juniper (Juniperus communis L.) Fruit Extracts

Abstract

This study aimed at evaluating the in vitro antioxidant activity of water and ethanol extracts of juniper (Juniperus communis L., Family Cupressaceae) fruit. The antioxidant properties of both Juniper extracts were studied using different antioxidant assays, including reducing power, free radical scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, and metal chelating activities. Both the water and the ethanol extracts exhibited strong total antioxidant activity. The concentrations of 20, 40, and 60 µg/mL of water and ethanol extracts of juniper fruit showed 75%, 88%, 93%, 73%, 84%, and 92% inhibition on peroxidation of linoleic acid emulsion, respectively. On the other hand, 60 µg/mL of standard antioxidant such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), and α‐tocopherol exhibited 96, 96, and 61 inhibitions on peroxidation of linoleic acid emulsion, respectively. However, both extracts of juniper had effective reducing power, free radical scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, and metal chelating activities at these same concentrations (20, 40, and 60 µg/mL). Those various antioxidant activities were compared to BHA, BHT, and α‐tocopherol as standard antioxidants. In addition, total phenolic compounds in both aqueous and ethanolic juniper extracts were determined as gallic acid equivalents. Accordingly, these results indicate that juniper has in vitro antioxidant properties and these may be major reasons for the inhibition of lipid peroxidation properties.     

Radical scavenging activity and antioxidant capacity of bay leaf extracts

Bay leaves (BL) (Laurus nobilis L., Family: Lauraceae) are traditionally used orally to treat the symptoms of gastrointestinal problems, such as epigastric bloating, impaired digestion, eructation, and flatulence. In this study, lyophilized extracts (both water and ethanol) of BL were studied for their antioxidant properties. The antioxidant activity, reducing power, free radical scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging and metal chelating activities were evaluated to determine the total antioxidant capacity of both BL extracts. Both extracts exhibited strong total antioxidant activity in linoleic acid emulsion. Concentrations of 20, 40, and 60 μg ml^?1 showed 84.9, 95.7, 96.8, and 94.2, 97.7, and 98.6% inhibition of lipid peroxidation of linoleic acid emulsion, for water and ethanol extracts, respectively. On the other hand, 60 μg ml^?1 of the standard antioxidants butylated hydroxyianisole (BHA), butylated hydroxytoluene (BHT), and α-tocopherol exhibited 96.6, 99.1, and 76.9% inhibition of lipid peroxidation in linoleic acid emulsion, respectively. In addition, the both BL extracts had effective reducing power, DPPH? free radical scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging and metal chelating activities at 20, 40, and 60 μg ml^?1. The total amount of phenolic compounds in each BL extract was determined as gallic acid equivalents.     

Antioxidant activity of clove oil – A powerful antioxidant source

The number of methods to measure the antioxidants in botanicals, foods, nutraceuticals and other dietary supplements has increased considerably in the last decade. Clove oil is obtained by distillation of the flowers, stems and leaves of the clove tree. In the present paper, clove oil was evaluated by employing various in vitro antioxidant assay such as α,α-diphenyl-β-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 Fe³⁺–Fe²⁺ transformation method, superoxide anion radical scavenging by riboflavin/methionine/illuminate system, hydrogen peroxide scavenging and ferrous ions (Fe²⁺) chelating activities. Clove oil inhibited 97.3% lipid peroxidation of linoleic acid emulsion at 15 μg/mL concentration. However, under the same conditions, the standard antioxidant compounds such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), α-tocopherol and trolox demonstrated inhibition of 95.4, 99.7, 84.6 and 95.6% on peroxidation of linoleic acid emulsion at 45 μg/mL concentration, respectively. In addition, clove oil had an effective DPPH scavenging, ABTS⁺ scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, ferric ions (Fe³⁺) reducing power and ferrous ions (Fe²⁺) chelating activities. Also, these various antioxidant activities were compared to BHA, BHT, α-tocopherol and trolox as reference antioxidant compounds.     

Radical scavenging and antioxidant activity of tannic acid

Tannic acid, a naturally occurring plant polyphenol, is composed of a central glucose molecule derivatized at its hydroxyl groups with one or more galloyl residues. In the present paper, we examines the in vitro radical scavenging and antioxidant capacity of tannic acid by using different in vitro analytical methodologies 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 using by Fe³⁺–Fe²⁺ transformation method, superoxide anion radical scavenging by riboflavin–methionine-illuminate system, hydrogen peroxide scavenging and ferrous ions (Fe²⁺) chelating activities. Also, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), α-tocopherol and trolox, a water-soluble analogue of tocopherol, were used as the reference antioxidant radical scavenger compounds.Tannic acid inhibited 97.7% lipid peroxidation of linoleic acid emulsion at 15 μg/mL concentration. On the other hand, the above mentioned standard antioxidants indicated an inhibition of 92.2%, 99.6%, 84.6% and 95.6% on peroxidation of linoleic acid emulsion at 45 μg/mL concentration, respectively. In addition, tannic acid had an effective DPPH scavenging, ABTS⁺ radical scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, Fe³⁺ reducing power and metal chelating on ferrous ions activities. Also, those various antioxidant activities were compared to BHA, BHT, α-tocopherol and trolox as references antioxidant compounds. The present study shows that tannic acid is the effective natural antioxidant component that can be used as food preservative agents or nutraceuticals.     

Radical scavenging and in vitro antifungal activities of Cu(II) and Co(II) complexes of the t-butylphenyl derivative of porphyrazine

Co(II) and Cu(II) complexes and metal-free t-butylphenyl peripherally substituted porphyrazine (Pz) have been screened for in vitro antifungal (Aspergillus niger) and antioxidant (free radical scavenging, superoxide radical scavenging, and reducing power) activities. The results were compared with synthetic antioxidants, e.g., butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), trolox, or α-tocopherol. The free radical scavenging activity of H₂Pz was higher than the CuPz complex. However, CuPz complex showed higher superoxide radical scavenging activity than BHA, BHT, and trolox while H₂Pz and CoPz showed weaker activity than BHA, BHT, and trolox. The reducing power of all complexes was similar to that of BHT and α-tocopherol on a per molar basis. The ligand and complexes have antifungal activity against A. niger. The compounds have significant superoxide radical scavenging activity against various antioxidant systems in vitro.     

Screening of antioxidant, antimicrobial activities and chemical contents of edible mushrooms wildly grown in the black sea region of Turkey

The antioxidative activity of the methanol extracts obtained from twelve commonly consumed wild edible mushrooms was investigated according to the phosphomolybdenum method, inhibition of linoleic acid peroxidation, reducing power, metal chelating, O(2)(˙-), DPPH(˙), peroxide and H(2)O(2) scavenging activity in the Black Sea Region of Turky, and compared to standard antioxidant compounds such as a-tocopherol, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), and trolox. Total phenolic compounds, flavonoids, anthocyanins, ascorbic acid, β-carotene and lycopene in the extracts were measured. The antimicrobial activities of extracts were also evalated against gram (-) and (+) bacteria and yeast with disc diffusion method. Hydnum repandum, Lactarius delicious, Lactarius camphoratus, Lactarius piperatus, Ramaria flava, and Agaricus bisporus were greater than α-tocopherol and BHT on antioxidant activity. The lipid peroxidation of L. camphoratus and Lactarius volemus was excellent, and was 58.05% and 61.44% respectively. The DPPH(˙) scavenging effects decreased in the order of R. flava>BHT> Macrolepiota procera>L. camphoratus>L. piperatus>Lactarius volemus>a-tocopherol and were, at 500 μg/ml and were 80.38, 76.61, 69.74, 61.55, 61.47, 61.09, 60.65%, respectively. All the extracts of mushroom also had the stronger chelating effect according to standards. The O(2)(˙-) scavenging effect of extracts of the mushroom species was in order of R. flava>Boletus edulis>Leatiporus sulphureus>M. procera>standards. L. piperatus, L. camphorates, L. volemus, A. bisporus, Chanterellus cibarius, L. sulphureus, H. repandum showed strong antimicrobial activity, especially on E. coli. H. repandum exhibited to be more effective on P. aeruginosa than other bacterial strains.     

Evaluation of antioxidant activity of isoferulic acid in vitro

Isoferulic acid (3-hydroxy-4-methoxycinnamic acid, IFA), the isomer of ferulic acid (4-hydroxy-3-methoxycinnamic acid), is a rare phenolic acid occurring in Rhizoma Cimicifugae. Unlike ferulic acid, which has been well investigated, the antioxidant activity of IFA has not been measured. In this study, IFA was systematically evaluated for its in vitro antioxidant activity for the first time. IC50 values were calculated of 7.30 +/- 0.57, 4.58 +/- 0.17, 1.08 +/- 0.01, 8.84 +/- 0.43, 7.69 +/- 0.39, 1.57 +/- 0.2, 13.33 +/- 0.49 microg/mL, respectively, for lipid peroxidation, DPPH (1,1-diphenyl-2-picrylhydrazyl radical) and ABTS (3-ethylbenzthiazoline-6-sulfonic acid diammonium salt) radical scavenging, reducing power on Fe3+ and CU2+ ions, and hydroxyl and superoxide anion radical scavenging. Comparison with the IC50 values with those of the positive controls, Trolox and butylated hydroxyanisole (BHA), it can be concluded that isoferulic acid is an effective natural antioxidant in both lipid and aqueous media.     

<Emphasis Type="Italic">β</Emphasis>-Cyclodextrin as water-solubility enhancer for butylated hydroxytoluene

The phenomenon of the increase in solubility of the non-polar phenolic antioxidant — butylated hydroxytoluene (BHT) — in aqueous solutions containing β-cyclodextrin (CD) was studied. The complexation of BHT by CD was investigated using a phase solubility study. This method makes it possible to calculate the apparent formation constant for the host-guest complex. In addition, the thermodynamic properties were evaluated, revealing a spontaneous endothermic process of complex formation. Two solubility models were also used to verify their applicability to predicting the BHT concentration in solution. Those models included the modified Apelblat and Buchowski-Ksiazczak equations. In order to investigate the antioxidant properties of the BHT/CD/water ternary systems, a radical scavenging activity using a DPPH stable radical was performed. The experiments indicated that the antioxidant activity is temperature- and CD concentration-dependent. It was shown that complexation may inhibit the radical scavenging by BHT or change the scavenging stoichiometry.     

气相-质谱选择离子法测定化妆品中抗氧化剂丁基羟基茴香醚、二丁基羟基甲苯

 采用气相 质谱 (选择离子方式 )测定化妆品中抗氧化剂丁基羟基茴香醚 (BHA)和二丁基羟基甲苯(BHT) ,样品用甲醇振荡萃取 ,以SupelcoWAXTM 10 (30m× 0 2 5mmi.d .× 0 2 5 μm)为分析柱。该方法对样品中BHA和BHT的检测限分别为 2 5 μg/g和 0 5 μg/g。方法简便、快速、灵敏 ,可用于多种化妆品的检验。     

Antioxidant,Antidiabetic, Anticholinergic,and Antiglaucoma Effects of Magnofluorine

Magnofluorine, a secondary metabolite commonly found in various plants, has pharmacological potential; however, its antioxidant and enzyme inhibition effects have not been investigated. We investigated the antioxidant potential of Magnofluorine using bioanalytical assays with 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS^•+), N,N-dimethyl-p-phenylenediamine dihydrochloride (DMPD^•+), and 1,1-diphenyl-2-picrylhydrazyl (DPPH^•) scavenging abilities and K₃[Fe(CN)₆] and Cu²⁺ reduction abilities. Further, we compared the effects of Magnofluorine and butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), α-Tocopherol, and Trolox as positive antioxidant controls. According to the analysis results, Magnofluorine removed 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals with an IC₅₀ value of 10.58 μg/mL. The IC₅₀ values of BHA, BHT, Trolox, and α-Tocopherol were 10.10 μg/mL, 25.95 μg/mL, 7.059 μg/mL, and 11.31 μg/mL, respectively. Our results indicated that the DPPH· scavenging effect of Magnofluorine was similar to that of BHA, close to that of Trolox, and better than that of BHT and α-tocopherol. The inhibition effect of Magnofluorine was examined against enzymes, such as acetylcholinesterase (AChE), α-glycosidase, butyrylcholinesterase (BChE), and human carbonic anhydrase II (hCA II), which are linked to global disorders, such as diabetes, Alzheimer’s disease (AD), and glaucoma. Magnofluorine inhibited these metabolic enzymes with Ki values of 10.251.94, 5.991.79, 25.411.10, and 30.563.36 nM, respectively. Thus, Magnofluorine, which has been proven to be an antioxidant, antidiabetic, and anticholinergic in our study, can treat glaucoma. In addition, molecular docking was performed to understand the interactions between Magnofluorine and target enzymes BChE (D: 6T9P), hCA II (A:3HS4), AChE (B:4EY7), and α-glycosidase (C:5NN8). The results suggest that Magnofluorine may be an important compound in the transition from natural sources to industrial applications, especially new drugs.     

Purification and Identification of Novel Antioxidant Peptides from Enzymatically Hydrolysed Samia ricini Pupae

The emergence of excessive free radicals leads to the destruction of various systems within the body. These free radicals also affect nutritional values, color, taste, and emit an odor akin to rancid food. Most food industries use synthetic antioxidants, such as BHT (butylated hydroxytoluene) or BHA (butylated hydroxy anisole). However, high doses of these can be harmful to our health. Therefore, an antioxidant compounds, such as bioactive peptides from edible animals or plants, have emerged to be a very promising alternative as they reduce potential side effects. This study focused on the purification and identification of antioxidant peptides from protein hydrolysates of wild silkworm pupae (Samia ricini). Antioxidant peptides were purified from the hydrolysate by ultrafiltration and RP-HPLC. The results showed that protein hydrolysate from S. ricini pupae by trypsin with a molecular weight lower than 3 kDa and highly hydrophobic property, exhibited strong DPPH radical scavenging activity and chelating activity. Further identification of peptides from the fraction with the highest antioxidant activity was carried out using LC-MS/MS. Three novel peptides, i.e., Met-Ley-Ile-Ile-Ile-Met-Arg, Leu-Asn-Lys-Asp-Leu-Met-Arg, and Glu-Asn-Ile-Ile-Leu-Phe-Arg, were identified. The results of this study indicated that the protein hydrolysate from S. ricini pupae possessed potent biological activity, and the novel antioxidant peptides could be utilized to develop health-related antioxidants in food industry.     

In vivo anti-inflammatory and in vitro antioxidant activities of Moroccan medicinal plants

Five ethanol extracts of wild plants from the Casablanca region (Morocco) used in local traditional medicine for the treatment of inflammatory diseases were evaluated for their in vivo topical anti-inflammatory activity (inhibition of carrageenan-induced ear edema in mice) and in vitro antioxidant and antiradical properties (inhibition of linoleic acid oxidation, DPPH radical scavenging). All the extracts showed an anti-inflammatory effect: 300 microg/cm2 provoked edema reductions ranging from 22 to 28%. All the extracts also exerted radical scavenging and/or antioxidant properties, the most active plant being Mentha pulegium L. (Lamiaceae), which contained the highest amount of phenolics (339 mg/g), and flavonoids (16.7 mg/g).     

Synthesis and antioxidant activities of novel N‐aryl (and N‐alkyl) γ‐ and δ‐imino esters and ketimines

Novel N‐aryl (and N‐alkyl) γ‐ and δ‐imino esters 2a–g ( 3a–g ) and N‐aryl (and N‐alkyl) ketimines 2h–j ( 3h–j ) were synthesized in high yields (80–99%) from their corresponding γ‐ and δ‐keto esters and ketones in this study. The structures of the synthesized compounds were clarified by Fourier transform infrared (FT‐IR), NMR (¹H and ¹³C), mass spectrometry, and elemental analyses. Isomerizations [E/Z] were also determined by their ¹H NMR spectra. The free‐radical scavenging activity of imines was evaluated using the 1,1‐diphenyl‐2‐picryl‐hydrazyl (DPPH) method. The relationships between the structure and antioxidant activity of these compounds are discussed. Among these compounds, 2a–c (at the concentration 1000 μg/mL) exhibit high antioxidant activity similar to those of the standards (butylated hydroxyanisole [ BHA], butylated hydroxytoluene [ BHT], and ascorbic acid).     

Antiradical, chelating and antioxidant activities of hydroxamic acids and hydroxyureas

Reactive oxygen species, along with reactive nitrogen species, may play an important role in the pathogenesis and progress of many diseases, including cancer, diabetes and sickle cell disease. It has been postulated that hydroxyurea, one of the main treatments in sickle cell disease, achieves its activity partly also through its antioxidant properties. A series of hydroxyurea derivatives of L- and D-amino acid amides and cycloalkyl-N-aryl-hydroxamic acids was synthesized and investigated for their radical scavenging activity, chelating properties and antioxidant activity. All the compounds showed exceptional antiradical activities. For example, free radical scavenging activities of investigated hydroxyureas were higher than the activity of standard antioxidant, butylated hydroxyanisole (BHA). Moreover, most of the investigated hydroxamic acids were stronger Fe2? ion chelators than quercetin. In addition, the investigated compounds, especially hydroxamic acids, were proven to be excellent antioxidants. They were as effective as BHA in inhibiting β-carotene-linoleic acid coupled oxidation. It is reasonable to assume that the antioxidant activity of the investigated compounds could contribute to their previously proven biological properties as cytostatic and antiviral agents.     

Evaluation of the Antioxidant and Antiradical Properties of Some Phyto and Mammalian Lignans

In this study, the antioxidant and antiradical properties of some phyto lignans (nordihydroguaiaretic acid, secoisolariciresinol, secoisolariciresinol diglycoside, and α-(-)-conidendrin) and mammalian lignans (enterodiol and enterolactone) were examined by different antioxidant assays. For this purpose, radical scavenging activities of phyto and mammalian lignans were realized by 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) radical (ABTS^•+) scavenging assay and 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) scavenging assay. Additionally, the reducing ability of phyto and mammalian lignans were evaluated by cupric ions (Cu²⁺) reducing (CUPRAC) ability, and ferric ions (Fe³⁺) and [Fe³⁺-(TPTZ)2]³⁺ complex reducing (FRAP) abilities. Also, half maximal inhibitory concentration (IC₅₀) values were determined and reported for DPPH^• and ABTS^•+ scavenging influences of all of the lignan molecules. The absorbances of the lignans were found in the range of 0.150–2.320 for Fe³⁺ reducing, in the range of 0.040–2.090 for Cu²⁺ reducing, and in the range of 0.360–1.810 for the FRAP assay. On the other hand, the IC₅₀ values of phyto and mammalian lignans were determined in the ranges of 6.601–932.167 µg/mL for DPPH^• scavenging and 13.007–27.829 µg/mL for ABTS^•+ scavenging. In all of the used bioanalytical methods, phyto lignans, as secondary metabolites in plants, demonstrated considerably higher antioxidant activity compared to that of mammalian lignans. In addition, it was observed that enterodiol and enterolactone exhibited relatively weaker antioxidant activities when compared to phyto lignans or standard antioxidants, including butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), Trolox, and α-tocopherol.     

Screening of Carbonic Anhydrase,Acetylcholinesterase, Butyrylcholinesterase,and α-Glycosidase Enzyme Inhibition Effects and Antioxidant Activity of Coumestrol

Coumestrol (3,9-dihydroxy-6-benzofuran [3,2-c] chromenone) as a phytoestrogen and polyphenolic compound is a member of the Coumestans family and is quite common in plants. In this study, antiglaucoma, antidiabetic, anticholinergic, and antioxidant effects of Coumestrol were evaluated and compared with standards. To determine the antioxidant activity of coumestrol, several methods—namely N,N-dimethyl-p-phenylenediamine dihydrochloride radical (DMPD^•+)-scavenging activity, 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulphonate) radical (ABTS^•+)-scavenging activity, 1,1-diphenyl-2-picrylhydrazyl radical (DPPH^•)-scavenging activity, potassium ferric cyanide reduction ability, and cupric ion (Cu²⁺)-reducing activity—were performed. Butylated hydroxyanisole (BHA), Trolox, α-Tocopherol, and butylated hydroxytoluene (BHT) were used as the reference antioxidants for comparison. Coumestrol scavenged the DPPH radical with an IC₅₀ value of 25.95 μg/mL (r²: 0.9005) while BHA, BHT, Trolox, and α-Tocopherol demonstrated IC₅₀ values of 10.10, 25.95, 7.059, and 11.31 μg/mL, respectively. When these results evaluated, Coumestrol had similar DPPH^•-scavenging effect to BHT and lower better than Trolox, BHA and α-tocopherol. In addition, the inhibition effects of Coumestrol were tested against the metabolic enzymes acetylcholinesterase (AChE), butyrylcholinesterase (BChE), carbonic anhydrase II (CA II), and α-glycosidase, which are associated with some global diseases such as Alzheimer’s disease (AD), glaucoma, and diabetes. Coumestrol exhibited K_i values of 10.25 ± 1.94, 5.99 ± 1.79, 25.41 ± 1.10, and 30.56 ± 3.36 nM towards these enzymes, respectively.     

Separation and Determination of Phenolic Antioxidants by HPLC with Surfactant/n‐Propanol Mobile Phases

The influence of cationic and anionic surfactants and short‐chain alcohols in the mobile phase on the retention of five antioxidants has been studied. The solutes chosen were butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), and propyl, octyl, and dodecyl gallates (PG, OG, DG).The surfactants were hexadecyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS), and n‐propanol (PrOH) was the selected alcohol. A simple isocratic reversed‐phase method for the antioxidant determination is proposed. Separation of five primary antioxidants takes 18 min with the mobile phase SDS 0.10 M/H₃PO₄ 0.01 M/PrOH 30%. Variation of the percentage of alcohol in the mobile phase permits optimization of the retention times of the antioxidants. Detection limits in the pg range were obtained for the all solutes. The method was used to determine the antioxidants in olive oil at three different levels, giving mean recoveries close to 100% for all the solutes (BHA 102%, PG 99%, OG 99%, DG 99%) except BHT (84%).     

Isolation and characterization of 1,3-dicapryloyl-2-linoleoylglycerol: a novel triglyceride from berries of Hippophae rhamnoides

1,3-Dicapryloyl-2-linoleoylglycerol (1), a novel triglyceride, was isolated from berries of Hippophae rhamnoides. The structure was elucidated on the basis of MS, 1D and 2D NMR experiments including HMQC and HMBC. The metal chelating, free radical scavenging, and lipid peroxidation inhibiting properties of the compound were also estimated with particular reference to radiation protection. In case of metal chelation and superoxide ion scavenging, 1 showed maximum inhibition at 50 microg/ml (11%) and 100 microg/ml (55%), respectively, whereas in lipid peroxidation, 1 showed maximum inhibition (57%) at 2 mg/ml as compared to quercetin as a control.     

毛细管气相色谱法测定食用油中的酚类抗氧化剂BHA、BHT、TBHQ

建立了同时测定植物油中BHA、BHT、TBHQ等3种酚类抗氧化剂的测定方法。样品中的抗氧化剂经石油醚提取、乙腈萃取后采用HP-5毛细管柱分离。样品加标回收率为82.8?.6%,相对标准偏差为1.06%~3.11%,BHA、BHT、TBHQ的最低检出量分别为5、10、5ng。该方法具有快速、灵敏度高、重现性好、前处理简单等优点。