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1.
Abdalbasit Adam Mariod Ramlah Mohamad Ibrahim Maznah Ismail Norsharina Ismail 《Journal of the American Oil Chemists' Society》2010,87(1):35-43
The total phenolic content and the antioxidant potential of methanolic extract (ME), ethyl acetate extract (EAE), and hexane
extract (HE) from Monechma ciliatum leaves (MCL) were evaluated. The Folin-Ciocalteu, β-carotene bleaching, the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical
scavenging and the accelerated oxidation methods were used for evaluation. Both the extraction yield and the antioxidant activity
(AOA) were strongly dependent on the solvent. Among the extracts, ME exhibited highest total phenolic compounds (TPC) and
IC50 values for DPPH, followed by EAE and HE, respectively. Peroxide value (PV), anisidine value (AV) conjugated dienes (CD),
and thiobarbituric acid reactive substances (TBARS) were taken as the parameters for evaluation of stabilization efficacy
of MCL extracts and results revealed MCL to be a potent antioxidant for the stabilization of corn oil. As a general trend,
increased AOA was observed for increased extract concentration. The predominant phenolic compounds identified by HPLC-DAD
in MCL extracts were p-coumaric acid, vanillin and ferulic acid. 相似文献
2.
Louis Pergaud Sandjo Abdou Tchoukoua Hippolyte Nga Ntede Mehdi Yemloul Enrico Perspicace Felix Keumedjio François Couty Gilbert Kirsch Bonaventure Tchaleu Ngadjui 《Journal of the American Oil Chemists' Society》2010,87(10):1167-1177
To highlight the role of plants in traditional healing, the leaves and the stems of cultivated Triumfetta cordifolia were phytochemically studied yielding a new nor-ursane type (1), a new ceramide (2) and a new piperidinic ceramide derivative (3) named, respectively, 2α,19α-dihydroxy-3-oxo-23-nor-urs-12-en-28-oic acid, (2R)-2-hydroxy-N-[(2S,3S,4R,26E)-1,3,4-trihydroxy-26-triaconten-2-yl] tetradecanamide and (2R,8Z)-2-hydroxy-{(2S,3R,5R,6S)-3,5-dihydroxy-6-[(1E,5Z)-hexadeca-1,5-dienyl]-2-(β-d-glucopyranosyloxy)methyl piperidine-1-yl} tetracos-8-enamide (3). These were obtained together with lupeol (4), stigmasterol (5), 3-O-β-d-glucopyranoside of β-sitosterol (6), tormentic acid (7) from stems and heptadecanoic acid (8), β-carotene (9), oleanolic acid (10), and 24-hydroxytormentic acid (11) from leaves. The structures were determined on the basis of NMR data (1H-, 13C-, 2D-NMR analyses), mass spectrometry and confirmed by chemical transformations as well as comparison of spectral data with
those reported in the literature. The FRAP method was used to evaluate the antioxidant activity of fractions collected from
flash chromatography and isolated compounds. Among the fractions, four reduced FeIII-TPTZ to FeII-TPTZ while isolated pure compounds showed no activity. 相似文献
3.
The antioxidant activity of crude tannins of canola and rapeseed hulls was evaluated by β-carotene-linoleate, α,α-diphenyl-β-picrylhydrazyl
(DPPH) radical, and reducing power assays. Crude tannins were extracted from three samples of Cyclone canola (high-tannin)
hulls and Kolner, Ligaret, and Leo Polish rapeseed (low-tannin) hulls with 70% (vol/vol) acetone. The total phenolic content
in crude tannin extracts ranged between 128 and 296 mg of sinapic acid equivalents per 1 g of extract. The ultraviolet spectra
of methanolic solution of canola extracts showed two absorption maxima (282 and 309 nm), whereas those of rapeseed extracts
exhibited a single maximum (326 nm). Crude tannins isolated from canola hulls exerted significantly (P<0.025) greater antioxidant activity than those from rapeseed in all three assays. The scavenging effect of all crude tannins,
at a dose of 1 mg, on the DPPH radical ranged from 35.2 to 50.5%. The reducing power of Cyclone canola hull extracts on potassium
ferricyanide was significantly (P≤0.0025) greater than that of rapeseed hull extracts, and the observed data correlated well (r=0.966; P=0.002) with the total content of phenolics present. 相似文献
4.
Novel ceramides and a new glucoceramide from the roots of <Emphasis Type="Italic">Incarvillea arguta</Emphasis> 总被引:3,自引:0,他引:3
Novel ceramides, rel-(3S,4S,5S)-3-[(2R)-2-hydroxycosanoyl-hexacosanoylamino]-4-hydroxy-5-[(4Z)-tetradecane-4-ene]-2,3,4,5-tetrahydrofuran (1a-g), and a new glucoceramide, 1-O-β-d-glucopyranosyl-(2S,3S,4R,8E)-2-[(2R)-2-hydroxytetracosanoylamino]-1,3,4-octodecanetriol-8-ene (2) were isolated from the aqueous ethanolic extract of the roots of Incarvillea arguta, together with eight known compounds: β-sitosterol (3), oleanolic acid (4), ursolic acid (5), piperin (6), maslinic acid (7), β-sitosterol 6′-O-acyl-β-d-glucopyranoside (8), 8-epideoxyloganic acid (9), and plantarenaloside (10). Their structures were elucidated on the basis of spectral data including IR, MS, NMR [1H NMR, 13C NMR (distortionless enhancement by polarization transfer), 1H−1H COSY, heteronuclear multiplequantum coherence, and heteronuclear multiple-bond coherence correlations]. The relative configurations
were established by nuclear Overhauser effect spectroscopy experiments and by comparison of the NMR spectral data and coupling
constants with those already reported in the literature. 相似文献
5.
An-Ling Zhang Li-Ying He Jin-Ming Gao Xu Xu Shi-Qing Li Ming-Sheng Bai Jian-Chun Qin 《Lipids》2009,44(8):745-751
Two new natural compounds, a symmetrical disulfide dimer didodecyl 3,3″-dithiodipropionate (1) and a pregnane steroid 5,16-pregnadien-3β-ol-20-one acetate (2), were isolated together with two known compounds, ergosta-4,6,8(14),22-tetraen-3-one (3) and ergosterol peroxide (4), from the ethyl acetate soluble extract of fermentation broth of an endophytic fungus, Sphaceloma sp. LN-15 isolated from the leaves of Melia azedarach L. and grown in pure culture. Their structures were determined on the basis of spectroscopic methods including 1D and 2D
nuclear magnetic resonance spectroscopy (NMR) experiments and by mass spectrometric measurements (MS). These fungal metabolites
were isolated for the first time from the genus Sphaceloma. The structure of 1 was also confirmed by chemical synthesis. 相似文献
6.
Antioxidant activity of burdock (Arctium lappa Linné): Its scavenging effect on free-radical and active oxygen 总被引:1,自引:0,他引:1
Pin-Der Duh 《Journal of the American Oil Chemists' Society》1998,75(4):455-461
The antioxidant activity and free-radical and active oxygen-scavenging activity of burdock extracts were investigated. Of
the solvents used for extraction, water yielded the greatest amount of extract that exhibited the strongest antioxidant activity.
Water extracts of burdock (WEB) and hot water extracts of burdock (HWEB) exhibited comparable and marked activity on inhibition
of linoleic acid peroxidation, indicating that heat treatment did not alter the antioxidant activity of WEB. WEB and HWEB
produced significantly lower (P<0.05) malondialdehyde (MDA) in both linoleic acid and liposome model systems than did the control. Moreover, mixtures of
tocopherol (Toc), WEB, and HWEB exhibited a remarkable synergistic antioxidant effect in a liposome system; WEB and HWEB thus
potentiated the action of Toc. Furthermore, WEB and HWEB displayed a marked inhibitory effect on lipid peroxidation of rat
liver homogenate in vitro. WEB and HWEB exhibited an 80% scavenging effect on α,α-diphenyl-β-picrylhydrazyl radical and marked reducing power, indicating
that WEB and HWEB act as primary antioxidants. Both extracts at a dose of 1.0 mg exhibited a 60.4–65.0% scavenging effect
on superoxide and an 80.5% scavenging effect on hydrogen peroxide. They also showed a marked scavenging effect on the hydroxyl
radical. These results revealed that WEB and HWEB are also active as oxygen scavengers and as secondary antioxidants. Based
on these results, termination of free-radical reactions and quenching of reactive oxygen species in burdock extracts are suggested
to be, in part, responsible for the antioxidant activity of burdock extracts. 相似文献
7.
Purification and Characterization of a Radical Scavenging Peptide from Rapeseed Protein Hydrolysates 总被引:1,自引:0,他引:1
Shao Bing Zhang Zhang Wang Shi Ying Xu Xian Fu Gao 《Journal of the American Oil Chemists' Society》2009,86(10):959-966
We previously reported that crude rapeseed peptides (CRPs) and peptide fractions (RP25 and RP55) prepared from aqueous enzymatic
extraction of rapeseed exhibited marked antioxidant activities, among which RP55 showed the most potent effects. In the present
study, RP55 was further purified using consecutive chromatographic methods for identification of antioxidant peptides. The
α,α-diphenyl-β-picrylhydrazyl (DPPH) radical scavenging effects of peptides were measured at each purification step to evaluate
the antioxidant activities. RP55 was first fractionated by anion-exchange chromatography, and three fractions (E1, E2, and
E3) were obtained. All of them showed significantly lower scavenging activities compared to RP55, which was very probably
due to the remarkable loss of tannin during the separation. Next, the active fraction E2 with higher protein content was sequentially
purified by gel filtration chromatography (GFC) and reversed-phase high performance liquid chromatography (RP-HPLC). The purified
peptide, of which the median effective dose (ED50) value for DPPH radical scavenging was 0.063 mg/mL, was identified to be Pro-Ala-Gly-Pro-Phe (487 Da) using electrospray
ionization (ESI) mass spectrometry. The unique amino acid composition and sequence in the peptide might play an important
role in expression of its antioxidant activity. 相似文献
8.
采用清除二苯代苦味酰基(DPPH)自由基、清除[2,2′-连氨-(3-乙基苯并噻唑啉-6-磺酸)]二氨盐(ABTS)自由基和铁离子还原/抗氧化能力(FRAP)测定法对其挥发油和不同提取物进行抗氧化活性的研究。结果表明,生苍术乙酸乙酯提取物具有很好的抗氧化活性(DPPH方法:IC50=6.03μg/mL;ABTS方法:IC50=3.59μg/mL;FRAP方法:FRAP值=3186.67μmolTE/g),麸炒之后,其抗氧化活性显著下降。因而苍术抗氧化应生用。 相似文献
9.
Niger (Guizotia abyssinica) seed was ground and then defatted with hexane. The meal remaining after oil extraction was tested as a source of antioxidants.
Three solvent systems, A [80∶20 (vol/vol) ethanol/water], B [80∶20 (vol/vol) acetone/water], and C (water) were evaluated
as extraction media. Crude extracts were examined for their antioxidant activity in a β-carotene-linoleate and a meat model
system. Extract A exhibited superior antioxidant activity, compared to extracts B and C, and its composition was studied further
by using column chromatography and HPLC. Four fractions (I–IV) were obtained, of which fractions III and IV showed activity
in the β-carotene-linoleate model system. Fraction IV was also highly effective in scavenging the 2,2-diphenyl-1-picrylhydrazyl
radical but was less active when used in a bulk oil model system. Preparative TLC showed fraction IV as consisting of two
components. UV spectroscopy suggested that the major active component pressent was a chlorogenic acid-related compound. Furthermore,
HPLC analysis established that chlorogenic acid was dominant in the free phenolics fraction (2.6 mg/g). Upon hydrolysis, however,
a substantial amount of caffeic acid (42.8 mg/g) was released, presumably from esterified and glycosylated chlorogenic acid.
Thus, niger extracts derive their antioxidant activity, at least in part, from the chlorogenic acid-related compounds. 相似文献
10.
Ramesh N. Patel Ronald L. Hanson Amit Banerjee Laszlo J. Szarka 《Journal of the American Oil Chemists' Society》1997,74(11):1345-1360
Chiral intermediates were prepared by biocatalytic processes with oxidoreductases for the chemical synthesis of some pharmaceutical
drug candidates. These include: (i) the microbial reduction of 1-(4-fluorophenyl)-4-[4-(5-fluoro-2-pyrimidinyl)-1-piperazinyl]-1-butanone
(1) to R-(+)-1-(4-fluorophenyl)-4-[4-(5-fluoro-2-pyrimidinyl)-1-piperazinyl]-1-butanol (2) [R-(+)-BMY 14802], an antipsychotic agent; (ii) the reduction of N-4-(1-oxo-2-chloroacetyl ethyl) phenyl methane sulfonamide (3) to the corresponding chiral alcohol (4), an intermediate for d-(+)-N-4-{1-hydroxy-2-[(-methylethyl)amino]ethyl}phenyl methanesulfonamide [d-(+) sotalol], a β-blocker with class III antiarrhythmic properties; (iii) biotransformation of Nɛ-carbobenzoxy (CBZ)-l-lysine (7) to Nɛ-CBZ-l-oxylysine (5), an intermediate needed for synthesis of (S)-1-[6-amino-2-{[hydroxy(4-phenylbutyl)phosphinyl]oxy}1-oxohexyl]-l-proline (ceronapril), a new angiotensin converting enzyme inhibitor (6) and (iv) enzymatic synthesis of l-β-hydroxyvaline (9) from α-keto-β-hydroxyisovalerate (16). l-β-Hydroxyvaline (9) is a key chiral intermediate needed for the synthesis of S-(Z)-{[1-(2-amino-4-thiazolyl)-2-{[2,2-dimethyl-4-oxo-1-(sulfooxy)-3-azetidinyl] amino}-2-oxoethylidene]amino}oxyacetic acid
(tigemonam) (10), an orally active monobactam. 相似文献
11.
The banded sunflower moth (BSFM), Cochylis hospes Walshingham (Lepidoptera: Cochylidae) is a specialist insect, the larvae of which feed on sunflowers, Helianthus spp., and a few other species of Compositae. It is one of the most important pests of sunflower in the USA. Previous work
on H. annuus, the cultivated sunflower, revealed two diterpenoids that function as oviposition stimulants for female BSFM, and that other,
more polar compounds also stimulated oviposition. Using a bioassay-guided approach, we isolated three additional diterpenoids,
grandifloric acid (1), 15β-hydroxy-ent-trachyloban-19-oic acid (2), and 17-hydroxy-16α-ent-kauran-19-oic acid (3), from polar fractions of pre-bloom sunflower head extracts. In laboratory bioassays, purified natural samples of each of
these compounds stimulated oviposition by female BSFM. Structure–activity relationships of the five diterpenoids known to
stimulate oviposition by female BSFM are discussed. 相似文献
12.
G Garrote J
M Cruz H Domínguez J
C Paraj 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2003,78(4):392-398
Non‐isothermal processing of lignocellulosic materials in aqueous media (autohydrolysis reaction) under mild conditions leads to solutions containing valuable chemicals (oligosaccharides, sugars and acetic acid) and other, undesired, compounds (belonging to the extractive and acid‐soluble lignin fractions) which have to be removed in further purification treatments. Liquors obtained by non‐isothermal autohydrolysis of Eucalyptus globulus wood and corncobs under a variety of operational conditions were extracted with ethyl acetate in order to remove non‐saccharide components, and the suitability of the fraction dissolved in the organic phase was assayed for possible utilisation as an antioxidant. The yield and antioxidant activity of ethyl acetate extracts (measured by the α,α‐diphenyl‐β‐picrylhydrazyl (DPPH) radical scavenging capacity) showed a strong dependence on the autohydrolysis conditions. The antioxidant activity of extracts obtained under selected operational conditions compared well with synthetic antioxidants. © 2003 Society of Chemical Industry 相似文献
13.
The antioxidant activities of 70% acetone extract (70% AE) from the hypocotyls of the mangrove plant Kandelia candel and its fractions of petroleum ether (PF), ethyl acetate (EF), water (WF), and the LF (WF fraction further purified through a Sephadex LH-20 column), were investigated by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging and ferric reducing/antioxidant power (FRAP) assays. The results showed that all the extract and fractions possessed potent antioxidant activity. There was a significant linear correlation between the total phenolics concentration and the ferric reducing power or free radical scavenging activity of the extract and fractions. Among the extract and fractions, the LF fraction exhibits the best antioxidant performance. The MALDT-TOF MS and HPLC analyses revealed that the phenolic compounds associated with the antioxidant activity of the LF fraction contains a large number of procyanidins and a small amount of prodelphinidins, and the epicatechin is the main extension unit. 相似文献
14.
Norihisa Kusumoto Tatsuya Ashitani Yuichi Hayasaka Tetsuya Murayama Koichi Ogiyama Koetsu Takahashi 《Journal of chemical ecology》2009,35(6):635-642
Eight known abietane-type diterpenes were isolated from the weak acidic fraction of the n-hexane extract from cones of Taxodium distichum, one of the extant, living fossil conifers. They were identified as 6,7-dehydroroyleanone (1), taxodal (2), taxodione (3), salvinolone (4), 14-deoxycoleon U (5), 5,6-dehydrosugiol (6), sandaracopimaric acid (7), and xanthoperol (8). The structures of these compounds were determined by comparison of NMR spectral data with published data. The antitermitic
(termicidal and antifeedant) activities of the compounds 1–8 against the subterranean termite, Reticulitermes speratus Kolbe, were evaluated. Compounds 1 and 3 showed potent termicidal activity, and 5 and 8 showed potent antifeedant activity. Compound 1 was found to be one of the representative bioactive compounds in the n-hexane extract of T. distichum cones. Compounds 1–8, with the exception of 7, were oxides of ferruginol (9). Therefore, the presence of various oxidation forms of the abietane-type structure reflects their various bioactivities. 相似文献
15.
粘毛蓼的抗氧化活性 总被引:1,自引:0,他引:1
用清除二苯代苦味酰基(DPPH)自由基、清除[2,2′-连氨-(3-乙基苯并噻唑啉-6-磺酸)二氨盐](ABTS)自由基和铁离子还原/抗氧化能力(FRAP)测定法,对粘毛蓼体外总抗氧化活性进行了评价,结果与6-羟基-2,5,7,8-四甲基苯并二氢吡喃-2-羧酸(Trolox)及阳性对照丁基羟基茴香醚(BHA)、二丁基羟基甲苯(BHT)比较发现,粘毛蓼提取物有很好的体外抗氧化活性。乙酸乙酯提取物清除DPPH自由基(IC50=7.89 mg/L)的能力比BHT清除能力(IC50=18.71 mg/L)强,比BHA(IC50=3.20 mg/L)清除能力略弱;清除ABTS自由基能力(IC50=6.67 mg/L)比BHT(IC50=7.72 mg/L)清除能力强,比BHA(IC50=1.88 mg/L)清除能力弱;还原Fe3+的能力〔FRAP=(1362.55±47.22)μmol TE/g〕比BHT〔FRAP=(1581.68±97.41)μmol TE/g〕略低。在3种提取物中,乙酸乙酯提取物具有最高的抗氧化能力,甲醇提取物次之。3种方法中,DPPH方法和ABTS方法相关性最高(R=0.993)。 相似文献
16.
Samia Dabbou Faten Brahmi Ameni Taamali Manel Issaoui Youssef Ouni Mohamed Braham Mokhtar Zarrouk Mohamed Hammami 《Journal of the American Oil Chemists' Society》2010,87(10):1199-1209
The effects of the contents of lipids, pigments, α-tocopherol and phenols were studied in relation to the antioxidant capacity
of five virgin olive oils obtained from five olive cultivars planted in Tunisia (Arbequina, Koroneiki, Leccino, Oueslati and
Chemchali). The antioxidant capacities were evaluated by two different radical scavenging activities: radical scavenging activity
by the DPPH assay (RSA-DPPH) and total antioxidant status by the ABTS test (TAA-ABTS). The highest contents of antioxidant
compounds (75.96, 10.34, 6.32, 15.39 and 241.52 mg kg−1 for oleic acid, O/L ratio, carotenes, chlorophylls and total phenols, respectively) were found for the Koroneiki cultivar
except for α-tocopherol and o-diphenols, which had the highest contents (369 and 160.7 mg kg−1, respectively) in the Leccino and Chemchali cultivars (cvs). Furthermore, the highest antioxidant capacity in virgin olive
oil was observed in the Koroneiki cultivar (0.24 mmol TE kg−1) followed by the Chemchali and Leccino cvs (0.22 and 0.13 mmol TE kg−1) for the TAA-ABTS test. However, the RSA-DPPH activity was higher for the Chemchali cultivar (19.9%) than for the Koroneiki
and Leccino cvs (18.4 and 13.5%, respectively). Correlation between these capacities and the oil composition revealed that
they were mainly influenced by the carotene content, followed by chlorophyll and phenolic contents where the ABTS test was
more pronounced. Then, the antioxidant capacity of the virgin olive oils was correlated with polar components and the lipid
profile which are important for its shelf life. 相似文献
17.
Mohamed Fawzy Ramadan S. G. Kinni M. Seshagiri Jörg-Thomas Mörsel 《Journal of the American Oil Chemists' Society》2010,87(8):885-894
Semecarpus anacardium (family Anacardiaceae) has many applications in the Ayurvedic and Siddha systems of medicine in India. Detailed knowledge on the composition of S. anacardium oil, in consideration of potential utilization, is of major importance. In this investigation, column chromatography, gas
chromatography, thin layer chromatography and liquid chromatography techniques were performed to analyze lipid classes, fatty
acids and fat-soluble bioactives of S. anacardium crude seed oil. The amount of neutral lipids in the crude seed oil was the highest, followed by glycolipids and phospholipids,
respectively. Linoleic followed by palmitic and oleic were the major fatty acids. The ratio of unsaturated fatty acids to
saturated fatty acids was higher in neutral lipid classes than in the polar lipids. The main sterol compounds were β-sitosterol,
campesterol and stigmasterol. δ-Tocopherol followed by β-tocopherol were the main tocopherols. When S. anacardium seed oil and extra virgin olive oil were compared for their radical scavenging activity toward 1,1-diphenyl-2-picrylhydrazyl
radical and galvinoxyl radical (by electron spin resonance spectrometry), S. anacardium seed oil exhibited a stronger RSA. 相似文献
18.
Ana M. Romero Mirtha M. Doval Mario A. Sturla Maria A. Judis 《European Journal of Lipid Science and Technology》2004,106(7):424-431
The antioxidant properties and total phenolic compounds of soybean extract fermented with Saccharomyces cerevisiae during 24 h were evaluated. Total polyphenolic compounds extracted in ethanol/water (1:1) solution were 789.54 mg/g dry extract, and flavonoids were 169.47 mg quercetin equivalents/g of dry extract. Reducing power (91.18%) and DPPH scavenging (79.30% at 4‐times diluted) were excellent, and so high as BHA, 92.17% and 73.8% respectively, while superoxide anion scavenging showed poor inhibition (4876 equivalent SOD U/g). Antioxidant activity in linoleic acid/water emulsion system of fermented extract measured as peroxide formation inhibition at 37 °C was the strongest (95.62%), while it exerted a moderate inhibition for conjugated dienes and thiobarbituric acid reactive substances (64.77% and 54.33%). At 80 °C the antioxidant activity assayed at a higher concentration was less effective (29.35% on CD; 74.58% on PV and 35.04% on TBARS). 相似文献
19.
Masahiro Ogata Midori Hoshi Kumiko Shimotohno Shiro Urano Toyoshige Endo 《Journal of the American Oil Chemists' Society》1997,74(5):557-562
The antioxidant activity of 10 Japanese and Chinese crude drugs (Kampo drugs) was determined in vitro. Extract of Magnolia cortex, which had the highest antioxidant activity, contained phenolic compounds magnolol and honokiol. However, inhibitory effects
of these compounds on lipid oxidation were weaker than that of α-tocopherol as measured by thiobarbituric acid assay. The
structure-activity relationship of phenolic compounds showed that antioxidant activities were in the order 4-allyl-2,6-dimethoxyphenol
≥ p,p′-biphenol > eugenol > 2-allyl-6-methylphenol > honokiol > magnolol > caffeic acid > p-ethylphenol > guaiacol. As expected, these results showed that an electron donor and/or bulky groups at the ortho- or para-position of the phenol were required for inhibition of lipid oxidation. Electron spin resonance spin trapping experiments
showed that phenol compounds with an allyl substituent on their aromatic rings directly scavenged superoxide (O
2
−
), and that only eugenol trapped hydroxyl radicals. These findings suggest that phenolic compounds that contain allyl groups
may be effective antioxidants because of the scavenging ability of O
2
−
or hydroxyl radical, whereas other phenols, without an allyl moiety such as α-tocopherol, may play a role in the termination
of free radical chain reactions. 相似文献