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1.
Both selenium and phycocyanin have been reported to show potent cancer chemopreventive activities. In this study, we investigated the in vitro antioxidant and antiproliferative activities of selenium-containing phycocyanin (Se-PC) purified from selenium-enriched Spirulina platensis. The antioxidant activity of Se-PC was evaluated by using four different free radical scavenging assays, namely, the 2,2'-azinobis-3-ethylbenzothiazolin-6-sulfonic acid (ABTS) assay, 1,1-diphenyl-2-picryhydrazyl (DPPH) assay, superoxide anion scavenging assay, and erythrocyte hemolysis assay. The results indicated that Se-PC exhibited stronger antioxidant activity than phycocyanin by scavenging ABTS, DPPH, superoxide anion, and 2,2'-azobis-(2-amidinopropane)dihydrochloride free radicals. Se-PC also showed dose-dependent protective effects on erythrocytes against H 2O 2-induced oxidative DNA damage as evaluated by the Comet assay. Moreover, Se-PC was identified as a potent antiproliferative agent against human melanoma A375 cells and human breast adenocarcinoma MCF-7 cells. Induction of apoptosis in both A375 and MCF-7 cells by Se-PC was evidenced by accumulation of sub-G1 cell populations, DNA fragmentation, and nuclear condensation. Further investigation on intracellular mechanisms indicated that depletion of mitochondrial membrane potential (DeltaPsi m) was involved in Se-PC-induced cell apoptosis. Our findings suggest that Se-PC is a promising organic Se species with potential applications in cancer chemoprevention.  相似文献   

2.
Vitamin C equivalent antioxidant capacity (VCEAC) of phenolic phytochemicals   总被引：11，自引：0，他引：11  
To express the antioxidant capacity of plant foods in a more familiar and easily understood manner (equivalent to vitamin C mg/100 g), two stable radical species, ABTS(*)(-) and DPPH(*), commonly used for antioxidant activity measurements, were employed independently to evaluate their efficacies using apple polyphenolic extracts and seven polyphenolic standards including synthetic Trolox. Their antioxidant activities were expressed as vitamin C equivalent antioxidant capacity (VCEAC) in mg/100 g apple or mg/100 mL of the reference chemical compounds in 10 and 30 min using the ABTS(*)(-) and DPPH(*) scavenging assays, respectively. The antioxidant capacity of Gala apples and seven phenolic standards, determined by both ABTS(*)(-) and DPPH(*) scavenging assays, showed a dose-response of the first-order. Fresh Gala apples had a VCEAC of 205.4 +/- 5.6 mg/100 g using the ABTS assay, and the relative VCEACs of phenolic standards were as follows: gallic acid > quercetin > epicatechin > catechin > vitamin C > rutin > chlorogenic acid > Trolox. With the DPPH radical assay, the VCEAC of fresh Gala apples was 136.0 +/- 6.6 mg/100 g, and the relative VCEACs of seven phenolic standards were, in decreasing order, as follows: gallic acid > quercetin > epicatechin > catechin > or = vitamin C > Trolox > rutin > chlorogenic acid. Because the ABTS assay can be used in both organic and aqueous solvent systems, employs a specific absorbance at a wavelength remote from the visible region, and requires a short reaction time, it is a more desirable method than the DPPH assay. Therefore, it is recommended that antioxidant capacity be expressed as vitamin C mg/100 g equivalent (VCEAC) using the ABTS assay.  相似文献   

3.
The protein from the seeds of melinjo ( Gnetum gnemon ) was purified using a precipitation method and ion exchange chromatographic techniques to identify the potent antioxidant and free radical scavenging activities. Two antioxidant protein fractions were isolated from G. gnemon seed with molecular weights of approximately 30 kDa (Gg-AOPI) and 12 kDa (Gg-AOPII) by SDS-PAGE. The N-terminal amino acid sequence of Gg-AOPII is Gly-Asn-Gly-Lys-Ala-Thr-Val-Ala-Ile-Leu-Val-Lys-Glu-Lys-Val-Glu-Tyr-Gly-Glu-Glu, and the result of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) analysis showed that they were distinct from each other; no protein in database matching was found to both Gg-AOPI and Gg-AOPII. The antioxidant or free radical scavenging activities of Gg-AOPs were investigated by employing in vitro assay systems including the inhibition of linoleic acid autoxidation, scavenging effect on α,α-diphenyl-β-picrylhydrazyl free radical (DPPH), 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), reducing power, chelating abilities of metal ions Cu(2+) and Fe(2+), and protections against hydroxyl radical-mediated DNA damages. The result showed that two protein fractions exhibited significant (p < 0.05) antioxidant activities against free radicals such as DPPH, ABTS, and superoxide anion and showed activities similar to those of glutathione (G-SH) and BHT in a linoleic acid emulsion assay system. Moreover, Gg-AOPI and Gg-AOPII also exhibited notable reducing power and strong chelating effect on Fe(2+) and protected hydroxyl radical induced oxidative DNA damage. The data obtained by the in vitro systems obviously established the antioxidant potency of Gg-AOPs.  相似文献   

4.
The extract of soybean exposed to biotic elicitors such as food-grade fungus is known to have antioxidant activity. Glyceollins were major bioactive compounds present in soybean elicited by fungi and shown to have antifungal and anticancer activities. The purpose of present study was to evaluate the antioxidant activities of glyceollins by measuring ferric reducing antioxidant power (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, singlet oxygen quenching, 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging, hydroxyl radical scavenging activity, and lipid peroxidation inhibition. In addition, the antioxidant potential of glyceollins were measured by a fluorescent probe, 2',7'-dichlorofluorescin diacetate (DCFDA), and dihydroethidium (DHE) in mouse hepatoma hepa1c1c7 cells in which they were insulted with H2O2 to generate reactive oxygen species (ROS). Glyceollins showed a strong reducing power and inhibited lipid peroxidation, with significant scavenging activities of radicals including singlet oxygen, superoxide anion, ABTS, and DPPH. We also found that glyceollins significantly suppressed H2O2-induced ROS production in hepa1c1c7 cells. Therefore, glyceollins deserve further study as natural antioxidants and nutraceuticals.  相似文献   

5.
Black tea, green tea, red wine, and cocoa are high in phenolic phytochemicals, among which theaflavin, epigallocatechin gallate, resveratrol, and procyanidin, respectively, have been extensively investigated due to their possible role as chemopreventive agents based on their antioxidant capacities. The present study compared the phenolic and flavonoid contents and total antioxidant capacities of cocoa, black tea, green tea, and red wine. Cocoa contained much higher levels of total phenolics (611 mg of gallic acid equivalents, GAE) and flavonoids (564 mg of epicatechin equivalents, ECE) per serving than black tea (124 mg of GAE and 34 mg of ECE, respectively), green tea (165 mg of GAE and 47 mg of ECE), and red wine (340 mg of GAE and 163 mg of ECE). Total antioxidant activities were measured using the 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assays and are expressed as vitamin C equivalent antioxidant capacities (VCEACs). Cocoa exhibited the highest antioxidant activity among the samples in ABTS and DPPH assays, with VCEACs of 1128 and 836 mg/serving, respectively. The relative total antioxidant capacities of the samples in both assays were as follows in decreasing order: cocoa > red wine > green tea > black tea. The total antioxidant capacities from ABTS and DPPH assays were highly correlated with phenolic content (r2 = 0.981 and 0.967, respectively) and flavonoid content (r2 = 0.949 and 0.915). These results suggest that cocoa is more beneficial to health than teas and red wine in terms of its higher antioxidant capacity.  相似文献   

6.
This paper reports the use of spectrophotometric and voltammetric methods for the determination of the antioxidant capacity of buckwheat and its products originated from a technological line of a buckwheat roasted groats producer. 80% methanol extracts from raw and roasted buckwheat and groats and hulls obtained from roasted buckwheat were used. The spectrophotometric methods included (1) free radical scavenging activities of the extracts against ABTS*+ radical cation (TEAC) and 2,2-diphenyl-1-picrylhydrazyl radical (DPPH RSA) and (2) determination of reducing capacity by the means of Folin-Ciocalteu reagent (FCR) application. The radical scavenging activities of the extracts were also investigated using a voltammetric assay. Moreover, the flavonoids profiles of the studied materials were provided. Buckwheat roasting caused a decrease in TEAC, DPPH RSA, and FCR reducing capacity by 70%. The lowest TEAC, DPPH RSA, and FCR reducing capacities were noted for roasted groats. Both DPPH RSA and TEAC methods were highly positively correlated with the FCR reducing capacity assay (r = 0.98 and r = 0.99). Cyclic voltammograms of analyzed buckwheat extracts were useful for evaluation of the antioxidant capacity. The total charge below the anodic current waveform was correlated with the data obtained by TEAC (r = 0.770), DPPH RSA (r = 0.88), and FCR reducing capacity (r = 0.81). The changes in the antioxidant capacity of buckwheat and its products followed the changes in flavonoids composition. In particular, the concentration of flavonoids was related to measurements by cyclic voltammetry.  相似文献   

7.
Bran extracts of Akron wheat grown at four nonirrigated and one irrigated testing locations were examined and compared for their free radical scavenging properties against the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH(*)) and the radical cation ABTS(*)(+), chelating capacities, and total phenolic content (TPC) to determine the potential effects of environmental factors on the antioxidant properties of hard winter wheat. The environmental factors included total solar radiation, average daily solar radiation, and number of hours exceeding 32 degrees C. The results showed that bran samples from different growing locations may significantly differ in their radical scavenging activities against both DPPH(*) and ABTS(*)(+), chelating capacities, and TPC. A significant negative correlation was detected between the chelating activities of the bran samples from the four nonirrigated locations and total solar or daily average solar radiation (r = -0.999 and P = 0.001). These data suggest potential influences of growing conditions on the antioxidant properties of hard winter wheat and the possibility of producing wheat that is strong in a selected antioxidant property by optimizing the growing conditions of a selected wheat variety. More research is required to further investigate the relationship among antioxidant properties and environmental factors using different wheat varieties and larger sample sizes.  相似文献   

8.
Geranium niveum S. Watson (Geraniaceae) is a medicinal herb widely used by the Tarahumara Indians of Mexico. This species is rich in proanthocyanidins and other phenolics. Previous in vitro assays have demonstrated that proanthocyanidins exhibited antiinflammatory, antiviral, antibacterial, enzyme-inhibiting, antioxidant, and radical-scavenging properties. In view of its medicinal use and chemical composition, the aim of the present study was to determine the in vitro antioxidant activity of the extracts and two proanthocyanidins (geranins A and D) from the roots of G. niveum by using seven different assay systems, namely, 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), 1,1-diphenyl-2-picrylhydrazyl (DPPH), superoxide anion (O2*-), hydrogen peroxide (H2O2), hydroxyl radical (OH*), hypochlorous acid (HOCl), and singlet oxygen ((1)O2). Two known antioxidants, resveratrol and ascorbic acid, were used as positive controls. The results showed that geranins A and D and the extracts were able to scavenge ABTS, DPPH, O2*-, OH*, and HOCl. The scavenging ability of geranins A and D was similar to that of resveratrol and ascorbic acid in the following assays: ABTS, O2*-, and HOCl. The scavenging capacity of ascorbic acid for DPPH was higher than that of both geranins and resveratrol. On the other hand, the OH* scavenging action of both geranins and resveratrol was similar. The methanol-CHCl3 (1:1) extract had a higher ability to scavenge ABTS, DPPH, and O2*- radicals than the chloroform extract. In turn, the latter was more potent than the methanol-CHCl3 (1:1) extract as OH* or HOCl scavenger agent. Neither geranins A and D nor the extracts were able to scavenge H2O2 and (1)O2. In conclusion, G. niveum roots have proanthocyanidins with powerful radical scavenging in vitro activity. This property may partially explain the wide use of this plant in the Tarahumara indigenous system of medicine for the treatment of gastrointestinal illnesses (other than spasms), pain, and fevers associated with oxidative stress.  相似文献   

9.
The effects of different solvent systems (methanol, ethanol, acetone, and their 50% aqueous concentrations) and extraction procedures (microwave, ultrasound, Soxhlet and maceration) on the antioxidant activity of aerial parts of Potentilla atrosanguinea were investigated by three different bioassays: 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), 2,2'-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assays and ferric reducing antioxidant potential (FRAP). The 50% aqueous ethanol extracts exhibited strong antioxidant activity measured in terms of Trolox equivalent antioxidant capacity (TEAC) [(54.34 to 122.96, 29.82 to 101.22 and 13.64 to 41.43) mg of Trolox/g] with ABTS (*+), DPPH (*) and FRAP assays, respectively. In general, TEAC of Soxhlet extracts was found to be 1.8 and 3 times higher than ultrasound and maceration but slightly (1.2 times) higher than microwave. A positive correlation (r(2) = 0.931 to 0.982) was observed between total polyphenol (TPC) and total flavonoid (TFC) contents which ranged between 26.7 to 30.7 mg/g gallic acid equivalent and 16.8 to 20.8 mg/g quercetin equivalent respectively, with antioxidant activity. In addition, some of its bioactive phenolic constituents which contribute largely toward antioxidant potential such as chlorogenic acid, catechin, caffeic acid, p-coumaric acid and quercetin were also quantified in different extracts by RP-HPLC.  相似文献   

10.
The free radical scavenging activity of South African red (n = 46) and white (n = 40) cultivar wines was determined using 2,2'-azinobis(3-ethylbenzothialozinesulfonic acid) radical cations (ABTS(.+)) and 2,2-diphenyl-1-picrylhydrazyl radicals (DPPH.). The total antioxidant activities (TAA) of red and white wines using ABTS(.+) were 14.916 and 0.939 mM Trolox, respectively, at corresponding total phenol (TP) contents of 2339.0 and 273.8 mg of gallic acid equiv/L. Ruby Cabernet wines had the lowest TAA(ABTS) (13.177 mM Trolox) of the red wines, whereas the TAA(ABTS) values of Chardonnay and Chenin blanc wines were the highest (1.060 mM Trolox) and lowest (0.800 mM Trolox) of the white wines. The TAA(DPPH) values were of the same magnitude as the TAA(ABTS) values, and similar trends were observed. TAA correlated (P < 0.001) with total phenol content of red (r = 0.935) and white (r = 0.907) wines, as well as flavanol content of red wines (r = 0.866) and tartaric acid ester content of white wines (r = 0.767). Canonical discriminant analysis using phenolic composition and antioxidant activity was applied to differentiate between red and white cultivar wines.  相似文献   

11.
Two barley varieties, Gan4 and Hamelin, were malted to investigate the evolution of phenolic compounds and antioxidant activity during malting. The antioxidant activity was evaluated with DPPH radical scavenging activity, ABTS radical cation scavenging activity, reducing power, and metal chelating activity. Results showed that malting had significant influences on individual and total phenolic contents as well as antioxidant activities of two barley varieties. The contents of some phenolic compounds and the antioxidant activities decreased significantly during steeping and the early stages of germination and then increased remarkably during the later stages of germination and subsequent kilning. The most phenolic compounds identified in barley were (+)-catechin and ferulic acid, which both changed significantly during malting. Moreover, results from the Pearson correlation analysis showed that there were good correlations among DPPH radical scavenging activity, ABTS radical cation scavenging activity, reducing power, total phenolic content and sum of individual phenolic contents during malting.  相似文献   

12.
Four kinds of solvent extracts from three Chinese barley varieties (Ken-3, KA4B, and Gan-3) were used to examine the effects of extraction solvent mixtures on antioxidant activity evaluation and their extraction capacity and selectivity for free phenolic compounds in barley through free radical scavenging activity, reducing power and metal chelating activity, and individual and total phenolic contents. Results showed that extraction solvent mixtures had significant impacts on antioxidant activity estimation, as well as different extraction capacity and selectivity for free phenolic compounds in barley. The highest DPPH* and ABTS*+ scavenging activities and reducing power were found in 80% acetone extracts, whereas the strongest *OH scavenging activity, O2*- scavenging activity, and metal chelating activity were found in 80% ethanol, 80% methanol, and water extracts, respectively. Additionally, 80% acetone showed the highest extraction capacity for (+)-catechin and ferulic, caffeic, vanillic, and p-coumaric acids, 80% methanol for (-)-epicatechin and syringic acid, and water for protocatechuic and gallic acids. Furthermore, correlations analysis revealed that TPC, reducing power, DPPH* and ABTS*+ scavenging activities were well positively correlated with each other (p < 0.01). Thus, for routine screening of barley varieties with higher antioxidant activity, 80% acetone was recommended to extract free phenolic compounds from barley. DPPH* scavenging activity and ABTS*+ scavenging activity or reducing power could be used to assess barley antioxidant activity.  相似文献   

13.
Seven cane brown sugars (four from La Réunion, two from Mauritius, and one from France) were investigated for their polyphenol content and volatile composition in relation to their free radical scavenging capacity determined by ABTS and DPPH assays. The thin layer coated on the sugar crystal was extracted by Soxhlet extractor with dichloromethane. The volatile compounds of brown sugars were studied by GC-MS, and 43 compounds were identified. The total phenolic content of brown sugars was determined according to the Folin-Ciocalteu method. Phenolic compounds were quantified in the brown sugar extracts by LC-UV-ESI-MS. Brown sugar aqueous solutions exhibited weak free radical scavenging activity in the DPPH assay and higher antioxidant activity in the ABTS assay at relatively high concentration. The brown sugar extracts showed interesting free radical scavenging properties despite the low concentration of phenolic and volatile compounds. Sugar is a common foodstuff traditionally used for its sweetening properties, which might be accompanied by antioxidant properties arising from molecules (polyphenols, Maillard products) other than sucrose of the cane brown sugars.  相似文献   

14.
The outcome of different extraction procedures (microwave, ultrasound, Soxhlet, and maceration) on the antioxidant activity of seeds, leaves, pulp, and fruits of Hippophae rhamnoides (sea buckthorn or SBT) was investigated by two different bioassays: 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) and 2,2'-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assays. The SBT extracts were found to possess strong antioxidant activity measured in terms of TEAC (2.03-182.13 and 6.97-282.75 mg/g) with ABTS and DPPH assays, respectively. In general, the antioxidant capacity of microwave-assisted extracts was found to be significantly higher than those obtained by ultrasound-assisted extraction (UAE) and maceration while being slightly higher than Soxhlet extracts. Further, microwave extracts of seeds were found to possess maximum antioxidant capacity followed by leaves, fruits, and pulp. Also, the chemical composition of extracts, studied in terms of the total phenolic content, was found to be in the range of 1.9-23.5 mg/g Gallic acid equivalent (GAE), which indicates a strong correlation between antioxidant activity and phenolic content present in the SBT. In addition, some of its bioactive phenolic constituents, such as rutin ( 1), quercetin-3- O-galactoside ( 2), quercetin ( 3), myricetin ( 4), kaempferol ( 5), and isorhamnetin ( 6), were also quantified in different extracts by reverse-phase high-performance liquid chromatography (RP-HPLC).  相似文献   

15.
Radix Angelicae sinensis (named danggui in Chinese), a commonly used traditional Chinese medicine, has multiple pharmacological activities. The essential oil of danggui is usually considered to be its main active fraction. However, to date, studies on the antioxidant potentials of danggui have focused on water-soluble compounds. In this paper, the antioxidant activity of the commercial essential oil of danggui was investigated by DPPH radical scavenging assay, ABTS radical scavenging assay, and beta-carotene bleaching test. Antioxidant constituents in the essential oil were identified using HPLC coupled with DAD-MS and ABTS-based assay. The results showed that the essential oil of danggui has concentration-dependent antioxidant activity, which can be attributed to its component (coniferyl ferulate). This is the first report on the antioxidant activity of essential oil from danggui; its antioxidant potential was lower than those of positive controls, ascorbic acid and BHA.  相似文献   

16.
Conjugated linoleic acids (CLA) were investigated for free radical scavenging properties against the stable 2,2-diphenyl-1-picryhydrazyl radical (DPPH.) by electron spin resonance (ESR) spectrometry and spectrophotometric methods. ESR results demonstrated that CLA directly reacted and quenched free DPPH radicals in benzene, while spectrophotometric analysis showed the radical scavenging capacity of CLA in ethanol. Dose and time effects of CLA-DPPH. reactions were observed in both tests. The ED(50) of CLA was 18 mg/mL under experimental conditions. CLA are much weaker radical scavengers as compared to vitamin E, vitamin C, and BHT. Kinetics of CLA-DPPH. reactions was different to that of linoleic acid (LA)-DPPH. reactions. CLA reacted and quenched DPPH radicals at all tested levels without a lag phase, while LA had a lag phase and showed no radical quenching activity at levels of 5-80 mg/mL in 30 min. These data indicated that CLA can provide immediate protection against free radicals, but LA cannot.  相似文献   

17.
Tocochromanols are potent lipid-soluble antioxidants and essential nutrients for human health. Genetic engineering techniques were used to develop soybeans with enhanced vitamin E levels, including tocotrienols, which are not found in soybean. The gene encoding rice homogentisate geranylgeranyl transferase (HGGT) was overexpressed in soybeans using seed-specific and constitutive promoters. The association between abundance of vitamin E isomers and antioxidant activity was investigated during seed germination. With the exception of β-tocotrienol, all vitamin E isomers were detected in germinating seeds expressing OsHGGT. The antioxidant properties of germinating seed extracts were determined using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radicals and lipid peroxidation (TBARS). Compared with intact wild-type seeds, transgenic seeds showed increases in radical scavenging of 5.4-17 and 23.2-35.3% in the DPPH and ABTS assays, respectively. Furthermore, the lipid peroxidation levels were 2.0-4.5-fold lower in germinating seeds from transgenic lines than in wild-type seeds. Therefore, it appears that the antioxidant potential of transgenic oil-producing plants such as soybean, sunflower, and corn may be enhanced by overexpressing OsHGGT during seed germination.  相似文献   

18.
Free radical scavenging properties of wheat extracts   总被引：15，自引：0，他引：15  
Three hard winter wheat varieties (Akron, Trego, and Platte) were examined and compared for their free radical scavenging properties and total phenolic contents (TPC). Free radical scavenging properties of wheat grain extracts were evaluated by spectrophotometric and electron spin resonance (ESR) spectrometry methods against stable 2,2-diphenyl-1-picryhydrazyl radical (DPPH*) and radical cation ABTS*+ (2,2'-azino-di[3-ethylbenzthiazoline sulfonate]). The results showed that the three wheat extracts differed in their capacities to quench or inhibit DPPH* and ABTS*+. Akron showed the greatest activity to quench DPPH radicals, while Platte had the highest capacity against ABTS*+. The ED50 values of wheat extracts against DPPH radicals were 0.60 mg/mL for Akron, 7.1 mg/mL for Trego, and 0.95 mg/mL for Platte under the experimental conditions. The trolox equivalents against ABTS*+ were 1.31 +/- 0.44, 1.08 +/- 0.05, and 1.91 +/- 0.06 micromol/g of grain for Akron, Trego, and Platte wheat, respectively. ESR results confirmed that wheat extracts directly reacted with and quenched free radicals. The TPC were 487.9 +/- 927.8 microg gallic acid equivalents/g of grain. No correlation was observed between TPC and radical scavenging capacities for DPPH* and ABTS*+ (p = 0.15 and p > 0.5, respectively).  相似文献   

19.
In this study, the contents of total phenolics, flavonoids, anthocyanins, β-carotene, and lutein as well as free, conjugated, and insoluble bound phenolic acids were determined in whole kernels of 10 different colored maize genotypes. In addition, the antioxidant activity was evaluated as radical scavenging activity with ABTS (2,2-azino-bis/3-ethil-benothiazoline-6-sulfonic acid) and DPPH (2,2-diphenyl-1-picrylhydrazyl) reagents. Generally, considerable differences in phytochemical contents and antioxidant capacity were observed between the genotypes. The β-carotene and lutein contents ranged from 0 to 2.42 mg/kg d.m. and from 0 to 13.89 mg/kg d.m., respectively, whereas the total anthocyanin contents of anthocyanin-rich colored maize genotypes ranged from 2.50 to 696.07 mg CGE/kg d.m. (cyanidin 3-glucoside equivalent) with cyanidin 3-glucoside (Cy-3-Glu) as the most dominant form. The light blue ZPP-2 selfed maize genotype has a higher content of total phenolics, flavonoids, and ferulic acid as compared to other tested maize and the highest ABTS radical scavenging activity.  相似文献   

20.
Antioxidant capacities of vetiver (Vetiveria zizanioides) oil were evaluated by two different in vitro assays: the DPPH* free radical scavenging assay and the Fe2+-metal chelating assay. Results showed that the vetiver oil (VO) possessed a strong free radical scavenging activity when compared to standard antioxidants such as butylated hydroxytoluene (BHT) and alpha-tocopherol. However, its metal chelating capacity was relatively weak. VO (10 microL/mL) dissolved in methanol exhibited approximately 93% free radical scavenging activity in the DPPH* assay and approximately 34% Fe2+ chelating activity in the metal chelating assay. By contrast, 10 mM BHT and 0.1 mM alpha-tocopherol exhibited 93 and 89% free radical scavenging activities in the DPPH* assay, respectively, and 1 mM EDTA exhibited approximately 97% activity in the metal chelating assay. Among the complex constituents in the crude VO, beta-vetivenene, beta-vetivone, and alpha-vetivone, which had shown strong antioxidant activities, were isolated and identified using various chromatographic techniques including silica gel open column chromatography, silica HPLC, and GC-MS. These results show that VO and some of its inherent components can be potential alternative natural antioxidants.  相似文献   

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