Free Radical Scavenging Activity of 4-(3,4-Dihydroxybenzoyloxymethyl)phenyl-O-β-d-glucopyranoside from Origanum vulgare and Its Protection against Oxidative Damage

4-(3,4-Dihydroxybenzoyloxymethyl)phenyl-O-β-d-glucopyranoside (DBPG), a polyphenolic glycoside, isolated from Origanum vulgare has shown 1,1-diphenyl-2-picrylhydrazyl (DPPH(?))-scavenging capacity in previous work. This study demonstrated that DBPG exhibits antioxidant activity by a series of DPPH(?), 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS(?+)), and superoxide anion radical (O(2)(?-)) radical-scavenging assays. The inhibition of lipid peroxidation (LP) by DBPG exceeded that by l-ascorbic acid (AA) in a liposome model system. Adding DBPG to mouse liver and brain tissue inhibited the formation of thiobarbituric acid reactive substances (TBARS) to a greater extent than did trolox. In the oxygen stress test, BNLCL2 and HaCaT cells pretreated with DBPG showed increased activities of glutathione peroxidase (GPx), perhaps as a result of reduction of the production of reactive oxygen species (ROS). These findings proved that DBPG had antioxidant activities and a cytoprotective effect in hepatocytes and keratinocytes, suggesting that DBPG may be a useful food and cosmetic additive.     

Antioxidant activity and inhibition of lipid peroxidation in germinating seeds of transgenic soybean expressing OsHGGT

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.     

Total antioxidant capacity of arginine-conjugated linoleic acid (CLA) complex

Conjugated linoleic acids (CLA) have shown diverse biological activities, including anti-carcinogenic, anti-atherosclerotic, anti-adipogenic, and anti-diabetogenic effects. Recent reports also showed that CLA has free radical scavenging capacity, which may give health benefits to human beings. However, the application of CLA as a bioactive ingredient has been limited due to its insolubility in water. To overcome this problem, we investigated antioxidant activities of arginine (Arg)-CLA, a water-soluble CLA salt, using both 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2,2'-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assays. CLA, Arg, and Arg-CLA all exerted radical scavenging activities in a dose-dependent manner in both assays. Arg-CLA at 20 mM scavenged 89 and 55% of ABTS and DPPH radicals in 3 h, respectively, whereas CLA alone quenched only 48 and 26% of them under the same conditions. The antioxidant activity of the Arg-CLA complex was found to be synergistic in ABTS assay and comparable to that of vitamin E in DPPH assay.     

Inhibitory activities of soluble and bound millet seed phenolics on free radicals and reactive oxygen species

Oxidative stress, caused by reactive oxygen species (ROS), is responsible for modulating several pathological conditions and aging. Soluble and bound phenolic extracts of commonly consumed millets, namely, kodo, finger (Ravi), finger (local), foxtail, proso, little, and pearl, were investigated for their phenolic content and inhibition of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and ROS, namely, hydroxyl radical, peroxyl radical, hydrogen peroxide (H(2)O(2)), hypochlorous acid (HOCl), and singlet oxygen ((1)O(2)). Inhibition of DPPH and hydroxyl radicals was detrmined using electron paramagnetic resonance (EPR) spectroscopy. The peroxyl radical inhibitory activity was measured using the oxygen radical absorbance capacity (ORAC) assay. The scavenging of H(2)O(2), HOCl, and (1)O(2) was evaluated using colorimetric methods. The results were expressed as micromoles of ferulic acid equivalents (FAE) per gram of grain on a dry weight basis. In addition, major hydroxycinnamic acids were identified and quantified using high-performance liquid chromatography (HPLC) and HPLC-mass spectrometry (MS). All millet varieties displayed effective radical and ROS inhibition activities, which generally positively correlated with phenolic contents, except for hydroxyl radical. HPLC analysis revealed the presence of ferulic and p-coumaric acids as major hydroxycinnamic acids in phenolic extract and responsible for the observed effects. Bound extracts of millet contributed 38-99% to ROS scavenging, depending on the variety and the test system employed. Hence, bound phenolics must be included in the evaluation of the antioxidant activity of millets and other cereals.     

Free radicals scavenging efficiency of a few naturally occurring flavonoids: a comparative study

The interaction of antiperoxidative flavonoids artocarpin (AR), cycloartocarpin (CAR), dalspinin (DP), dalspinosin (DPO), and dalspinin-7-O-galactoside (DPG) with 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS(.+)) and O2(-.) was studied in phosphate buffer (pH 7.4). The ability of these compounds to inhibit lipid peroxidation and DNA scission was also investigated. The radical scavenging efficiency of flavonoids is demonstrated by the reduction of nitrogen-centered radical cation (ABTS(.+)). The reduction of ABTS(.+) follows the order quercetin > morin > Trolox > AR > DPO > CAR > DP. Inhibition of lipid peroxidation was studied by following Mb(IV) reduction, induced by lipid, arachidonic acid. These results are compared with those obtained for well-known antioxidants such as quercetin, morin, and Trolox. The structure-activity relationships between chemical structures of the flavonoids and their radical scavenging activities are anlayzed. The scavenging of O2(-.), inhibition of lipid peroxidation, and DNA damage depend on the oxidation potential of the flavonoids. The possible mechanism for radical scavenging activities of flavonoids in relation to their structure is also outlined.     

Evaluation of antioxidant and prooxidant activities of bamboo Phyllostachys nigra var. Henonis leaf extract in vitro

Solvent-extracted bamboo leaf extract (BLE) containing chlorogenic acid, caffeic acid, and luteolin 7-glucoside was evaluated in vitro for free radical scavenging and antioxidant activities using a battery of test methods. BLE exhibited a concentration-dependent scavenging activity of DPPH radical. BLE prolonged the lag phase and suppressed the rate of propagation of liposome peroxidation initiated by peroxyl radical induced by 2,2'-azobis(2-amidinopropane dihydrochloride (AAPH) at 37 degrees C. BLE also prevented human low-density lipoprotein oxidation, mediated by Cu(2+), which was monitored by the lower formation of conjugated diene and fluorescence and a reduced negative charge of apo-B protein. Finally, BLE protected supercoiled DNA strand against scission induced by AAPH-mediated peroxyl radical. Prooxidant activity of BLE was seen in a Cu(2+)-induced peroxidation of structured phosphatidylcholine liposome, indicating catalytic peroxidation due to a relatively high reducing power of BLE. It was concluded that the BLE has both antioxidant activity and prooxidant activity; the antioxidant activity was attributed to free radical scavenging activity, and the prooxidant activity, albeit minor, resulted from the reducing power of plant phenolics in the presence of transitional metal ions.     

Isolation and characterization of antioxidant protein fractions from melinjo (Gnetum gnemon) seeds

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.     

In vitro antioxidant and antiproliferative activities of selenium-containing phycocyanin from selenium-enriched Spirulina platensis

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.     

Effects of extraction solvent mixtures on antioxidant activity evaluation and their extraction capacity and selectivity for free phenolic compounds in barley (Hordeum vulgare L.)

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.     

Comparison of spectrophotometric and electrochemical methods for the evaluation of the antioxidant capacity of buckwheat products after hydrothermal treatment

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.     

Antioxidant functions of selected allium thiosulfinates and S-alk(en)yl-L-cysteine sulfoxides

Pure thiosulfinates, R-S(O)S-R (2), where R = Me (2a), Pr (2b), or All (2c), at levels up to 4 mM were not capable of scavenging hydrogen peroxide or superoxide anion. Relative to standard antioxidants (ascorbic acid, n-propyl gallate, butylated hydroxytoluene, Trolox, and reduced glutathione), these thiosulfinates were 1-3 orders of magnitude less efficient at reducing 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, 0.5-2 orders of magnitude less efficient at quenching singlet oxygen, and about equally effective at scavenging hydroxyl radical. Generally, AllS(O)SAll (2c) was the most effective and PrS(O)SPr (2b) was the least effective thiosulfinate in these assays, except that MeS(O)SMe (2a) exhibited no quenching effect toward singlet oxygen. These thiosulfinates were also incapable at levels up to 0.1 mM (where they were toxic) of in vitro induction of quinone reductase (QR) in murine hepatoma (hepa 1c1c7) cells. However, S-1-propenyl-L-cysteine sulfoxide (isoalliin, 1a) and cycloalliin (3) induced QR in this system at 2 mM and 1 mM, respectively, although doubling of QR required levels of 10-15 mM.     

Reducing, radical scavenging, and chelation properties of in vitro digests of alcalase-treated zein hydrolysate

The objective of the study was to assess the antioxidant potential of alcalase-treated zein hydrolysate (ZH) during a two-stage (1 h of pepsin --> 0.5-2 h of pancreatin, 37 degrees C) in vitro digestion. Sephadex gel filtration and high-performance size exclusion chromatography were used to separate ZH into fractions. The amino acid composition, 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS(+*)) and 1,1-diphenyl-2-picrylhydrazyl (DPPH*) free radical scavenging activity, reducing power, and Cu (2+) chelation ability were tested to determine the antioxidant efficacy of ZH. Results showed that in vitro digests of ZH contained up to 16.5% free amino acids, with short peptides (<500 Da) making up the rest of the mass. The ABTS(+*) scavenging activity of ZH was decreased by 27% (P<0.05) after pepsin treatment but was fully recovered upon subsequent pancreatin digestion, while the DPPH* scavenging activity of ZH was substantially less than ABTS(+*) scavenging activity and showed a 7-fold reduction following pancreatin treatment. The reducing power of ZH increased 2-fold (P<0.05) following pancreatin digestion when compared with nondigested ZH. The ability of ZH to sequester Cu (2+) was reduced by pepsin digestion but was reestablished following pancreatin treatment. The antioxidant activity demonstrated by in vitro digests of ZH (1-8 mg/mL) was comparable to or exceeded (P<0.05) that of 0.1 mg/mL of ascorbic acid or BHA. The results suggested that dietary zein alcalase hydrolysate may have the benefit to promote the health of the human digestive tract.     

Antioxidant activities of extracts from Barkleyanthus salicifolius (Asteraceae) and Penstemon gentianoides (Scrophulariaceae)

Various extracts of the aerial parts of Barkleyanthus salicifolius (Asteraceae) and Penstemon gentianoides (Scrophulariaceae) have been used in folk medicine to treat many ailments, particularly inflammation and migraine. Neither the bioactive components responsible nor the mechanisms involved have been evaluated. Here are reported antioxidant activities of their methanol, dichloromethane, and ethyl acetate extracts. Samples were evaluated for oxygen radical absorption capacity (ORAC), ferric reducing antioxidant power (FRAP), 2,2-diphenyl-1-picryl-hydrazyl (DPPH) radical scavenging, and inhibition of the formation of thiobarbituric acid reactive species (TBARS), a measure of lipid peroxidation. Antioxidant activities were strongly correlated with total polyphenol content. The most active extracts from P. gentianoides in scavenging DPPH radicals and inhibiting TBARS formation were the methanol extract (A) and a further ethyl acetate extract of this (E). Partition E was further divided into eight fractions, and both E and the fractions were compared for activity against butylated hydroxytoluene, quercetin, and tocopherol. Partition E and the most active fractions, 5 and 6, were found to have I(50) values of 14.1, 38.6, and 41.8 ppm, respectively, against DPPH and 18.5, 26.0, and 12.7 ppm, respectively, against TBARS formation. Consistent with this finding, partition E and fractions 4-6 had the greatest ORAC and FRAP values. These results show that these plants could be useful antioxidant sources.     

Studies on the antioxidant activity of Echinacea root extract

Methanol extracts of freeze-dried Echinacea (E. angustifolia, E. pallida, and E. purpurea) roots were examined for free radical scavenging capacities and antioxidant activities. Root extracts of E. angustifolia, E. pallida, and E. purpurea were capable of scavenging hydroxyl radical. Similar scavenging activities for each variety were found for both 1,1-diphenyl-2-picrylhydrazyl radical and ABTS radical. Meanwhile, antioxidant activities of all three varieties of Echinacea were found to delay the formation of conjugated diene hydroperoxide induced by the thermal decomposition of 2, 2'-azobis(2-amidinopropane) dihydrochloride and extend the lag phase of peroxidation of soybean liposomes. Echinacea root extracts suppressed the oxidation of human low-density lipoprotein, as evaluated by reduced agarose electrophoretic mobility following oxidative modification by Cu(2+). The mechanisms of antioxidant activity of extracts derived from Echinacea roots included free radical scavenging and transition metal chelating.     

Evolution of phenolic compounds and antioxidant activity during malting

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.     

Characterization of the volatile composition of essential oils of some lamiaceae spices and the antimicrobial and antioxidant activities of the entire oils

The essential oils of Ocimum basilicum L., Origanum vulgare L., and Thymus vulgaris L. were analyzed by means of gas chromatography-mass spectrometry and assayed for their antioxidant and antimicrobial activities. The antioxidant activity was evaluated as a free radical scavenging capacity (RSC), together with effects on lipid peroxidation (LP). RSC was assessed measuring the scavenging activity of the essential oils on 2,2-diphenyl-1-picrylhydrazil (DPPH(*)) and OH(*) radicals. Effects on LP were evaluated following the activities of essential oils in Fe(2+)/ascorbate and Fe(2+)/H(2)O(2) systems of induction. Essential oils exhibited very strong RSCs, reducing the DPPH radical formation (IC(50)) in the range from 0.17 (oregano) to 0.39 microg/mL (basil). The essential oil of T. vulgaris exhibited the highest OH radical scavenging activity, although none of the examined essential oils reached 50% of neutralization (IC(50)). All of the tested essential oils strongly inhibited LP, induced either by Fe(2+)/ascorbate or by Fe(2+)/H(2)O(2). The antimicrobial activity was tested against 13 bacterial strains and six fungi. The most effective antibacterial activity was expressed by the essential oil of oregano, even on multiresistant strains of Pseudomonas aeruginosa and Escherichia coli. A significant rate of antifungal activity of all of the examined essential oils was also exhibited.     

Antioxidant activity of A-type proanthocyanidins from Geranium niveum (Geraniaceae)

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.     

Comparative study on antioxidant activity of lycopene (Z)-isomers in different assays

Several studies have implicated the potent antioxidant properties of lycopene. However, most of the studies used only the (all-E)-isomer. (Z)-Isomers of lycopene were found in substantial amounts in processed foods and in human tissues. In the present study, we investigated in vitro the antioxidant activity of (5Z)-, (9Z)-, and (13Z)-lycopene compared to the (all-E)-isomer. Additionally, prolycopene, the (7Z,9Z,7'Z,9'Z)-isomer found in tangerine tomatoes, was analyzed. No significant differences were found between the isomers in ferric reducing antioxidant power assay and in bleaching the radical cation of 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), both based on ET mechanisms. In contrast, scavenging activity against peroxyl radicals generated by thermal degradation of 2,2'-azobis(2-amidinopropane) (AAPH) was higher in the (Z)-isomers. (5Z)-Lycopene was most antioxidant in scavenging lipid peroxyl radicals, evaluated by analyzing the inhibition of MbFe(III) lipid peroxidation of linoleic acid in mildly acidic conditions (pH 5.8) in a micellar environment, modeling a possible antioxidant action in the gastric compartment.     

Comparison of the radical scavenging potential of polar and lipidic fractions of olive oil and other vegetable oils under normal conditions and after thermal treatment

The antioxidant activity (IC(50)) of extra virgin olive oil (EVOO), commercial olive oil, and other vegetable oils (soybean, sunflower, and corn oil) was determined by UV-vis and by electron paramagnetic resonance (EPR) spectroscopy of the stable radical 2,2-diphenyl-1-picrylhydrazyl (DPPH). Also, we studied the antioxidant activity of the methanol soluble phase (methanolic, MF) and the nonsoluble phase (lipidic, LF) of oils by the same methods. Similarly, we studied the effect of heating on the antioxidant activity at 160 and 190 degrees C. Also, the MF, containing the polyphenolic substances, was used for measurements of the radical scavenging capacity toward the most important oxygen free radicals, superoxide anion (O(2)(*)(-)) and hydroxyl (HO(*)) radicals. Results showed that soybean oil and EVOO had the highest antioxidant potential and thermal stability. In the case of soybean oil, the antioxidant capacity is the result of its high content of gamma- and delta-tocopherols (with the highest antioxidant capacity and thermostabilities), whereas in EVOO, the antioxidant potential is the result of the combination of specific antioxidant polyphenols, which are acting additionally as effective stabilizers of alpha-tocopherol. The high content of EVOO in tyrosol, hydrotyrosol, and oleuropein and other polyphenolics with radical scavenging abilities toward superoxide anion and hydroxyl radical suggests that olive oil possesses biological properties that could partially account for the observed beneficial health effects of the Mediterranean diet.     

Antimicrobial and antioxidant properties of rosemary and sage (Rosmarinus officinalis L. and Salvia officinalis L., Lamiaceae) essential oils

The essential oils of rosemary ( Rosmarinus officinalis L.) and sage ( Salvia officinalis L.) were analyzed by means of gas chromatography-mass spectrometry and assayed for their antimicrobial and antioxidant activities. Antimicrobial activity was tested against 13 bacterial strains and 6 fungi, including Candida albicans and 5 dermatomycetes. The most important antibacterial activity of both essential oils was expressed on Escherichia coli, Salmonella typhi, S. enteritidis, and Shigella sonei. A significant rate of antifungal activity, especially of essential oil of rosemary, was also exhibited. Antioxidant activity was evaluated as a free radical scavenging capacity (RSC), together with the effect on lipid peroxidation (LP). RSC was assessed by measuring the scavenging activity of essential oils on 2,2-diphenyl-1-picrylhydrazil (DPPH) and hydroxyl radicals. Effects on LP were evaluated following the activities of essential oils in Fe(2+)/ascorbate and Fe(2+)/H2O2 systems of induction. Investigated essential oils reduced the DPPH radical formation (IC50 = 3.82 microg/mL for rosemary and 1.78 microg/mL for sage) in a dose-dependent manner. Strong inhibition of LP in both systems of induction was especially observed for the essential oil of rosemary.