Thiobarbituric Acid Reactive Substances Analysis Research Articles

Efficiency of Rosemary and Basil Essential Oils on the Shelf-Life Extension of Atlantic Mackerel (Scomber scombrus) Fillets Stored at 2°C.

The objective of the present study was to evaluate the impact of rosemary and basil essential oils (EOs) on the quality of Atlantic mackerel fillets stored at 2°C up to 15 days. Atlantic mackerel (Scomber scombrus) fillets were periodically evaluated to assess their textural, color, physicochemical, and spectral characteristics. The results indicated that rosemary and basil treatments were effective for inhibiting the formation of total volatile basic nitrogen (TVB-N) and lipid oxidation products during storage. Based on TVB-N values, the shelf life of Atlantic mackerel fillets treated with rosemary and basil EOs was extended by 2 and 5 days, respectively, compared to the control group. Similar results were obtained with thiobarbituric acid-reactive substance analysis, which demonstrated an extended shelf life of Atlantic mackerel immersed with rosemary and basil EOs of 2 and 3 days, respectively, compared to the control group. The factorial discriminant analysis applied on the concatenated first five principal components corresponding to the physicochemical, textural, color, and fluorescence measurements allowed clear discrimination of the three groups, because a correct classification rate of 93.3% was obtained. Therefore, treatment with basil and rosemary EOs, as natural biopreservative compounds, could present a high-potential application in the seafood industry.

The Effects of Novel Antimicrobials on Quality and Shelf-Life Characteristics of Blade Tenderized Beef Strip Loins

ObjectivesBeef tenderness is an important palatability attribute relating to consumer satisfaction. To enhance tenderness, and consumer satisfaction, blade tenderization (BT) is commonly employed; however, foodborne outbreaks have been associated with BT products. Application of antimicrobial interventions prior to BT is commonly employed by the meat industry to reduce the inherent risk of BT. As new antimicrobial technologies arise, they must also be tested to ensure quality and shelf life is not compromised. The objectives of this study were to investigate the effects of pulse ultra-violet light (PUV), 5% levulinic acid + 0.5% sodium dodecyl sulfate (LVA+SDS), and electrolyzed oxidizing water (EOW; 50 ppm Cl), on beef strip loin (SL) subprimals prior to BT, and assess their effects on shelf life and sensory characteristics compared to SL treated with 4.5% lactic acid (LA), and no antimicrobial intervention (CON).Materials and MethodsWhole USDA Choice beef SL (n = 75) of known date were assigned randomly to antimicrobial interventions across 3 replicates. Pulse UV samples were treated for 15 s at 5.754 J/cm2 6 ± 2 cm from the quartz window. All other treatments were applied to subprimals using a 6-nozzle sanitizing cabinet (0.42 L/nozzle·min–1 at 275.79 kPa). After treatment, all SL made a single pass, lean side up, through a mechanical tenderizer (Ross TC700MC). After BT, SL were vacuum packaged, boxed, and stored (0 ± 1°C) for 7 d. Following storage, subprimals were squared and 2 steaks (2.54 cm) were cut from the anterior face with 1 designated for Warner-Bratzler shear force and the other for trained sensory analysis. Pulse UV samples were not included in sensory analysis due to the PUV equipment being previously utilized in pathogen studies. After steak removal, roasts (5 cm) were cut for shelf life analysis, packaged in Styrofoam trays with PVC overwrap and randomly assigned to 0, 1, 2, 3, 5, or 7 d of display in open top coffin display cases (0 ± 1.5°C, 2 defrost cycle every 24 h) and 24 h lighting (1600- 2100 lux; 30000K). On each day objective color was measured on d 7 roasts for L*, a*, b*, hue, chroma, and ∆E. Aerobic plate count (APC) and thiobarbituric acid reactive substance analysis (TBARS) were also quantified on d 0, 1, 2, 3, 5, and 7 roasts. Data were analyzed using Proc Mixed (V9.4, SAS Inst. Inc., Cary, NC) as a randomized split-plot where subprimal was the whole plot and steak or roast was the subplot. The PDIFF option of least squares means was utilized to test for differences (ɑ ≤ 0.05).ResultsAntimicrobial treatment prior to BT did not (P > 0.05) affect objective color measures. However, as display progressed L*, a*, b*, and chroma decreased (P < 0.05), while hue and ∆E values increased (P < 0.05). As expected, APC increased (P < 0.05) with extended display, and, even though APC were similar (P > 0.05) among CON (5.64 log CFU/cm2), PUV (5.20 log CFU/cm2), and EOW (5.78 log CFU/cm2), both LVA+SDS- and LA-treated roast had lower (P < 0.05) APC than all other treatments (3.49 and 4.33 log CFU/cm2, respectively). However, antimicrobial treatments did not (P > 0.05) affect lipid oxidation, WBSF, or sensory characteristics.ConclusionThe results from this study suggest that LVA+SDS could be used as an antimicrobial prior to SL BT without compromising quality or sensory characteristics.

Effects of Feeding Peroxidized Soybean Oil to Finishing Barrows on the Shelf-Life of Bacon and Loin Chops

ObjectivesPeroxidized lipids are, at times, used in finishing pig diets and have been shown to induce oxidative stress and reduce growth performance. The effects of feeding peroxidized lipids on the shelf-life of pork products is not as clear, as previous research has reported contradictory results. Therefore, the objective of this study was to test the effect of feeding soybean oil (SO) subjected to varying degrees of thermal abuse to finishing pigs on lipid oxidation and sensory attributes of commercially manufactured bacon during 90 d of simulated food-service-style storage; and the color stability and lipid oxidation of pork loin chops during 11 d of simulated retail display.Materials and MethodsFifty-five individually housed barrows were randomly allotted to 1 of 4 diets containing 10% SO: 1.) not heated (CON), or heated at 2.) 45°C for 288 h (45C/288h), 3.) 90°C for 72 h (90C/72h), or 4.) 180°C for 6 h (180C/6h), and fed for 81 d. Barrows were slaughtered on d 82 at the University of Illinois. At 24 h postmortem, bellies (NAMP 408) and Canadian back loins (NAMP 414) were removed from carcasses. Two 2.54 cm thick chops were cut from the Canadian back loin and used to determining color stability and thiobarbituric acid reactive substances (TBARS) during simulated retail display. Bellies were skinned (NAMP 409) then processed into sliced bacon at a commercial facility. Bacon was stored at –40°C without an atmosphere barrier to simulate food service storage conditions. Samples were removed on d 0, 30, 60, and 90 for sensory evaluation by 6 trained panelists and analysis of TBARS. Loins were packaged 1 d postmortem in foam trays covered in oxygen permeable overwrap and subjected to an 11 d simulated retail display at 4°C with full exposure to fluorescent light. Loins were evaluated for CIE L*, a*, and b*, reflectance ratio, and visual discoloration daily. Loin samples were analyzed for TBARS on d 1 and d 10 of display. Data were analyzed as a complete randomized design repeated in time with fixed effects of oil treatment and storage day. Storage location (shelf) served as a random effect for analysis of loin shelf-life. Bacon sensory data were analyzed as a partially balanced incomplete block design repeated in time, with fixed effects of oil treatment and storage time, and sensory session serving as a random effect.ResultsThere was no effect of oil treatment on TBARS (P > 0.90), oxidized odor (P = 0.63), or oxidized flavor (P = 0.79) of bacon. As expected lipid oxidation, oxidized odor, and oxidized flavor increased (P < 0.0001) over the 90 d storage period. There was no effect (P > 0.51) of oil treatment on L*, hue angle, or TBARS of loin chops subjected to a 10 d simulated retail display. However, chops from pigs fed 45C/288h oil were more red (greater a*; P < 0.01) and more yellow (greater b*; P < 0.01) than the other 3 treatments. Chroma and reflectance were also greater (P < 0.03) greater for these same chops; however, the 45C/288h chops were the most (P < 0.01) discolored after 10 d of simulated retail display.ConclusionFeeding peroxidized soybean oil did not affect lipid oxidation in either food-service packaged bacon or fresh loin chops. However, feeding the 45C/288h oil (mild thermal abuse) resulted in chops that were more red had more intense color, but also were the most discolored at the conclusion of an 11 d simulated retail display.

Effects of power ultrasound on oxidation and structure of beef proteins during curing processing

The aim of this study was to evaluate the effects of power ultrasound intensity (PUS, 2.39, 6.23, 11.32 and 20.96Wcm−2) and treatment time (30, 60, 90 and 120min) on the oxidation and structure of beef proteins during the brining procedure with 6% NaCl concentration. The investigation was conducted with an ultrasonic generator with the frequency of 20kHz and fresh beef at 48h after slaughter. Analysis of TBARS (Thiobarbituric acid reactive substances) contents showed that PUS treatment significantly increased the extent of lipid oxidation compared to static brining (P<0.05). As indicators of protein oxidation, the carbonyl contents were significantly affected by PUS (P<0.05). SDS–PAGE analysis showed that PUS treatment increased protein aggregation through disulfide cross-linking, indicated by the decreasing content of total sulfhydryl groups which would contribute to protein oxidation. In addition, changes in protein structure after PUS treatment are suggested by the increases in free sulfhydryl residues and protein surface hydrophobicity. Fourier transformed infrared spectroscopy (FTIR) provided further information about the changes in protein secondary structures with increases in β-sheet and decreases in α-helix contents after PUS processing. These results indicate that PUS leads to changes in structures and oxidation of beef proteins caused by mechanical effects of cavitation and the resultant generation of free radicals.

Antioxidant activity of phenolic compounds added to a functional emulsion containing omega-3 fatty acids and plant sterol esters

The effect of eleven compounds extracted from red propolis on the oxidative stability of a functional emulsion was evaluated. Emulsions prepared with Echium oil as omega 3 (ω-3 FA) source, containing 1.63g/100mL of α-linolenic acid (ALA), 0.73g/100mL of stearidonic acid (SDA) and 0.65g/100mL of plant sterol esters (PSE) were prepared without or with phenolic compounds (vanillic acid, caffeic acid, trans-cinnamic acid, 2,4-dihydroxycinnamic acid, p-coumaric acid, quercetin, trans-ferulic acid, trans,trans-farnesol, rutin, gallic acid or sinapic acid). tert-Butylhydroquinone and a mixture containing ascorbic acid and FeSO4 were applied as negative and positive controls of the oxidation. Hydroperoxide, thiobarbituric acid reactive substances (TBARS), malondialdehyde and phytosterol oxidation products (POPs) were evaluated as oxidative markers. Based on hydroperoxide and TBARS analysis, sinapic acid and rutin (200ppm) showed the same antioxidant activity than TBHQ, representing a potential alternative as natural antioxidant to be applied in a functional emulsion containing ω-3 FA and PSE.

Effects of ergot alkaloid consumption on horses completing a standardized trail ride

s / Journal of Equine Veterinary Science 33 (2013) 321-399 323 treatment and then again at days 30, 60, 90 during the supplementation period. Reflective three dimensional markers (3.81cmindiameter)wereplacedatall jointson fore and hind limbs during video recording. Video footage was captured using two high speed Ethernet GigE uEyeTM cameras (IDS Imaging Development Systems, Obersulm, Germany) placed perpendicular to the line of travel on either side of the horse. Video footage was recorded into the EquineTecTM (Monroe, GA, USA) software program for analysis. Blood via jugular puncture was taken the morning following video recording. Hematocrit values were analyzed immediately. Whole blood and plasma was frozen for later analysis. Thiobarbituric acid reactive substances (TBARS) analysis was conducted onplasma according to procedures established by C. JoandD.U.Ahn [3].DatawasanalyzedusingSASversion9.3 ProcGLMwithrepeatedmeasuresover time todetermine the effects of treatment, time, and treatment by time interactions. P valuesof P<0.05were consideredsignificant.After90 days, glucosamine horses showed greater front leg retraction distance (P1⁄4.01) as compared to earlier time points. No significant difference in this parameter was seen in control horses. Additionally, a trend toward greater front fetlock flexionwasobserved inglucosamine supplementedhorses as compared to controls. No differences between control and treatment were observed in TBARS analysis. In conclusion, oral supplementation of glucosamine sulfate resulted in modest changes in biomechanical parameters measured. Differences in blood oxidative levels between treatments were not observed.

Effect of ergot alkaloid consumption on recovery of horses completing a standardized performance exercise test under hot, humid conditions

s / Journal of Equine Veterinary Science 33 (2013) 321-399 323 treatment and then again at days 30, 60, 90 during the supplementation period. Reflective three dimensional markers (3.81cmindiameter)wereplacedatall jointson fore and hind limbs during video recording. Video footage was captured using two high speed Ethernet GigE uEyeTM cameras (IDS Imaging Development Systems, Obersulm, Germany) placed perpendicular to the line of travel on either side of the horse. Video footage was recorded into the EquineTecTM (Monroe, GA, USA) software program for analysis. Blood via jugular puncture was taken the morning following video recording. Hematocrit values were analyzed immediately. Whole blood and plasma was frozen for later analysis. Thiobarbituric acid reactive substances (TBARS) analysis was conducted onplasma according to procedures established by C. JoandD.U.Ahn [3].DatawasanalyzedusingSASversion9.3 ProcGLMwithrepeatedmeasuresover time todetermine the effects of treatment, time, and treatment by time interactions. P valuesof P<0.05were consideredsignificant.After90 days, glucosamine horses showed greater front leg retraction distance (P1⁄4.01) as compared to earlier time points. No significant difference in this parameter was seen in control horses. Additionally, a trend toward greater front fetlock flexionwasobserved inglucosamine supplementedhorses as compared to controls. No differences between control and treatment were observed in TBARS analysis. In conclusion, oral supplementation of glucosamine sulfate resulted in modest changes in biomechanical parameters measured. Differences in blood oxidative levels between treatments were not observed.

The impact of postharvest interventions on the color stability and, subsequently, the palatability of beef from cattle fed wet distillers grain1

Two hundred forty heifers were fed at Oklahoma State University in Stillwater, OK, in 1 of 2 treatment groups: a dry rolled corn (CON) diet or a diet including 30% wet distillers grains plus solubles (WDGS). Chuck rolls (n = 60) and paired strip loins (n = 75 pairs; 38 CON and 37 WDGS) were collected from each treatment group and processed at 3 d and 14 d, respectively. After grinding, each chuck was separated into 8 polyvinyl chloride (PVC) film overwrapped packages and 8 high oxygen modified atmosphere packaging (MAP), each containing approximately 0.23 kg of ground beef, for evaluation by a trained color panel, a trained color panel and a trained sensory panel and for thiobarbituric acid reactive substance (TBARS) analysis. After 14 d, 1 strip loin from each pair was injected with an enhancement solution. Steaks from each strip loin were fabricated and packaged, one-half in PVC and one-half in MAP. In addition to the evaluation by trained color and sensory panels and TBARS analysis, steaks were subjected to instrumental color evaluation using a HunterLab Miniscan XE and Warner-Bratzler Shear Force analysis using an Instron Universal Testing Machine. Ground beef exhibited no significant differences in color between dietary treatments; however, sensory panelists did find MAP WDGS had less beefy flavor (P = 0.05) and more painty flavor (P = 0.01) intensities than the MAP CON ground beef. Cattle fed WDGS discolored more (P = 0.01) and had less bright steaks than cattle fed the CON when MAP and enhanced. Distillers fed, nonenhanced (nonE) MAP steaks were redder and yellower than control steaks (P < 0.05) on removal from simulated retail display. There were no other significant (P > 0.05) color differences between dietary treatments using any other combination of postharvest interventions. Sensory panel results indicated WDGS NE PVC products were juicier and more tender (P < 0.05), initially, and contained less connective tissue (5.3 ± 0.1, 5.5 ± 0.1, and 5.9 ± 0.4, respectively) than the steaks from CON carcasses (5.1 ± 0.1, 5.4 ± 0.1, and 5.8 ± 0.4, respectively). Although WDGS NE MAP steaks showed more oxidation than CON NE MAP steaks on removal from retail case, all TBAR values were well below a threshold of 1 mg malonaldehyde/kg. Essentially, MAP but not enhancing products from cattle fed WDGS may be the best way to maintain a visually appealing appearance in the retail case but at possible risk to product juiciness.

Effects of postharvest processes on quality of Australian sardines (Sardinops sagax) and redbait (Emmelichthys nitidus nitidus) for feeding aquacultured southern bluefin tuna (Thunnus maccoyii)

Feed nutritional quality impacts on the performance of aquacultured species. This study was undertaken to assess the consequences of existing postharvest handling practices on nutritional quality of local baitfish (Australian sardines, Sardinops sagax and redbait, Emmelichthys nitidus nitidus) used to feed farmed southern bluefin tuna (Thunnus maccoyii). Controlled experiments were then undertaken to determine the most appropriate postharvest treatments to maintain baitfish nutritional quality, assessed through measurement of vitamins C and E, histamine, K value and TBARS. During frozen storage (−18 °C) vitamins and fish freshness decreased significantly and rancidity increased; after approximately 3 months baitfish were of questionable utility, particularly as a source of antioxidants. On-land freezing method [i.e. block or individually quick frozen (IQF)] affected vitamin E loss with IQF sardines losing vitamin E faster than block-frozen baitfish. Block-frozen baitfish, particularly sardines, should be thawed in seawater, not air or freshwater, to minimize vitamin losses. Thawing time should be no more than 2 days, and baitfish storage less than 3 months. Thiobarbituric acid reactive substances (TBARS) correlated well with remaining vitamin E, indicating its usefulness as an indicator of antioxidant status. TBARS analysis is methodologically simpler, faster and cheaper than that for vitamins, and is therefore recommended for determination of baitfish nutritional quality.

Synthesis, Characterization, and Bioavailability in Rats of Ferric Phosphate Nanoparticles

Particle size is a determinant of iron (Fe) absorption from poorly soluble Fe compounds. Decreasing the particle size of metallic Fe and ferric pyrophosphate added to foods increases Fe absorption. The aim of this study was to develop and characterize nanoparticles of FePO4 and determine their bioavailability and potential toxicity in rats. Amorphous FePO4 nanopowders with spherical structure were synthesized by flame spray pyrolysis (FSP). The nanopowders were characterized and compared with commercially available FePO4 and FeSO4, including measurements of specific surface area (SSA), structure by transmission electron microscopy, in vitro solubility at pH 1 and 2, and relative bioavailability value (RBV) to FeSO4 in rats using the hemoglobin repletion method. In the latter, the potential toxicity after Fe repletion was assessed by histological examination and measurement of thiobarbituric acid reactive substances (TBARS). The commercial FePO4 and the 2 FePO4 produced by FSP (mean particle sizes, 30.5 and 10.7 nm) had the following characteristics: SSA: 32.6, 68.6, 194.7 m2/g; in vitro solubility after 30 min at pH 1: 73, 79, and 85% of FeSO4; and RBV: 61, 70, and 96%, respectively. In the histological examinations and TBARS analysis, there were no indications of toxicity. In conclusion, nanoparticles of FePO4 have a solubility and RBV not significantly different from FeSO4. Reducing poorly soluble Fe compounds to nanoscale may increase their value for human nutrition.

Effect of gamma radiation on refrigerated mechanically deboned chicken meat quality

Samples of mechanically deboned chicken meat (MDCM) were irradiated in the frozen form with doses of 0.0, 3.0 and 4.0 kGy, stored at 2±1 °C and evaluated for their sensory characteristics, color, thiobarbituric acid reactive substances (TBARS) and total psychrotrophic bacterial count for up to 12 days. The sensory analysis showed that volatile compounds associated with the odor irradiation produces, were dissipated from the samples of irradiated MDCM during storage and that the oxidation odor perceived in the samples irradiated with doses of 3.0 and 4.0 kGy was more pronounced ( P<0.05) than in the non-irradiated samples, as from the 8th and 12th day of refrigeration, respectively, in agreement with the TBARS values. Irradiated MDCM showed higher values ( P<0.05) for a ∗ (redness) than the non-irradiated samples as from the 4th day under refrigeration. Considering the sensory analyses, color, psychrotrophic bacterial counts and TBARS analyses as a whole, the MDCM samples irradiated with doses of 0.0, 3.0 and 4.0 kGy were acceptable under refrigerated storage for 4, 10 and 6 days, respectively.

Lipid Peroxidation and Urinary Excretion of Vitamin E in Rats Submitted to an Immunological Inflammatory Process

Inflammation is a protective physiologic response, generally controlled by the organism at the injury site. Vitamin E is the most important antioxidant in the lipid phase present in nature and acts by interrupting the chain reaction produced by free radicals. The objective of this study was to evaluate the effect of inflammation on vitamin E levels and lipid peroxidation in rats. Forty Wistar rats (four groups of 10 rats each) were studied over a period of 15 days. Two substances inducing the inflammatory process were parenterally administered, anti-rat basement membrane serum (ABMG) and Freund's complete adjuvant (FAG). Lipid peroxidation levels in hepatic and renal tissue and in plasma and urine were analyzed and compared with the control (CG). Vitamin E was determined by HPLC and lipid peroxidation by quantification of thiobarbituric acid reactive substances (TBARS). ABMG produced more (p<0.05) TBARS in renal and hepatic tissues (0.7 ± 0.11 and 1.28 ± 0.27 nmol/g protein, respectively) compared to CG (0.65 ± 0.81 and 0.69 ± 0.13 nmol/g protein). Analysis of TBARS in urine did not show statistically significant differences between the experimental groups and the control. Vitamin E levels in the hepatic tissue of ABMG and FAG (40.7 ± 10.04 and 44.26 ± 20.24 µg/g tissue) were higher than in CG (22.37 ± 8.20 µg/g tissue) while in kidney tissue and plasma these values were lower (P<0.05). Renal excretion was increased (P<0.05) in the group that received anti-rat basement membrane serum (22.39 ± 0.11 mmol/mL) compared to CG (0.56 ± 0.056 mmol/mL). We conclude that the acute inflammatory process causes important alterations in the metabolism of vitamin E and lipid peroxidation leading to a significantly increased excretion of this vitamin in the urine.

Serum alpha-tocopherol and selenium in Belgian infants and children.

Previous studies showed low selenium (Se) concentrations in Belgian children. Serum alpha-tocopherol, retinol, total cholesterol, high-density lipoprotein and low-density lipoprotein cholesterol, selenium (Se), and thiobarbituric acid-reactive substances were examined. In order to obtain further information on the Se status in Belgian children, Se, alpha-tocopherol, retinol, and lipid concentrations were examined and signs of peroxidative lipid damage were evaluated in a subgroup. The study was performed in 524 children (0-14 yr old) during vaccination campaigns. Three age groups were analyzed: 0-1, 1-4, and 4-14 yr. In 87 of them, where sufficient amounts of serum were available, analysis of thiobarbituric acid-reactive substances was done. Infants have high serum alpha-tocopherol concentrations: (23.2 micromol/L [median and interquartile range: 18.6-30.2]) and low Se concentrations (0.37 mol/L [0.27-0.47]). Se concentrations rise significantly during the first 4 yr (p < 0.0001) (Mann-Whitney U-test, tied p-values): 0.70 micromol/L (0.59-0.82); in the 4-14 yr olds, it was 0.75 micromol/L (0.67-0.86). These values remain low compared to results coming from other parts of the world. Alpha-tocopherol concentrations decrease significantly after infancy (p < 0.0001). The ratio alpha-tocopherol/total cholesterol is higher in infants. This is induced by the high vitamin E content of infant formulas. Signs of serum lipid peroxidation could not be detected by analysis of serum malondialdehyde concentrations. High alpha-tocopherol concentrations, as those observed in infant serum lipids, could be one of the protective mechanisms from the peroxidative lipid damages, sometimes observed in a low-Se status.

5-Aminolevulinic acid induced lipid peroxidation after light exposure on human colon carcinoma cells and effects of α-tocopherol treatment

This work relates to studies on modes of phototoxicity by protoporphyrin (PpIX) after incubation of 5-aminolevulinic acid (5-ALA) on cultured cells. Lipid peroxidation in the 5-ALA incubated primary adenocarcinoma cells from the rectosigmoid colon (WiDr cells) was determined by measurement of protein-associated thiobarbituric acid reactive substances (TBARS). TBARS were increased 2-fold in cells treated with 2 mM 5-ALA for 3.5 h in serum enriched medium. After illumination of 5-ALA incubated cells, TBARS were formed in a light dose dependent manner. TBARS analysis were compared with high-performance liquid chromatography (HPLC) analysis of malondialdehyde, and results indicate that 90% of the thiobarbituric reactive substances were due to malondialdehyde. Pretreating WiDr cells with α-tocopherol for 48 h inhibits the cytotoxic effect of 5-ALA and increases 5-fold the light dose needed to kill 50% of the cells. Pretreatment with α-tocopherol shows a considerable decrease (about 80%) on TBARS formation after illumination. The cellular content of α-tocopherol was determined by HPLC and found to be 15.3 pmol/10 6 cells.

Antioxidant effects of herbs in Crete

Low morbidity and mortality rates of coronary heart disease (CHD) have been found in Crete. 1 Lionis C Koutis A Antonakis N Isacsson A Lindholm L Fioretos M Mortality rates in a cardiovascular ‘low risk’ population in rural Crete. Fam Pract. 1993; 10: 300-304 Crossref PubMed Scopus (5) Google Scholar Some of the reasons proposed are low serum cholesterol, high physical activity, and a diet low in saturated fat and high in monosaturated fat. Herbs may also have a preventive effect. We studied the antioxidant effect on extracts of ten herbs collected in Crete. Origanum dictamnus (wild and cultivated dittany), Matricaria recutita (chamomile), Satureja thymbra (savory), Coridothymus capitatus (thyme), Mentha pulegium (penny royal), Salvia pomifera (wild sage), Salvia fruticosa (Greek sage), Origanum majorana (marjoram), Mentha spicata (spearmint) were collected between May and June, 1996, from the area of Mixorruma when then were flowering. All are native to Crete apart from Origanum majorana which was collected from a pot kept by a villager. The plants were air dried. About 1 g of each herb was extracted in 100 mL of water at 100°C by shaking for 5 min. Extracts were filtered and freeze dried. The ability of extracts to inhibit lipid peroxidation was assayed in human bronchiole cells (A 549 from ATCC, Rockville, MD, USA). 2 Leanderson P Olsen-Faresjö Å Tagesson C Green tea polyphenols inhibit oxidant-induced DNA strand breakage in cultured lung cells. Free Rad Biol Med. 1997; 23: 235-242 Crossref PubMed Scopus (86) Google Scholar Cells were seeded into 24-well plates, 200 000/well in 500 μL in Dulbecco's modification of Eagle's medium supplemented with 10% fetal calf serum and penicillin 50 IU/mL, streptomycin 50 IU/mL, and 2 mmol/L L-glutamine (Flow Laboratories, Irvine, UK) and allowed to attach overnight in 5% CO2 at 37°C. Cells were pretreated for 2 h with herb extract (50 μL of a 10 mg/mL stock solution in 1 mL culture medium, made fresh daily), or 10 μmol/L alpha-ditocopherol at 37°C. After treatment the cells were washed with PBS and exposed to 10 μmol/L iron (III) chloride for 30 min at 37°C, or a low-dose of ozone for 1 min in a plastic container exposed to ozone from an ozoniser (Coralife model 100). Lipid peroxidation was determined by analysis of thiobarbituric-acid reactive substances. 200 μL 20% (w/v) trichloroacetic acid and 400 μL thiobarbituric acid (Merck, Darmstadt, Germany) was added to each well, the plate was covered and incubated at 95°C for 40 min and then chilled before determination of the absorbance at 543 nm. A standard curve of malondialdehyde was made from 1,1,3,3-tetraethoxypropane (Sigma Chemical Co, St Louis, MO, USA).

Diaphragmatic function after resistive breathing in vitamin E-deficient rats.

The effects of vitamin E deficiency on diaphragm function were studied at rest and after resistive breathing (RB) in Sprague-Dawley rats (wt 300-400 g). The animals were pair fed a vitamin E-deficient diet (E-def) or a matched vitamin E-sufficient diet (E-suf). Each diet group was then further subdivided into a group that breathed unimpeded (control) and a second group that breathed through an inspiratory resistor until the animals were unable to sustain 70% of their maximum airway pressure. Diaphragm samples were obtained for analysis of thiobarbituric acid-reactive substances, glutathione (GSH) concentrations, and glutathione disulfide (GSSG) concentrations. In vitro isometric contractile studies were also performed and included twitch (Pt) and maximum tetanic (Po) tensions, force-frequency curves, fatigue index, and recovery index. Pt was significantly reduced in the E-suf RB group as well as both of the E-def groups. Po was also significantly reduced in both E-def groups. The E-def rats subjected to RB showed a significant decrease in tension at both high and low frequencies compared with the E-suf rats. Concentrations of diaphragm thiobarbituric acid-reactive substances were significantly increased in both E-def groups. RB in both E-suf and E-def rats resulted in increases in diaphragm concentrations of GSSG and decreases in the GSH/GSSG ratios. We conclude that reduction of contractile function, lipid peroxidation, and activation of the GSH redox cycle occur with RB and that these effects are significantly increased in the presence of vitamin E deficiency.

Resistive breathing activates the glutathione redox cycle and impairs performance of rat diaphragm

Free radical activation and lipid peroxidation have been described in skeletal muscle during strenuous exercise. We hypothesized that oxygen radicals could also be formed in the diaphragm muscle during strenuous resistive breathing and that these radicals might affect diaphragm function. Seven control and 12 experimental male Sprague-Dawley rats were studied. Six experimental animals were subjected to resistive breathing (RB) alone and six animals received 15 min of mechanical ventilatory support (MV) after the resistive breathing period. Inspiratory resistance was adjusted to maintain airway opening pressure at 70% maximum in both groups until exhaustion. Diaphragm samples were obtained for analysis of thiobarbituric acid-reactive substances (TBAR), reduced glutathione (GSH), and glutathione disulfide (GSSG). In vitro isometric contraction times, twitch (Pt) tension and maximum tetanic (Po) tension, force-frequency curves, fatigue index, and recovery index were measured. In RB and MV compared with controls, there were significant decreases in Pt and Po. Diaphragm TBAR concentrations were increased in MV compared with controls or RB. GSSG-to-total glutathione ratio was increased in RB and MV compared with controls. Production of free radicals during RB and MV may represent an important mechanism of diaphragmatic injury that could contribute to the decline in contractility.

Lipid hydroperoxy and hydroxy derivatives in copper-catalyzed oxidation of low density lipoprotein.

Oxidation of low density lipoprotein (LDL) causes changes in the biological properties of LDL that may be important in atherogenesis. That LDL oxidation is accompanied by lipid peroxidation has been demonstrated, but previous analyses of the products of LDL oxidation have not included measurement of specific lipid hydroperoxy and hydroxy derivatives. In this study, LDL was isolated from plasma of normal volunteers and exposed to oxygenated buffer and 5 microM CuSO4 for 24 h. Oxidized LDL showed decreased linoleate (18:2) and arachidonate (20:4) content with increased concentrations of thiobarbituric acid reactive substances (TBARS) and hydroxy and hydroperoxy 18:2 and 20:4. The electrophoretic mobility of the LDL protein also was increased by oxidation. After reduction, the hydroxy fatty acids were characterized by gas chromatography-mass spectrometric analysis of the trimethylsilyl ether methyl ester derivatives. The hydroperoxy and hydroxy derivatives accounted for approximately 70% of the linoleate consumed during LDL oxidation and represented 45-fold more product than was measured by TBARS analysis. Numerous biological properties, including cytotoxic and chemoattractant activities of hydroperoxy and hydroxy fatty acids, have been reported, but the manner in which they may contribute to atherogenesis requires further study.