Effect of halide salts on development of surface browning on fresh-cut 'Granny Smith' (Malus × domestica Borkh) apple slices during storage at low temperature.

BACKGROUND: The postharvest life of fresh-cut apple slices is limited by browning on cut surfaces. Dipping in halide salt solutions was examined for their inhibition of surface browning on 'Granny Smith' apple slices and the effects on biochemical factors associated with browning. RESULTS: Delay in browning by salts was greatest with chloride = phosphate > sulfate > nitrate with no difference between sodium, potassium and calcium ions. The effectiveness of sodium halides on browning was fluoride > chloride = bromide > iodide = control. Polyphenol oxidase (PPO) activity of tissue extracted from chloride- and fluoride-treated slices was not different to control but when added into the assay solution, NaF > NaCl both showed lower PPO activity at pH 3-5 compared to control buffer. The level of polyphenols in treated slices was NaF > NaCl > control. Addition of chlorogenic acid to slices enhanced browning but NaCl and NaF counteracted this effect. There was no effect of either halide salt on respiration, ethylene production, ion leakage, and antioxidant activity. CONCLUSION: Dipping apple slices in NaCl is a low cost treatment with few impediments to commercial use and could be a replacement for other anti-browning additives. The mode of action of NaCl and NaF is through decreasing PPO activity resulting in reduced oxidation of polyphenols.

Substitution effects of a carbonated hydroxyapatite biomaterial against intoxication chloride nickel-exposed rats.

AIMS: This study aimed to investigate the potential effects of a synthetic apatite (carbonated hydroxyapatite) on the detoxification of a group of male "Wistar" rats exposed to nickel chloride. METHODS: Toxicity was evaluated by rats' bioassay of nickel chloride. Wistar rats received this metal daily by gavage for seven days (4 mg/ml nickel chloride/200 g body weight, BW). To detoxify this organism, a subcutaneous implantation of the apatite is made. RESULTS: The results revealed that exposure to nickel induced oxidative stress, disorders in the balances of ferric phosphocalcic, renal failures, liver toxicity and significant increase in nickel rates in the bones of intoxicated rats. The application of the carbonated hydroxyapatite presented in this study restored those disorders back to normal. The synthetic apatite protected the rats against the toxic effects of nickel by lowering the levels of lipid peroxidation markers and improving the activities of defense enzymes. It also amended ferric and phosphocalcic equilibriums, protected liver and kidney functions and reduced the nickel rate in the bones of the rats. Overall, the results provided strong support for the protective role of carbonated hydroxyapatite in the detoxification of rats exposed to nickel. Those beneficial effects were further confirmed by physico-chemical characterization (X-ray diffraction and infrared spectroscopy), which revealed its property of anionic and cationic substitution, thus supporting its promising candidacy for future biomedical application. CONCLUSION: The hydroxyapatite is an effective biomaterial to solve health problems, particularly detoxification against metals (nickel).

Atorvastatin active metabolite inhibits oxidative modification of small dense low-density lipoprotein.

We tested the hypothesis that atorvastatin active metabolite (ATM), on the basis of its distinct structural features and potent antioxidant activity, preferentially inhibits lipid oxidation in human small dense low-density lipoprotein (sdLDL) and other small lipid vesicles. LDL, sdLDL, and various subfractions were isolated from human plasma by sequential ultracentrifugation, treated with ATM, atorvastatin, pravastatin, rosuvastatin, or simvastatin and were subjected to copper-induced oxidation. Lipid oxidation was measured spectrophotometrically as a function of thiobarbituric acid reactive substances formation. Similar analyses were performed in reconstituted lipid vesicles enriched in polyunsaturated fatty acids and prepared at various sizes. ATM was found to inhibit sdLDL oxidation in a dose-dependent manner. The antioxidant effects of ATM in sdLDL were 1.5 and 4.7 times greater (P < 0.001) than those observed in large buoyant LDL and very low-density lipoprotein subfractions, respectively. ATM had similar dose- and size-dependent effects in reconstituted lipid vesicles. None of these effects were reproduced by atorvastatin (parent) or any of the other statins examined in this study. These data suggest that ATM interacts with sdLDL in a specific manner that also confers preferential resistance to oxidative stress. Such interactions may reduce sdLDL atherogenicity and improve clinical outcomes in patients with cardiovascular disease.

Formulation of liposomes loading lentisk oil to ameliorate topical delivery, attenuate oxidative stress damage and improve cell migration in scratch assay.

Pistacia lentiscus L. is a sclerophyllous shrub capable of growing under harsh climatic conditions especially in the Mediterranean Basin. Different products can be obtained from this plant, such as essential oil, mastic gum or even fixed oil. The last is well known for its flavor which is mainly exploited in the food industry. Additionally, it has been traditionally used in the treatment of skin diseases, but, at the moment, any suitable formulation for skin delivery has been formulated and its biological effects was not deeply confirmed. Given that, in the present study, the lentisk oil has been formulated in liposomes at different concentrations (10, 20, 30 mg/ml) and their physicochemical, technological and main biological properties have been evaluated. Vesicles were prepared by using natural soy lecithin and a green and organic solvent free method, thus obtaining spherical, small (~ 118 nm), homogeneously dispersed (0.27) and highly negatively charged (~ -62 mV) vesicles. The used amount of oil loaded in liposomes (10, 20, 30 mg/ml) modulated the penetration ability of vesicles in the skin, favoring the deposition of the payload in the deeper strata. The loading in the vesicles potentiated the ability of oil to counteract the damaging effects caused by hydrogen peroxide in keratinocytes and fibroblasts and facilitate their migration in a cell monolayer lesion. Overall findings suggested that the incorporation of lentisk oil in liposomes made from soy lecithin can be an alternative and natural approach to exploit it in pharmaceutical ad cosmetical applications and manufacturing natural products suitable for the treatment of skin lesions.

Evaluating clinical and laboratory effects of ozone in non-surgical periodontal treatment: a randomized controlled trial.

OBJECTIVE: This study aims to evaluate the clinical and biochemical (oxidative stress and pro-inflammatory mediators) effects of the gaseous ozone use accompanied by scaling and root planning (SRP) in periodontal treatment. MATERIAL AND METHODS: The study population consisted of 40 patients with chronic periodontitis (CP) randomly sorted into two groups of 20. The experimental group received SRP plus 3 watts gaseous ozone in two separate applications five days apart, whereas the control group received SRP plus placebo. Clinical periodontal parameters were assayed and saliva samples were taken before the initial and one month after the second treatment. Periodontal examination assessed plaque index (PI), gingival index (GI), probing depth, and clinical attachment level (CAL). Total antioxidant status (TAS), total oxidant status (TOS), nitric oxide (NO), 8-hydroxy-2'-deoxyguanosine (8-OHdG), myeloperoxidase (MPO), glutathione (GSH), malondialdehyde (MDA), and transforming growth factor-beta (TGF-ß) levels were evaluated from saliva samples. RESULTS: Changes following treatment in PI, GI, probing depth, and CAL scores were similar for both groups (p>0.05). Of note, TGF-ß levels were observed to be higher in the treatment group than in controls (p<0.05). Changes in 8-OHdG, TAS, TOS, NO, MPO, GSH and MDA levels, however, were not significantly different between groups (p>0.05). CONCLUSION: The findings of this study indicate that SRP plus gaseous ozone versus SRP alone does not correlate to a significant improvement in periodontal recovery.

Thymosin beta4 is cytoprotective in human gingival fibroblasts.

Thymosin beta4 (Tbeta(4)) is a naturally occurring, ubiquitous, non-toxic protein with documented wound-healing, anti-inflammatory, anti-apoptotic, and tissue-repair properties in skin, the ocular surface, and the heart. The ability of Tbeta(4) to demonstrate similar protective properties in cells of the oral cavity was analyzed using an in vitro model of cultured human gingival fibroblasts. Thymosin beta 4 significantly suppressed the secretion of interleukin-8 (IL-8) following stimulation with tumor necrosis factoralpha (TNF-alpha), suggesting that it may suppress the inflammatory response initiated by pro-inflammatory cytokines. By contrast, Tbeta(4) was not effective in protecting fibroblasts from challenge with lipopolysaccharide purified from Porphyromonas gingivalis or Escherichia coli. Thymosin beta 4 was able to protect gingival fibroblasts against the known cytotoxic effects of chlorhexidine digluconate, a mouthrinse containing chlorhexidine digluconate, and carbamide peroxide. Additionally, Tbeta(4) was able to protect gingival fibroblasts from the apoptosis that is induced by stimulation with TNF-alpha or by exposure to chlorhexidine. Because of its multifunctional roles in protecting cells against damage, Tbeta(4) may have significant potential for use as an oral heathcare aid with combined antimicrobial, anti-inflammatory, anti-apoptotic, and cytoprotective properties.

Synergistic effects of zeaxanthin and its binding protein in the prevention of lipid membrane oxidation.

There is growing evidence that high levels of the macular xanthophyll carotenoids lutein and zeaxanthin may be protective against visual loss due to age-related macular degeneration, but the actual mechanisms of their protective effects are still poorly understood. We have recently purified, identified and characterized a pi isoform of glutathione S-transferase (GSTP1) as a zeaxanthin-binding protein in the macula of the human eye which specifically and saturably binds to the two forms of zeaxanthin endogenously found in the foveal region. In this report, we studied the synergistic antioxidant role of zeaxanthin and GSTP1 in egg yolk phosphatidylcholine (EYPC) liposomes using hydrophilic 2,2'-azobis(2-methyl-propionamidine) dihydrochloride (AAPH) and lipophilic 2,2'-azobis(2,4-dimethylvaleronitrile) (AMVN) as lipid peroxyl radical generators. The two zeaxanthin diastereomers displayed synergistic antioxidant effects against both azo lipid peroxyl radical generators when bound to GSTP1. In the presence of GSTP1, nondietary (3R,3'S-meso)-zeaxanthin was observed to be a better antioxidant than dietary (3R,3'R)-zeaxanthin. This effect was found to be independent of the presence of glutathione. Carotenoid degradation profiles indicated that the zeaxanthin diastereomers in association with GSTP1 were more resistant to degradation which may account for the synergistic antioxidant effects.

The interaction of flavonoids with membranes: potential determinant of flavonoid antioxidant effects.

Twenty six phenolic substances including representatives of the families, flavanones, flavanols and procyanidins, flavonols, isoflavones, phenolic acids and phenylpropanones were investigated for their effects on lipid oxidation, membrane fluidity and membrane integrity. The incubation of synthetic phosphatidylcholine (PC) liposomes in the presence of these phenolics caused the following effects: (a) flavanols, their related procyanidins and flavonols were the most active preventing 2,2'-azo-bis (2,4-dimethylvaleronitrile) (AMVN)-induced 2-thiobarituric acid-reactive substances (TBARS) formation, inducing lipid ordering at the water-lipid interface, and preventing Triton X-100-induced membrane disruption; (b) all the studied compounds inhibited lipid oxidation induced by the water-soluble oxidant 2,2'-azo-bis (2-amidinopropane) (AAPH), and no family-related effects were observed. The protective effects of the studied phenolics on membranes were mainly associated to the hydrophilicity of the compounds, the degree of flavanol oligomerization, and the number of hydroxyl groups in the molecule. The present results support the hypothesis that the chemical structure of phenolics conditions their interactions with membranes. The interactions of flavonoids with the polar head groups of phospholipids, at the lipid-water interface of membranes, should be considered among the factors that contribute to their antioxidant effects.

Action of methanolic extract of mung bean hulls as inhibitors of lipid peroxidation and non-lipid oxidative damage.

The antioxidant effects of methanolic extract of mung bean hulls (MEMBH) on lipids and non-lipids, including liposome, carbohydrate, protein and 2'-deoxyguanosine (2'-dG), were investigated. MEMBH exhibited a remarkable antioxidant effect in a liposome model system, indicating that the extract was an inhibitor of lipid peroxidation. The inhibitory effect of MEMBH on deoxyribose damage was amount-dependent and it afforded considerable protection against damage to deoxyribose. In addition, MEMBH at low amounts was more effective in protecting protein oxidation. Furthermore, the oxidation of 2'-dG to 8-hydroxy-2'-deoxyguanosine (8-OH-2'dG) was inhibited by MEMBH. These results show that the extract also was an inhibitor of non-lipid oxidation damage. The extract exhibited metal binding ability and scavenging activity for hydrogen peroxide and hydroxyl radical, which may explain the mechanism of their protecting lipids and non-lipids from oxidative damage.

Evaluating clinical and laboratory effects of ozone in non-surgical periodontal treatment: a randomized controlled trial

Abstract Objective: This study aims to evaluate the clinical and biochemical (oxidative stress and pro-inflammatory mediators) effects of the gaseous ozone use accompanied by scaling and root planning (SRP) in periodontal treatment. Material and Methods: The study population consisted of 40 patients with chronic periodontitis (CP) randomly sorted into two groups of 20. The experimental group received SRP plus 3 watts gaseous ozone in two separate applications five days apart, whereas the control group received SRP plus placebo. Clinical periodontal parameters were assayed and saliva samples were taken before the initial and one month after the second treatment. Periodontal examination assessed plaque index (PI), gingival index (GI), probing depth, and clinical attachment level (CAL). Total antioxidant status (TAS), total oxidant status (TOS), nitric oxide (NO), 8-hydroxy-2'-deoxyguanosine (8-OHdG), myeloperoxidase (MPO), glutathione (GSH), malondialdehyde (MDA), and transforming growth factor-beta (TGF-β) levels were evaluated from saliva samples. Results: Changes following treatment in PI, GI, probing depth, and CAL scores were similar for both groups (p>0.05). Of note, TGF-β levels were observed to be higher in the treatment group than in controls (p<0.05). Changes in 8-OHdG, TAS, TOS, NO, MPO, GSH and MDA levels, however, were not significantly different between groups (p>0.05). Conclusion: The findings of this study indicate that SRP plus gaseous ozone versus SRP alone does not correlate to a significant improvement in periodontal recovery.

The effect of alpha-tocopherol on the nitration of gamma-tocopherol by peroxynitrite.

It has been proposed (S. Christen et al. Proc. Natl. Acad. Sci. USA 94, 3217-3222, 1997) that although alpha-tocopherol (alpha-TH) is an efficient antioxidant, the presence of gamma-tocopherol (gamma-TH) may be required to scavenge peroxynitrite-derived reactive nitrogen species. To investigate the reactions between alpha-TH, gamma-TH, and peroxynitrite, endogenous levels of both alpha-TH and gamma-TH were monitored when low-density lipoprotein was oxidized in the presence of the peroxynitrite generator 5-amino-3-(4-morpholinyl)-1, 2,3-oxadiazolium (SIN-1). SIN-1 oxidized alpha-TH while gamma-TH levels remained constant. The sparing of gamma-TH was also demonstrated when 1,2-dilauroyl-sn-glycero-3-phosphocholine liposomes containing alpha-TH and gamma-TH were incubated with either SIN-1 or peroxynitrite. Our data show that alpha-TH inhibits peroxynitrite-mediated gamma-TH nitration, i.e., 5-NO2-gamma-tocopherol formation. The rate constants for the reactions between both alpha-TH and gamma-TH with peroxynitrite suggest that the sparing of gamma-TH by alpha-TH does not occur by competitive scavenging, but may be due to the formation of a transient gamma-TH intermediate. Nitration of gamma-TH becomes significant only after alpha-TH levels have been depleted. We conclude alpha-TH alone is sufficient to remove any peroxynitrite-derived reactive nitrogen species, as the presence of alpha-TH attenuates nitration of both gamma-TH and tyrosine. The present results also indicate that a bolus addition of peroxynitrite or SIN-1 to liposomes containing gamma-TH forms 5-NO2-gamma-tocopherol in similar yields. This is in contrast to their reaction profile with tyrosine in aqueous solution. Under these conditions, SIN-1 does not form nitrotyrosine at detectable yields.

Influence of oligomer chain length on the antioxidant activity of procyanidins.

The antioxidant activity of catechin monomers and procyanidin (dimers to hexamers) fractions purified from cocoa was studied in two in vitro systems: liposomes and human LDL. Liposome oxidation (evaluated as formation of 2-thiobarbituric acid reactive substances) was initiated with 2,2'-azobis (2-amidinopropane) hydrochloride (AAPH), 2,2'-azobis (2,4-dimethylvaleronitrile) (AMVN), iron/ascorbate, or UV-C; LDL oxidation (evaluated as formation of conjugated dienes) was initiated with Cu(2+) or AAPH. Catechin monomers and procyanidin fractions inhibited both liposome and LDL oxidation. Monomers, dimers, and trimers fractions were the most effective antioxidants when liposome oxidation was initiated in the aqueous phase. When oxidation was initiated in the lipid domains, higher molecular weight procyanidins were the most effective. All fractions significantly inhibited Cu-mediated LDL oxidation; no significant effect of procyanidin molecular weight was observed. The hexamer fraction was the least effective with respect to preventing AAPH initiated LDL oxidation. Results reported herein give further evidence on the influence of the oligomer chain length on the antioxidant protection by procyanidins.