Tooth bleaching agents contain powerful oxidizing agents, which serve as the main part of bleaching agents because of its release of effective bleaching component. It has been a hot topic whether tooth bleaching agents exert negative influence on oral health. In order to provide train of thoughts and reference for further clinical researches and treatments, this review paper focuses on bleaching agents' effects on the growth of oral microbes and the formation of biofilms.
Bacteria ; drug effects ; growth & development ; Biofilms ; drug effects ; growth & development ; Humans ; Hydrogen Peroxide ; Mouth ; microbiology ; Oral Health ; Oxidants ; pharmacology ; Tooth Bleaching ; Tooth Bleaching Agents ; pharmacology

BACKGROUND: Coenzyme Q10 is an endogenous lipid soluble antioxidant that scavenges reactive oxygen species (ROS) directly, inhibits biomolecule oxidation, and affects antioxidant defense in vivo. Kinetin (N6-furfuryladenine) belongs to the family of N6-substituted adenine derivatives known as cytokinins. Kinetin also exerts anti-aging effects. Commercial products of coenzyme Q10 and kinetin are developed and are selling as a rejuvenating drug. However, the action mechanisms of kinetin are not fully known, though it has been suggested to act both as an inhibitor of reactive oxygen species (ROS) formation and as a scavenger of ROS. Thioctic acid (alpha-Lipoic acid), which becomes a powerful antioxidant in its reduced form, has been suggested as a dietary supplement to treat diseases associated with excessive oxidant stress. Exposure of the skin to ultraviolet (UV) radiation, particulary UVB (290-320nm), causes adverse biological effects, including alterations in cutaneous immune cells, photoaging and photocarcinogenesis. Several studies have shown that coenzyme Q10, kinetin, and thioctic acid afforded the protection effects against UVB-induced inflammatory responses and photoaging. Objective and Method: In this study, we investigated the effects of coenzyme Q10, kinetin and thioctic acid on UVB irradiated human skin fibroblasts using a viability test, thiobarbituric acid assay and Northern blot analysis. RESULT: Cell survival curves after UVB irradiation showed a dose dependent decremental pattern by trypan blue exclusion assay. Only 30% of dermal fibroblasts survived at 150mJ/cm2 UVB irradiation. The damage was associated with cell membrane lipid peroxidation, as shown by accumulation malondialdehyde (MDA). By pre-cultivation with coenzyme Q10, kinetin and thioctic acid, a significant protection effect was noted as an increase in the absolute number of surviving cells and marked decrease in the levels of MDA. CONCLUSION: Coenzyme Q10, kinetin, and thioctic acid, which have been newly accepted as having UV protection properties, are effective membrane peroxidation inhibitors and inhibitors of reactive oxygen species (ROS) formation and scavenger of ROS.
Humans ; Oxidants

It has been being some studies on biomedical effects of mulberry leaves in the world. Mulberry trees are widly cultivated in VietNam to take leaves for fed of silkworm. However, there were few studies on extraction, determination and antioxidation of mulberry leaves in VietNam. Objectives: extraction and determination of polyphenol from mulberry leaves. Evaluation of antioxidant capacities of mulberry leaf extract powders. Methods: Mulberry leaf extract powder were extracted from mulberry leaves by five solvens: methanol 100%, methanol 75%, n-hexan 100%, ethylacetat 100%. Polyphenol concentration of the extracts are determined by ferrous sulphate and follin reagent assay. Antioxidant capacities of the powders are based on peroxidation of linoleic acid at 40oC. Results: Among five solvens, the extract by methanol 75% from 50g dried leaves is best. The powder is 1.94g with 2.62% of polyphenol. Polyphenol concentraion of the extract powders are determined by two methods: ferrous sulphate and follin reagent. The result with ferrous sulphate method is more accurate than follin reagent method. The mulberry leave extract powders inhibited linoleic acid peroxidation at the 1h and 12h of reaction (only 15.5% to 42.2% linoleic acid peroxidated) in comparison with control (100% linoleic acid peroxidated). Conclusions: Polyphenol from mulberry leaves was extracted by some solvens. Among them extraction of polyphenol by methanol 75% is best. Polyphenol concentration of extract powders can be dedermined by ferrous sulphat. The extract powders from mulberry leaves exhibited antioxidant capacities in vitro. The extract powder by methanol 75% showed highest antioxidant capacitiy.
Oxidants ; Morus

PURPOSE: The modification of radiation-induced apoptosis by EGCG, known as antioxidants or oxidants, was studied in mice spleens irradiated with a lethal dose. MATERIALS AND METHODS: Male C57BL/6 mice were divided into control, irradiation-only, and EGCG (100 mg/kg i.p. 1 h before irradiation) pretreatment groups. The mice were irradiated with a single whole-body dose of 7 Gy. The apoptosis in the spleens after irradiation of the lethal dose were analyzed by TUNEL assay. In addition, the expression levels of the Bax and Bcl-2 proteins were quantified using a Western blotting method. RESULTS: The induction of apoptosis was detected in the splenic white pulp. The highest level of apoptosis was detected at 8 hours after irradiation. No significant difference was identified by the apoptotic index (53.9% vs. 52.1%, p=0.328) and relative Bax protein expression (0.86 vs. 0.81, p=0.335), between the irradiation-only and EGCG pretreatment group, respectively. However, a lower Bax/Bcl-2 ratio (1.64 vs. 0.97, p=0.037) and higher relative expression level of Bcl-2 protein (0.57 vs. 0.82, p=0.037) was measured in the EGCG pretreatment group. CONCLUSION: The EGCG pretreatment neither decreased the radiation-induced apoptosis in mice splenocytes, nor induced additional apoptosis.
Male ; Humans ; Oxidants

OBJECTIVES: To examine the tooth whitening effects of a 3% hydrogen peroxide gel.METHODS: Twenty participants were given experimental tooth whitening gels containing 3% hydrogen peroxide, and another 20 participants, who served as the control group, were given tooth whitening gels that contained no hydrogen peroxide. Both groups used their respective whitening agents for 1 week, and tooth lightness was examined at baseline and 4 and 7 days after the experiment.RESULTS: Compared with the control group, in the experimental group, lightness values, determined using VITA classical A1-D4® and VITA SYSTEM 3D-MASTER®, were significantly increased after using the 3% hydrogen peroxide whitening agent (P < 0.01) both 5 and 7 days post-application (P < 0.05).CONCLUSIONS: The study findings confirmed that an improved tooth whitening effect could be expected with the use of a new type of whitening gel containing 3% hydrogen peroxide.
Bleaching Agents ; Gels ; Hydrogen Peroxide ; Hydrogen ; Tooth Bleaching ; Tooth ; Toothpastes

The diabetic patients are usually suffered from oxidation stress. Green tea is one of the good herbal medicines has been used for treatment of some diseases. Objectives: Evaluate change of antioxidant status in blood and effect of the green tea polyphenol on this change in the experimental diabetic rats. Methods: Using in vivo model to investigate some biological indicators in STZ - induced diabetic rats fed with high fat diet and to evaluate effect of the green tea polyphenol on the changes of these indicators. Results: Erythrocyte GPx activity and serum MDA concentration in STZ - induced diabetic rats was higher than that of normal and lipid metabolism disorder groups (p < 0.001) and effected of the green tea polyphenol. However, no change in erythrocyte SOD activity and plasma TAS level was observed. Conclusions: Green tea polyphenol improved blood antioxidant status in STZ - induced diabetic rats.
Diabetes Mellitus ; Tea ; Camellia sinensis ; Blood ; Oxidants

Background and Objectives. Neuroprotection agents may help improve the outcomes of large vessel ischemic stroke. This study aims to explore the role of Virgin Coconut Oil (VCO), with its well-documented anti-oxidant properties, in neuroprotection after transient occlusion of the extracranial internal carotid artery in a rat model of stroke. Methods. Twenty-three Sprague-Dawley rats were randomized into two groups: 1) control group (n=11) given distilled water, and 2) treatment group (n=12) given virgin coconut oil at 5.15 ml/kg body weight for seven days. Subsequently, the rats underwent transient right extracranial internal carotid artery occlusion (EICAO) for 5 minutes using non-traumatic aneurysm clips. At 4 and 24 hours after EICAO, the animals were examined for neurologic deficits by an observer blinded to treatment groups, then sacrificed. Eight brain specimens (4 from each group) were subjected to histopathologic examination (H & E staining) while the rest of the specimens were processed using triphenyltetrazolium chloride (TTC) staining to determine infarct size and area of hemispheric edema. Results. VCO treatment significantly improved the severity of neurologic deficit (1.42 ± 2.31) compared to the control distilled water group (4.09 ± 2.59) 24 hours after EICAO. Whereas, infarct size and percent hemispheric edema did not significantly differ between the two groups. Conclusion. Prophylactic treatment of VCO is protective against EICAO-induced neurologic deficits in a rat model. VCO shows great potential as a neuroprotective agent for large vessel ischemic stroke. However, more studies are necessary to elucidate the neuroprotective mechanisms of VCO therapy in ischemic stroke.
Coconut Oil ; Oxidants ; Antioxidants ; Neuroprotection ; Ischemia ; Stroke

OBJECTIVETo estimate the impact of copying on the indoor air quality, and to investigate whether ozone emitted during such a process induces pathological oxidative stress and potential oxidative damage in the bodies of operators.

METHODS67 copying operators (CO) and 67 healthy volunteers (HV) were enrolled in a random control study, in which levels of lipoperoxide (LPO) in plasma and erythrocytes, and levels of vitamin C (VC), vitamin E (VE) and beta-carotene (beta-CAR) in plasma as well as activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) in erythrocytes were determined by spectrophotometric methods.

RESULTSCompared with the HV group, the average values of LPO in plasma and erythrocytes in the CO group were significantly increased (P<0.0001), while those of VC, VE and beta-CAR in plasma as well as those of SOD, CAT and GPX in erythrocytes in the CO group were significantly decreased (P<0.0001). Pearson product-moment correlation analysis showed that with increase of ozone level in copying sites and duration of exposure to ozone, the values of LPO in plasma and erythrocytes in the bodies of operators were gradually increased,while those of VC, VE, beta-CAR, SOD, CAT and GPX were decreased in the same manner. Odds ratio (OR) of risk of biochemical parameters reflecting potential oxidative damage of the copying operators ranged from 4.440 to 13.516, and 95% CI of OR was from 2.113 to 34.061. Reliability coefficient (alpha) of the biochemical parameters used to reflect the potential oxidative damage of the operators was 0.8156, standardized item alpha=0.9929, P<0.0001.

CONCLUSIONFindings in the present study suggest that there exist a series of free radical chain reactions and pathological oxidative stress induced by high dose ozone in the operators, thereby causing potential oxidative and lipoperoxidative damages in their bodies.

Adult ; Copying Processes ; Erythrocytes ; Female ; Humans ; Male ; Occupational Exposure ; Odds Ratio ; Oxidants, Photochemical ; analysis ; toxicity ; Oxidative Stress ; Ozone ; analysis ; toxicity ; Risk Assessment

OBJECTIVE: To determine the histocompatibility and histoconstancy of bovine jugular vein conduit (BJVC) treated by dye-mediated photooxidation following decellularization before and after implantation in Wistar rats. METHODS: Each of 20 fresh bovine jugular veins with a retained native valve procured from a slaughterhouse was cut into 4 trial patches with valves, which were randomly divided into 4 groups. The 4 groups were treated respectively by dye-mediated photooxidation(DMP), glutaraldehyde(GA), decellularization(DC), and dye-mediated photooxidation following decellularization (DC+DMP). One of the trial patches in each group was implanted subcutaneously in the same Wistar rat. Two months later, all trial rats were killed and the specimens were retrieved. Tissue protein extraction was used to estimate the cross-linked degree of BJVC treated by dye-mediated photooxidation following decellularization. To observe the morphologic properties of the specimens, HE staining and electron microscopes were used. RESULTS: Compared with others, the patches in the DC+DMP group were flexible, stretched, and relatively intact; lining endothelium was comparatively smooth; collagen fiber structure was slightly loose intact; and many cells were uniformly infiltrated in all layers. CONCLUSION BJVC treated by dye-mediated photooxidation following decellularization is superior to others in histocompatibility, and the rate of degradation can be regulated by the degree of dye-mediated photooxidation.
Animals ; Bioprosthesis ; Blood Vessel Prosthesis ; Cattle ; Cell Separation ; Jugular Veins ; anatomy & histology ; transplantation ; ultrastructure ; Materials Testing ; Oxidants, Photochemical ; pharmacology ; Oxidation-Reduction ; Rats ; Rats, Wistar

OBJECTIVE: To investigate the mechanisms underlying ozone-induced inactivation of poliovirus type 1 (PV1). METHODS: We used cell culture, long-overlapping RT-PCR, and spot hybridization assays to verify and accurately locate the sites of action of ozone that cause PV1 inactivation. We also employed recombinant viral genome RNA infection models to confirm our observations. RESULTS: Our results indicated that ozone inactivated PV1 primarily by disrupting the 5'-non-coding region (5'-NCR) of the PV1 genome. Further study revealed that ozone specifically damaged the 80-124 nucleotide (nt) region in the 5'-NCR. Recombinant viral genome RNA infection models confirmed that PV1 lacking this region was non-infectious. CONCLUSION In this study, we not only elucidated the mechanisms by which ozone induces PV1 inactivation but also determined that the 80-124 nt region in the 5'-NCR is targeted by ozone to achieve this inactivation.
5' Untranslated Regions ; Animals ; Cercopithecus aethiops ; Genome, Viral ; drug effects ; Oxidants, Photochemical ; pharmacology ; Ozone ; pharmacology ; Poliovirus ; drug effects ; Vero Cells ; Virus Inactivation