Identification of caffeic acid and rutin by UHPLC MS/MS and antioxidant activity of Commelina erecta Lineu. in cell culture.

The Commelina erecta L. (C. erecta) also known as erva-de-santa-luzia is reported by local population to have medical properties against some pathological conditions. In this study, two extracts of C. erecta leaves (aqueous and ethanolic) were phytochemically analysed and evaluated for their in-vitro antioxidant activities by DPPH, TBARS, NO assays and cell viability assays. The ultra-high performance liquid chromatography followed by tandem mass spectrometry analysis showed the presence of rutin and caffeic acid in aqueous and ethanolic extract. The total polyphenols in aqueous and ethanolic extracts found were 142.7 ± 3.0 and 123.1 ± 5.8 µg/mL of GAE, respectively. The ethanolic extract (5 mg/mL) inhibits TBARS by 33.8%, and the aqueous extract (5 mg/mL) exhibited scavenger property against nitric oxide derivatives to an extent of 77.8%. In cell culture, both extracts improved cell survivability under H2O2 induced oxidative stress. Thus, C. erecta extract is a good candidate to become a phytotherapic medicine.

A phase I trial of thermal sensitization using induced oxidative stress in the context of HIPEC.

BACKGROUND: Inducing oxidative stress under hyperthermic conditions significantly decreases tumor cell growth in a murine model of human colon cancer carcinomatosis. This phase I study examines the safety and pharmacokinetics of induced oxidative stress by the addition of hydrogen peroxide (H2O2) to the perfusate in patients undergoing cytoreduction and hyperthermic intraperitoneal chemotherapy (HIPEC) for advanced abdominal-only malignancies. METHODS: Patients with advanced colon or appendiceal malignancies underwent maximal cytoreduction followed by HIPEC with mitomycin C (MMC). In addition, H2O2 was added to the perfusate at three concentrations (n = 3/level, 0.05, 0.075, 0.1 %). A control group consisted of patients perfused with MMC alone (n = 3). Perfusate, serum MMC, and H2O2 levels were measured, as were tissue levels of MMC. RESULTS: Twelve patients were enrolled onto this trial. The median (range) peritoneal carcinomatosis index was 13 (3-20) requiring a median operative time of 6.3 (4-8.5) h. The median postoperative length of stay was 9 (5-34) days, with six patients requiring readmission within 30 days. Similar complications were observed at all three H2O2 levels, as well as in the control group. One patient required reexploration for a colon perforation (control group), and three patients developed enterocutaneous fistulas (0.075 % H2O2, 0.1 % H2O2 and control group). There were no operative mortalities. CONCLUSIONS: Hyperthermic intraperitoneal chemotherapy with induced oxidative stress after maximal cytoreduction is well tolerated. On the basis of the encouraging toxicity profile after cytoreduction and HIPEC with induced oxidative stress, a phase II trial to verify activity is indicated.

Effect of light activation on tooth whitening efficacy and hydrogen peroxide penetration: an in vitro study.

OBJECTIVES: To determine the effect of light activation on tooth whitening efficacy and hydrogen peroxide penetration into the pulp cavity and correlate tooth color change with penetration levels. METHODS: Extracted human canines (40) were randomized into four groups, Group A: placebo gel, Group B, placebo gel with light activation, Group C: 40% hydrogen peroxide gel, and Group D: 40% hydrogen peroxide gel with light activation. Treatment was performed three times, at 1-week intervals. Hydrogen peroxide penetration (HPP) was estimated spectrophotometrically and specimen color measured using the Vita Easy Shade Compact at baseline, after whitening, 1-h, 1-day, 1-, 4-, 8-, 12-, 16-, 20-, and 24-week post-whitening. Color change was measured per Commission Internationale de l'Eclairage methodology. ANCOVA was performed to compare color change and HPP level among the four groups. Partial nonparametric correlations between color change and HPP levels were performed with rank transformations. Tests of hypotheses were two-sided with alpha level of 0.05. RESULTS: Greater HPP was observed in Groups C and D compared to Groups A and B (p<0.001). Highest overall color change (ΔE*ab) values after treatment were observed in Group D and remained higher than Groups A-C (p<0.01). Changes in lightness and in the yellow-blue dimension (ΔL* and Δb*) were higher in Groups C and D compared to Groups A and B from post-whitening until 24 weeks (p<0.05). HPP levels were not correlated to color change (p>0.05). CONCLUSIONS: Light activation enhanced whitening efficacy without affecting hydrogen peroxide penetration levels.

Influence of chemical activation of a 35% hydrogen peroxide bleaching gel on its penetration and efficacy--in vitro study.

OBJECTIVES: The aim of this study was to evaluate the effects of chemical activation of hydrogen peroxide (HP) gel on colour changes and penetration through the tooth structure. METHODS: One hundred and four bovine incisors were used. One dentine (CD) disc and one enamel-dentine (ED) disc were prepared from each tooth. They were positioned over artificial pulpal chambers and the bleaching was performed with an experimental 35% HP gel. Two control and six experimental groups were prepared. In the positive control group (PC) no chemical activator was used. In the negative control group (NC) the specimens did not receive any bleaching. Each experimental group received a different chemical activator (manganese gluconate-MG; manganese chlorite-MC; ferrous sulphate-FS; ferrous chlorite-FC; and mulberries root extract-MRE). After the bleaching procedure a sample of solution was collected from the artificial pulpal chamber and the HP concentration was measured. The data were analysed using ANOVA, Tukey's, and Dunnett's tests. RESULTS: The groups MG and FS showed a significantly lower penetration of HP than the PC group. For the parameter Delta E, all the groups, with the exception of the group MRE, showed a significantly higher means in relation to the PC group in ED colour. For dentine colour, just the groups MG and FS had significant differences in relation to PC. CONCLUSIONS: The addition of MG and FS decreases the penetration of HP. The chemical activation using metal salts tested was effective in increasing the bleaching effect.

Studies on modulation of DNA integrity in Fenton's system by phytochemicals.

Chronic exposure to oxidative stress especially to highly reactive hydroxyl radicals (HO*) could damage biomolecules, particularly DNA, that in turn would accelerate onset of degenerative diseases. In the present study a few standard phytochemicals (vitamin C, gallic acid, catechin, apigenin, naringenin and naringin) and plant extracts (Hippophae rhamnoides kernel (HRK), Syzygium cumini kernel (SCK) and Punica granatum pericarp (PGP)) were evaluated for their potential to protect/damage DNA in Fenton's system using in vitro models. The results indicated a significant DNA protective effect for naringin and PGP whereas other phytochemicals/extracts showed DNA damaging effect similar to or more than that of control value. The phytochemicals/extracts were also evaluated for their antioxidant and iron chelation properties. In general, the phytochemicals/extracts with high antioxidant activity but without iron chelation capacity failed to protect DNA in Fenton's system, suggesting that iron chelation was an essential requirement for the phytochemicals studied here to retard HO* generation by Fenton's reaction. This was demonstrated by the high iron chelation capacity of naringin and PGP (83.67% and 68.67% respectively) and their DNA protective effect. Commonly consumed phytochemicals such as vitamin C and gallic acid with their high reducing power and at higher physiological concentration, could regenerate free iron for Fenton's reaction leading to DNA damage as shown here.

The bleaching depth of a 35% hydrogen peroxide based in-office product: a study in vitro.

OBJECTIVES: The aim of the present study was to quantify the penetration of 35% hydrogen peroxide into enamel and dentine and to relate this to the resultant shade change of the tooth. METHOD: The crowns of 24 caries and developmental defect free human maxillary incisors were stained internally with a standardised tea solution. Twelve specimens were power bleached with light activated 35% hydrogen peroxide and 12 placed in water; both exposure times were 30min. Three different shade assessment methods (Vita shade guide [SG], shade vision system [SVS] and a chromometer) were employed prior to, after tea staining and after power bleaching/water treatments. Twelve specimens each from the bleach group and the water control water group were sectioned mesio-distally. An additional 12 specimens from the bleach and the control group were sectioned labio-palatally. The stain area for each specimen was measured using image analysis software. RESULTS: With tea staining, the mean changes in Vita shade guide units (SGU) ranged from 3.66 to 8.33. With the SVS system changes of 3.66-9 units were seen. Chromometer readings showed that following bleaching the L* values moved in the direction of black (3.8-6.7) and a* and b* values were in the red (0.3) and yellow (1.5) direction, respectively. Samples bleached and sectioned mesio-distally showed stain coverage of 28.6-39.4%, while palatal sections showed stain coverage of 58-72%. Control samples, whether sectioned mesio-distally or labio-palatally, showed staining throughout the dentine (97-100% coverage). CONCLUSION: A 35% hydrogen peroxide in-office bleaching gel demonstrated bleaching into dentine of uniform depth.

Effect of calcium hydroxide as a supplementary barrier in the radicular penetration of hydrogen peroxide during intracoronal bleaching in vitro.

AIM: To examine pH changes in the cervical external root surface, when calcium hydroxide was used as a supplementary barrier to the protective base material during intracoronal bleaching. METHODOLOGY: Twenty-eight single-rooted human premolars extracted for orthodontic reasons were instrumented with K-Flex files, obturated with gutta-percha and subjected to thermocatalytic bleaching. The teeth were divided into four groups. In group A, a glass-ionomer cement barrier was placed at the cemento-enamel junction (CEJ) level and in group C, the barrier was placed 1 mm apical to the CEJ. In groups B and D, Ca(OH)2 was placed in contact and apical to the glass-ionomer cement at the CEJ and 1 mm apical to the CEJ, respectively. The teeth were placed in vials containing distilled water and the pH values of the medium surrounding the teeth were recorded after 1, 2, 4, 10 and 15 days, following renewal of the medium. RESULTS: The pH in the medium became acidic in all groups. No statistically significant differences existed between groups for all the experimental days (P = 0.790). CONCLUSION: The placement of Ca(OH)2 as a supplementary barrier during intracoronal bleaching did not have a significant effect in reversing the acidic pH created at the external root surface in vitro. Its potential effect during these procedures in vivo needs to be further investigated.

[Escape of hydrogen peroxide and oxygen from the root canal]. / Untersuchungen zum Austritt von Wasserstoffperoxid und Sauerstoff aus dem Wurzelkanal.

In vitro investigations demonstrate that hydrogen peroxide, like the oxygen emitted from the root canal, escapes into the area around the root. The amount measurable was dependent on the concentration, the amount of time that the hydrogen peroxide was left in the root canal and the patency of the foramen apicale. The growth of the Staphylococcus aureus (SG 511) was restricted in the area around those roots whose root canal contained a 5% solution of hydrogen peroxide.