Preventing hepatocyte oxidative stress cytotoxicity with Mangifera indica L. extract (Vimang).

Vimang is an aqueous extract of Mangifera indica used in Cuba to improve the quality of life in patients suffering from inflammatory diseases. In the present study we evaluated the effects of Vimang at preventing reactive oxygen species (ROS) formation and lipid peroxidation in intact isolated rat hepatocytes. Vimang at 20, 50 and 100 microg/ml inhibited hepatocyte ROS formation induced by glucose-glucose oxidase. Hepatocyte cytotoxicity and lipid peroxidation induced by cumene hydroperoxide was also inhibited by Vimang in a dose and time dependent manner at the same concentration. Vimang also inhibited superoxide radical formation by xanthine oxidase and hypoxanthine. The superoxide radical scavenging and antioxidant activity of the Vimang extract was likely related to its gallates, catechins and mangiferin content. To our knowledge, this is the first report of cytoprotective antioxidant effects of Vimang in cellular oxidative stress models.

Effects of three different infant dentifrices on biofilms and oral microorganisms.

The purpose of this work was to evaluate the effects of infant dentifrices: A--with lactoperoxidase, glucose oxidase and lactoferrin; B--with 1100 ppm of NaF and sodium lauryl sulfate; C--with extract of calendula. The dentifrices were test on biofilms formed in vitro from saliva and dental plaque of infants, using reference strains A. viscosus (ATCC 43146); C. albicans (ATCC 51501); L. casei (ATCC 4646); S. mitis (ATCC 49456); S. mutans (ATCC 25175); S. oralis (ATCC 35037); S. sanguis (ATCC 10586); S. sobrinus (ATCC 27609) and isolated clinically microorganisms C. albicans, S. mitis, S. mutans, S. oralis, S. sanguis, S. sobrinus and Lactobacillus sp. Twenty infants were chosen, who were beginning treatment at the Infants Clinic of the Pediatric Dentistry Department, Federal University of Rio de Janeiro. A pool of unstimulated saliva and a pool of dental plaque were collected from which biofilms were produced. Supernatants from each dentifrice were prepared and concentrated and diluted solutions of the dentifrices and a control sterile diluent were tested against the biofilms produced, for 1 and 3 minutes, and against the microorganisms. The results were statistically analyzed by the ANOVA and Tukey Test. After the exposure of the biofilms produced both from saliva and from dental plaque, to the dentifrice B concentrated and 1/2, for 1 and 3 minutes, the viable microorganisms count (CFU/ml), compared to the controls, was significantly reduced (p < 0.05). However, exposure to the dentifrices A and C concentrated and dentifrice B 1/4 and 1/8, for 1 and 3 minutes, was not significantly lethal to the biofilms. The dentifrices A and C, either concentrated or diluted (1/2 to 1/128) and the dentifrice B in the dilutions 1/16 to 1/128 did not have an antimicrobial effect on any microorganism evaluated. For all the microorganisms evaluated, the dentifrice B concentrated and in the 1/2 dilution showed a significant antimicrobial effect, when compared with the control (p < 0.05).

Hydrogen peroxide is involved in hamster sperm capacitation in vitro.

We have investigated the possibility that the generation of hydrogen peroxide (H2O2) by spermatozoa plays a physiological role during capacitation. Capacitation is defined as the incubation period required for fertilization in mammals. Capacitation culminates in an exocytotic event, the acrosome reaction (AR). Mammalian sperm generate H2O2 during aerobic incubation and do not contain catalase, the enzyme that promotes scavenging of H2O2. In the present work we show that added catalase inhibited the AR, while glucose oxidase (GO), an enzyme that generates H2O2, accelerated the onset of the AR. Direct addition of H2O2 also stimulated the AR; catalase inhibited both the stimulation by GO and by H2O2. The onset of the AR was always preceded by the appearance of hyperactivated motility. The stimulation of the AR by H2O2 was manifest 1-2 h after the addition of H2O2. Catalase added at 3 h of incubation was less effective in inhibiting the AR than catalase added at the beginning. Incubation of sperm with catalase prevented the induction of the AR by the membrane-perturbing lipid, lysophosphatidyl choline. Taken together, these results suggest that H2O2 produced by hamster sperm plays a significant role during capacitation, possibly in membrane reorganization to facilitate the fusion that takes place during exocytosis of the acrosomal contents.