No abstract

In order to evaluate the actual antioxidant features of foods, beverages and also plasma from patients, a number of assays have been developed in the last few years to determine the so called total antioxidant activity (TAA), intended as the cumulative capacity of a biological sample to scavenge free radicals. Most of the assays partially failed in obtaining a good reproducibility when using plasma because it is composed of a large number of substances, some of which are present at very high concentrations and possess masking features. For these reasons we have improved the widely known ABTS method by means of a FIA system where both temperature and dispersion of sample and reagent were strictly controlled. We found that temperature may be a critical aspect in the measurement of plasma TAA whilst its influence may be less important in the assay of non-complex biological samples. We demonstrated that also the reaction time may be critical, depending on the nature of the substance employed. Data confirmed the high TAA of a methylsalicylate-containing mouthrinse as well as the negligible TAA offered by the chlorhexidine containing one. White wines (Verdicchio) also displayed interesting TAA values. The improved method was useful to screen rapidly, without dilution, with very limited handling of the sample and with high repeatability the TAA of plasma in addition to chemical products, beverages and non-complex biological mixtures.

Reactive oxygen species and antioxidant status in periodontal diseases and periodontal-related pathologies is an item of growing interest. Immunohistochemical approach may be usefully employed in the study of soft tissues affected by periodontal disease, giving valuable information on tissue morphology and vascular proliferation that depends directly on the inflammatory state. In order to study CoQ(10) and vitamin E content in healthy gingiva and in gingivitis a new adaptation to previously published methods for their determination was adopted. During gingivitis tissue displayed a large inflammatory infiltration in the lamina propria and a VEGF positive squamous epithelium. The inflammatory infiltration consisted mainly of lymphocytes, plasma cells and neutrophils. Vitamin E dramatically decreased and CoQ(10) remained unchanged despite the increased amount of cells present in the periodontally affected tissues, indicating that continuous oxidative stress which occurred in these structure affected the antioxidant pattern of the tissue.

Several forms of periodontal diseases (PD) are often associated with modified phagocytosing leukocytes and contemporary free radical production. Host antioxidant defenses could benefit from toothpastes used as adjuncts to counteract plaque-associated bacteria. The aim of the present study was to determine possible antioxidant activity (AA) of 12 differently antioxidant-enriched toothpastes, regardless of their efficacy as antimicrobial agents. Toothpastes were enriched alternatively with sodium ascorbyl phosphate, alpha-tocopherol acetate, pycnogenol, allantoin and methyl salycilate or a mixture of these. AA was tested in a cell-free system with a ABTS-decolorization assay improved by means of a flow injection analysis device. Comet assay, using NCTC 2544 keratinocytes, was performed to test if it was possible to identify any protection against in vitro DNA fragmentation provoked by a challenge with H(2)O(2) in cultures pre-incubated with toothpaste extracts. Only toothpastes containing sodium ascorbyl phosphate displayed clear AA with I(50) values ranging between 50 and 80 mg of toothpaste/ml water. COMET analysis of cells challenged with H(2)O(2) in presence of toothpaste extracts revealed a limited protection exerted by sodium ascorbyl phosphate. The results described herein indicate that toothpastes containing sodium ascorbyl phosphate possess AA. All the data were obtained in systems in vitro and the demonstration of in vivo AA is desirable. These findings could be useful in the treatment and maintenance of some forms of PD and should be considered when arranging new toothpaste formulations.