Effects of low concentration fluoride released from fluoride-sustained-releasing composite resin on the bioactivity of Streptococcus mutans.

This study aimed to determine the effects of the low concentration of fluoride sustained-released from the composite resin on properties of Streptococcus mutans (S. mutans). The proliferation, adhesion, biofilm formation, and lactic acid production of the bacterium were investigated after the treatment with fluoride from the composite resin. The activity and expression of ATPase, glucosyltransferase (GTF), and enolase were also determined by colorimetric assay and western blot analysis. Fluoride from the sustained-releasing composite resin significantly inhibited biofilm formation, adhesion, and acid production of S. mutans but did not influence the growth and ATPase activity of the bacterial strain. Fluoride-sustained-releasing composite resin inhibited adhesion, biofilm formation, and acid production of S. mutans through the suppression of GTF expression as well as the expression and activity of enolase. These resultls suggest the clinical significance of fluoride-sustained-releasing composite resin.

Determination of antioxidant activity and characterization of antioxidant phenolics in the plum vinegar extract of cherry blossom (Prunus lannesiana).

Sakura-cha (salted cherry blossom tea) is a Japanese tea that is traditionally served at celebrations such as wedding ceremonies. The production of Sakura-cha includes the immersion of cherry blossom flowers in Japanese plum vinegar, and through this process, the byproduct (plum vinegar extract of cherry blossom) is obtained. In this study, the antioxidant activity of the plum vinegar extract of cherry blossom was examined. The plum vinegar extract of cherry blossom had a greater superoxide anion scavenging activity compared with red wine, which is a well-known strong antioxidant. Liquid chromatography-mass spectrometry analysis showed that cyanidin-3-glucoside, cyanidin-3-rutinoside, and caffeic acid were the major components in the phenolic extract prepared from plum vinegar extract of cherry blossom, and they possessed superoxide anion scavenging activity. Caffeic acid is mainly responsible for the scavenging activity of phenolic extract; the contributions of cyanidin-3-glucoside and cyanidin-3-rutinoside were minor.

Tyrosinase inhibitory activity of citrus essential oils.

Thirteen kinds of citrus essential oils and their volatile flavor constituents were investigated for tyrosinase inhibitory activity. Eureka lemon, Lisbon lemon, Keraji, and Kiyookadaidai significantly inhibited the oxidation of L-dihydroxy phenylalanine (L-DOPA) by mushroom tyrosinase. Citral and myrcene among volatile flavor constituents of citrus essential oils exhibited tyrosinase inhibitory activities with Ki values of 0.318 and 2.38 mM, respectively. The inhibition kinetics analyzed by a Lineweaver-Burk plot indicated that citral is a noncompetitive inhibitor and myrcene is a competitive inhibitor. These results indicated that citral and myrcene are responsible for the tyrosinase inhibitory activity of citrus essential oils.