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Item Inhibitory efects of 7-epiclusianone on glucan synthesis, acidogenicityand biofilm formation by Streptococcus mutans.(2008) Murata, Ramiro Mendonça; Almeida, Luciana Salles Branco de; Yatsuda, Regiane; Santos, Marcelo Henrique dos; Nagem, Tanus Jorge; Rosalen, Pedro Luiz; Koo, HyunThe aim of this study was to examine the effects of 7-epiclusianone, a new prenylated benzophenone isolated from the plant Rheedia gardneriana, on some of the virulence properties of Streptococcus mutans associated with biofilm development and acidogenicity. The synthesis of glucans by glucosyltransferases B (GTF B) and C (GTF C) was markedly reduced by 7-epiclusianone showing more than 80% inhibition of enzymatic activity at a concentration of 100 mgmL 1. Doublereciprocal analysis (Lineweaver–Burk plots) revealed that the inhibition of GTF B activity was noncompetitive (mixed) while GTF C was inhibited uncompetitively. The glycolytic pH drop by S. mutans cells was also disrupted by 7-epiclusianone without affecting the bacterial viability, an effect that can be attributed, in part, to inhibition of F-ATPase activity (61.1 3.0% inhibition at 100 mgmL 1). Furthermore, topical applications (1-min exposure, twice daily) of 7-epiclusianone (at 250 mgmL 1) disrupted biofilm formation and physiology. The biomass (dryweight), extracellular insoluble polysaccharide concentration and acidogenicity of the biofilms were significantly reduced by the test agent (Po0.05). The data show that 7-epiclusianone disrupts the extracellular and intracellular sugar metabolism of S. mutans, and holds promise as a novel, naturally occurring compound to prevent biofilm-related oral diseases.Item Spectroscopic investigation of organotin (IV) derivatives of 7-epiclusianone : a preliminary in vitro antitumor evaluation of HN-5 human carcinoma cell.(2009) Vieira, Flaviana Tavares; Maia, José Roberto da Silveira; Vilela, Marcelo José; Ardisson, José Domingos; Santos, Marcelo Henrique dos; Oliveira, Tânia Toledo de; Nagem, Tanus JorgeA series of organotin(IV) compounds have been prepared by reaction with 7-epiclusianone (Epi), a natural product extracted from fruits of Rheedia gardneriana. This compound has an interesting motif with several coordinating sites for metal-ligand bond formation, and in solution, it shows a keto-enol tautomerism. The NMR of the organotin(IV) derivatives has revealed intramolecular hydrogen bonding, indicating that the keto-enol tautomerism of 7-epiclusianone is not involved upon coordination of those, but the absence of this bonding type in the case of the SnCl4 derivative suggests a strong interaction. The Mössbauer spectroscopy has revealed five- and six-fold coordination for the organotin(IV) and SnCL» derivatives in the solid state. However, in solution all tin complexes have six-fold coordination, as shown by "9Sn NMR. The overall data point out that the organotin(IV) precursors SnClxPri4_x (x = 1, 2) are weakly bonded to the 7- epiclusianone, except the SnC^. Bioassay in vitro of the substance test [SnClPh3(£/7/)] (1) has been investigated using two epithelial cells: normal MDCK from canine kidney, and IIN-5 from a human carcinoma of the tongue. The results clearly demonstrate that the time for cellular reproduction has been reduced in the presence of the substance test.