Browsing by Author "Yatsuda, Regiane"

Now showing 1 - 3 of 3
  • No Thumbnail Available
    Item
    Antimicrobial activity of Rheedia brasiliensisand 7-epiclusianone against Streptococcus mutans.
    (2008) Almeida, Luciana Salles Branco de; Murata, Ramiro Mendonça; Yatsuda, Regiane; Santos, Marcelo Henrique dos; Nagem, Tanus Jorge; Alencar, Severino Matias de; Koo, Hyun; Rosalen, Pedro Luiz
    This in vitro study evaluated the antimicrobial activity of extracts obtained from Rheedia brasiliensis fruit (bacupari) and its bioactive compound against Streptococcus mutans. Hexane, ethyl-acet ate and ethanolic extracts obtained (concentrations ranging from 6.25 to 800mg/ml) were tested against S. mutans UA1 59 through MIC /MBC assays. S. mutans5-days -old biofilm s were treat ed with the active extra cts (100 MIC ) for 0, 1, 2, 3 an d 4 h (time-k ill) and plate d for colony counting (CFU/m l). Active extracts were submitted to exploratory chemical analyses so as to isolate and identify the bioactive compound using spectroscopic method s. The bioactive compo und (concentration s ranging from 0.625 to 80mg/ml) was then tested through MIC /MBC assays . Pee l and seed hexane extracts showed antimicrobial activity against planktonic cells at low concentrations and were thus selected for the time kill test. These hexane extracts reduced S. mutans biofilm viability after 4 h, certifying of the bioactive compo und presence. The bioactive compound identified was the polyprenylated benzophenone 7-epiclusianone, which showed a good antimicrobial activity at low concentrations (MIC : 1.25–2 .5 mg/ml; MBC: 10–20mg/ml). The results indicated that 7-epi clusian one may be used as a ne w agent to control S. mutans biofilms; however, more studies are needed to further elucidate the mechanisms of action and the anticariogenic potential of such compound found in R. brasiliensis.
  • No Thumbnail Available
    Item
    Antiproliferative effect of benzophenones and their infl uence on cathepsin activity.
    (2010) Murata, Ramiro Mendonça; Yatsuda, Regiane; Santos, Marcelo Henrique dos; Kohn, Luciana K.; Martins, Felipe Terra; Nagem, Tanus Jorge; Alencar, Severino Matias de; Carvalho, João Ernesto de; Rosalen, Pedro Luiz
    The antiproliferative activity of two prenylated benzophenones isolated from Rheedia brasiliensis, the triprenylated garciniaphenone and the tetraprenylated benzophenone 7-epiclusianone, was investigated against human cancer cell lines. The antiproliferative activity on melanoma (UACC-62), breast (MCF-7), drug-resistant breast (NCI-ADR), lung/non-small cells (NCI460), ovarian (OVCAR 03), prostate (PC03), kidney (786-0), lung (NCI-460) and tongue (CRL-1624 and CRL-1623) cancer cells was determined using spectrophotometric quantifi cation of the cellular protein content. The effect of these benzophenones on the activity of cathepsins B and G was also investigated. Garciniaphenone displayed cytostatic activity in all cell lines, whereas 7- epiclusianone showed a dose-dependent cytotoxic effect. The IC50 values for cell proliferation revealed that 7-epiclusianone is more active than garciniaphenone against most of the cell lines. Furthermore, the antiproliferative effects demonstrated by garciniaphenone and 7-epiclusianone were related to their cathepsin inhibiting properties. In conclusion, 7-epiclusianone is a promising naturally occurring agent which displays multiple inhibitory effects which may be working in concert to inhibit cancer cell proliferation in vitro. The putative pathway by which 7-epiclusianone affects cancer cell development may involve cathepsin inhibition.
  • No Thumbnail Available
    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, Hyun
    The 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.