title: Inhibitory effects of Oenothera biennis (evening primrose) seed extract on Streptococcus mutans and S. mutans-induced dental caries in rats.
abstract: BACKGROUND
  Oenothera biennis (evening primrose) seed extract (OBSE) is known to contain polyphenols, which may possess antioxidant activities. Polyphenols extracted from several plants are reported to exhibit cariostatic activities by inhibiting mutans streptococcus growth and glucosyltransferase activities. The purpose of the present study was to examine the inhibitory effects of OBSE on the development of dental caries, both in vitro and in vivo.
  
  
  METHODS
  OBSE was investigated for its inhibitory effects on cellular aggregation, hydrophobicity, sucrose-dependent adherence and insoluble glucan synthesis. Furthermore, biofilm formation was examined in the presence of OBSE, using confocal microscopic imaging. An animal experiment was also performed to examine the in vivo effects.
  
  
  RESULTS
  OBSE induced a strong aggregation of Streptococcus mutans MT8148 cells, while cell surface hydrophobicity was decreased by approximately 90% at a concentration of 0.25 mg/ml. The sucrose-dependent adherence of the MT8148 cells was also reduced by addition of OBSE, with a reduction rate of 73% seen at a concentration of 1.00 mg/ml. Additionally, confocal microscopic observations revealed the biofilm development phase to be remarkably changed in the presence of OBSE. Furthermore, insoluble glucan synthesis was significantly reduced when OBSE was present at concentrations greater than 0.03 mg/ml. In an animal experiment, the caries scores in rats given OBSE (0.05 mg/ml in drinking water) were significantly lower than those in rats given water without OBSE.
  
  
  CONCLUSIONS
  Our results indicate that OBSE has inhibitory activity on dental caries.
authors.affiliation: Department of Pediatric Dentistry, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Matsumoto-Nakano
authors.forename: K
authors.initials: K
authors.lastname: Nagayama
authors.forename: H
authors.initials: H
authors.lastname: Kitagori
authors.forename: K
authors.initials: K
authors.lastname: Fujita
authors.forename: S
authors.initials: S
authors.lastname: Inagaki
authors.forename: Y
authors.initials: Y
authors.lastname: Takashima
authors.forename: M
authors.initials: M
authors.lastname: Tamesada
authors.forename: S
authors.initials: S
authors.lastname: Kawabata
authors.forename: T
authors.initials: T
authors.lastname: Ooshima
mesh_terms: D000818:Animals; D001422:Bacterial Adhesion / Q000187:drug effects; D018441:Biofilms / Q000187:drug effects; D002327:Cariostatic Agents / Q000494:pharmacology / Q000627:therapeutic use*; D003731:Dental Caries / Q000188:drug therapy* / Q000382:microbiology; D005936:Glucans / Q000378:metabolism; D005964:Glucosyltransferases / Q000037:antagonists & inhibitors; D057927:Hydrophobic and Hydrophilic Interactions / Q000187:drug effects; D008297:Male; D031665:Oenothera biennis; D008517:Phytotherapy; D010936:Plant Extracts / Q000494:pharmacology / Q000627:therapeutic use*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012639:Seeds; D013295:Streptococcus mutans / Q000187:drug effects*
chemical_list: D002327:Cariostatic Agents; D005936:Glucans; D010936:Plant Extracts; D005964:Glucosyltransferases