title: In vitro anti-cariogenic activity of dichloromethane fraction from Rheum undulatum L. root.
abstract: This study aimed to evaluate in vitro effects of Rheum undulatum L. root on the development of dental caries, especially its effects on viability, dental plaque formation, and glycolytic acid production of Streptococcus mutans and Streptococcus sobrinus. Methanol extract of Rheum undulatum L. root and its fractions were prepared and tested. Among the test extract and fractions, dichloromethane fraction (DF) showed the most active antibacterial activity (inhibition zone: 13-17 mm) against S. mutans and S. sobrinus in a disc diffusion method. Minimal inhibitory concentrations (MICs) of DF against these bacteria ranged from 0.25 to 0.5 mg/mL. Furthermore, DF significantly inhibited the caries-inducing factors of these bacteria. At sub-MIC levels, DF inhibited in vitro dental plaque formation by S. mutans and S. sobrinus (IC50= 0.079 and 0.142 mg/mL, respectively), which was caused, in part, by the inhibitory effect on the activity of glucosyltransferases. A significant reduction of glycolytic acid production was found at the concentration as low as 0.032 mg/mL for S. mutans and 0.063 mg/mL for S. sobrinus. The possible bioactive compounds that are inducing in vitro anti-cariogenic activity of DF are unknown. Based on the preliminary phytochemical analysis, the activity of DF may be related to the presence of anthraquinones, cardiac glycosides, coumarines, sterols/terpenes, and phenolics. These results indicate that DF is probably useful for the control of dental plaque formation and subsequent dental caries development.
authors.affiliation: Department of Preventive Dentistry, Chonbuk National University, Jeonju, Korea.
authors.forename: Ju-Hee
authors.initials: JH
authors.lastname: Song
authors.forename: Tae-Cheol
authors.initials: TC
authors.lastname: Yang
authors.forename: Kee-Wan
authors.initials: KW
authors.lastname: Chang
authors.forename: Seong-Kyu
authors.initials: SK
authors.lastname: Han
authors.forename: Ho-Keun
authors.initials: HK
authors.lastname: Yi
authors.forename: Jae-Gyu
authors.initials: JG
authors.lastname: Jeon
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D002327:Cariostatic Agents / Q000737:chemistry / Q000494:pharmacology*; D003731:Dental Caries / Q000378:metabolism / Q000382:microbiology / Q000517:prevention & control; D003773:Dental Plaque / Q000378:metabolism / Q000382:microbiology / Q000517:prevention & control*; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology; D005936:Glucans / Q000378:metabolism; D005964:Glucosyltransferases / Q000037:antagonists & inhibitors / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008752:Methylene Chloride / Q000737:chemistry; D008826:Microbial Sensitivity Tests; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D018517:Plant Roots; D012250:Rheum; D012997:Solvents / Q000737:chemistry; D013295:Streptococcus mutans / Q000187:drug effects* / Q000201:enzymology / Q000254:growth & development; D016986:Streptococcus sobrinus / Q000187:drug effects* / Q000201:enzymology / Q000254:growth & development
chemical_list: D000900:Anti-Bacterial Agents; D002327:Cariostatic Agents; D004791:Enzyme Inhibitors; D005936:Glucans; D010936:Plant Extracts; D012997:Solvents; D008752:Methylene Chloride; D005964:Glucosyltransferases