ABSTRACT
The antibacterial activity of an extract and several fractions of Sophora flavescens (S. flavescens) root alone and in combination with antibiotics against oral bacteria was investigated by checkerboard assay and time-kill assay. The minimum inhibitory concentration/minimum bactericidal concentration (MIC/MBC) values for all examined bacteria were 0.313-2.5/0.625-2.5 µg/mL for the n-BuOH fraction, 0.625-5/1.25-10 µg/mL for the EtOAc fraction, 0.25-8/0.25-16 µg/mL for ampicillin, 0.5-256/1-512 µg/mL for gentamicin, 0.008-32/0.016-64 µg/mL for erythromycin, and 0.25-64/0.5-128 µg/mL for vancomycin. The n-butanol (n-BuOH) and ethyl acetate (EtOAc) fractions exhibited stronger antibacterial activity against oral bacteria than other fractions and extracts. The MICs and MBCs were reduced to between one half and one quarter when the n-BuOH and EtOAc fractions were combined with antibiotics. After 24 h of incubation, combination of 1/2 MIC of the n-BuOH fraction with antibiotics increased the degree of bactericidal activity. The present results suggest that n-BuOH and EtOAc extracts of S. flavescens root might be applicable as new natural antimicrobial agents against oral pathogens.
Subject(s)
1-Butanol/chemistry , Anti-Bacterial Agents/pharmacology , Bacteria/drug effects , Mouth/microbiology , Plant Extracts/pharmacology , Plant Roots/chemistry , Sophora/chemistry , Drug Synergism , Humans , Microbial Sensitivity TestsABSTRACT
BACKGROUND: Sophora flavescens AITON (Leguminosae) is a typical traditional Korean medical herb considered to exhibit antibacterial, anti-inflammatory, and antipyretic effects, and is also used for the treatment of skin and mucosal ulcers, sores, diarrhea, gastrointestinal hemorrhage, arrhythmia, and eczema. OBJECTIVE AND DESIGN: This study examined the inhibitory effects of sophoraflavanone G (SF) of S. flavescens on the bacterial fibrillar protein, Antigen I/II (AgI/II)-N recombinant protein isolated from Streptococcus mutans(rAg I/II)-induced production of nitric oxide (NO) and prostaglandin E2 (PGE2). The investigation was focused on whether SF could inhibit the production of proinflammatory mediators such as nitric oxide (NO) and prostaglandin (PG) E2 as well as the expression of inducible nitric oxide synthase (iNOS), cyclooxygenase (COX)-2, tumor necrosis factor (TNF)-a, interleukin (IL)-6, nuclear factor (NF)-κB and mitogen-activated protein kinases (MAPKs) in rAgI/II-stimulated RAW 264.7 cells using Griess reagent, Enzyme linked immunosorbent assay (ELISA), and Western blotting analysis. RESULTS: SG significantly inhibited the production of NO and PGE2 and pro-inflammatory cytokines, such as interleukin (IL)-1ß, IL-6, and tumor necrosis factor α in Ag I/II-N-stimulated RAW264.7 cells, which were mediated by the down-regulation of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2) expression. The SF inhibited the phosphorylation of IκB-α, nuclear translocation of p65, and subsequent activation of NF- κB in the rAgI/II-stimulated cells. In addition, the SF suppressed the rAgI/II-stimulated activation of ERK MAPK as well as the MAPK inhibitor significantly reduced the rAgI/II-induced production of NO and PGE2. CONCLUSION: Collectively, we suggest that the SF inhibits the expression and production of inflammatory mediators by blocking the ERK MAPK mediated pathway and inhibiting the activation of NF-κB.
Subject(s)
Antigens, Bacterial/metabolism , Antigens, Surface/metabolism , Dinoprostone/biosynthesis , Flavanones/pharmacology , MAP Kinase Signaling System/drug effects , Macrophages/drug effects , Nitric Oxide/biosynthesis , Streptococcus mutans/drug effects , Animals , Anti-Inflammatory Agents/pharmacology , Cyclooxygenase 2/biosynthesis , Cyclooxygenase 2/metabolism , Cytokines/metabolism , Interleukin-1beta/metabolism , Interleukin-6/metabolism , Macrophages/immunology , Macrophages/metabolism , Macrophages/microbiology , Mice , NF-kappa B/metabolism , Nitric Oxide Synthase Type II/biosynthesis , Nitric Oxide Synthase Type II/metabolism , Protein Kinase Inhibitors/pharmacology , RAW 264.7 Cells , Streptococcus mutans/immunology , Streptococcus mutans/metabolism , Tumor Necrosis Factor-alpha/metabolismABSTRACT
BACKGROUND: Baicalein is one of the major flavonoids in Scutellaria baicalensis Georgi, which has long been used in Asia as herbal medicine. Several biological effects of baicalein, such as antiviral, anti-inflammatiom, anti-hepatotoxicity, and anti-tumour properties, have been reported. OBJECTIVE AND DESIGN: In this study, the antibacterial activities of baicalein were investigated in combination with ampicillin and/or gentamicin against oral bacteria. RESULTS: Baicalein was determined with MIC and MBC values ranging from 80 to 320 and 160 to 640 µg/mL against oral bacteria. The range of MIC50 and MIC90 were 20-160 µg/mL and 80-320 µg/mL, respectively. The combination effects of baicalein with antibiotics were synergistic (FIC index <0.375-0.5 and FBCI <0.5) against oral bacteria. Furthermore, a time-kill study showed that the growth of the tested bacteria was completely attenuated after 1-6 h of treatment with the MIC50 of baicalein, regardless of whether it was administered alone or with ampicillin or gentamicin. CONCLUSION: These results suggest that baicalein combined with other antibiotics may be microbiologically beneficial and not antagonistic.