Eun-Kyung Jung

Antibacterial activity of sophoraflavanone G Isolated from the roots of Sophora flavescens against methicillin‐resistant Staphylococcus aureus

In this study, sophoraflavanone G obtained from Sophora flavescens was evaluated against 10 clinical isolates of methicillin‐resistant Staphylococcus aureus (MRSA), either alone or in combination with ampicillin or oxacillin, via checkerboard assay. At the end point of an optically clear well, the minimum inhibitory concentrations (MICs) ranged from 0.5 to 8 µg/ml for sophoraflavanone G, from 64 to 1024 µg/ml for ampicillin, and from 256 to 1024 µg/ml for oxacillin. The combination of sophoraflavanone G and ampicillin or oxacillin yielded a fractional inhibitory concentration index ranging from 0.188 to 0.375, thereby indicating a principally synergistic effect. The synergistic interaction was verified by time‐kill studies using sophoraflavanone G and/or antibiotics. Thirty minutes of treatment with sophoraflavanone G with ampicillin or oxacillin resulted in an increase in the rate of killing in units of CFU/ml to a greater degree than was observed with Sophoraflavanone G alone. These findings indicated that the application of the tested sophoraflavanone G alone or in combination with antibiotics might prove useful in the control and treatment of MRSA infections. Copyright

Relationship between the activities of daily living, oral health-related quality of life and dementia: ADL and OHRQoL and dementia

The aim of the present study was to investigate the association between the activities of daily living and the oral health‐related quality of life and dementia in older adults.

Antimicrobial activity of the chloroform fraction of Drynaria fortunei against oral pathogens

Drynaria fortunei (D. fortunei), widely used in traditional Korean medicine, is reportedly effective in treating inflammation, hyperlipidemia, bone fractures, oxidative damage, arteriosclerosis, rheumatism, and gynecological diseases. The objective of this study was to evaluate the antibacterial effects of the chloroform fraction of D. fortunei (DFCF) and assess the synergistic effects of DFCF with antibiotics against bacterial pathogens. This was carried out by calculating the minimal inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) and performing checkerboard dilution test and time-kill assays. The MICs/MBCs for DFCF, ampicillin, and gentamicin against all oral strains were >39-2,500/5,000 μg/mL, 0.25-64/0.25-64 µg/mL, and 0.5-256/1-512 µg/mL, respectively. DFCF exhibited the highest activity against the periodontic pathogens Prevotella intermedia and Porphylomonas gingivalis. DFCF in combination with ampicillin showed a strong synergistic effect against oral bacteria (fractional inhibitory concentration (FIC) index ≤0.5), whereas on combining with gentamicin, it reduced the on half-eighth times than used alone (FICI ≤ 0.5). DFCF combined with ampicillin or gentamicin killed 100% of most tested bacteria within 3-4 h. The results of this study demonstrate the antimicrobial and synergistic activity of DFCF and antibiotics against oral pathogens.

Synergistic Effect between Baicalein and Antibiotics against Clinic Methicillinand Vancomycin-Resistant Staphylococcus aureus

Baicalein is one of the major flavonoids in Scutellaria baicalensis Georgi, which has long been used in several biological effects, such as antiviral, anti-inflammation, anti-hepatotoxicity, and anti-tumor properties, have been reported. In this study, baicalein demonstrated strong antibacterial activity against clinic isolated methicillin and vancomycin-resistant Staphylococcus aureus (MRSA and VRSA) in this experiment. Baicalein was determined against clinic isolated MRSA 1-16 with MIC and MBC values ranging from 64 to 256 and 64 to 512 μg/ml; for MSSA 1-2 from 128 and 256 μg/ml and 128 and 512 μg/ml; for VRSA 1-2 from 64 and 128 μg/ml and 64 and 512 μg/ml, respectively. The range of MIC50 and MIC90 of baicalein were 16-64 μg/ml and 64-256 μg/ml, respectively. The combination effects of baicalein with antibiotics were synergistic (FIC index <0.5) against most of tested clinic isolated MRSA, MSSA, and VRSA except additive, MRSA 7 in oxacillin and MRSA 8 and 15 in vancomycin (FIC index <0.625-0.75). Furthermore, a time-kill study showed that the growth of the tested bacteria was completely attenuated after 2-6 h of treatment with the ½ MIC of baicalein, regardless of whether it was administered alone or with ampicillin, oxacillin, or vacomycin. The results suggest that baicalein could be employed as a natural antibacterial agent against multidrug-resistant pathogens infection.