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 microg/ml for sophoraflavanone G, from 64 to 1024 microg/ml for ampicillin, and from 256 to 1024 microg/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.
Cha
Jeong-Dan
JD
Oral Cancer Research Institute, Yonsei University College of Dentistry, Seoul, South Korea.
Moon
Sang-Eun
SE
Kim
Ji-Young
JY
Jung
Eun-Kyung
EK
Lee
Young-Soo
YS
D000667:Ampicillin / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000302:isolation & purification / Q000494:pharmacology*; D004357:Drug Synergism; D044950:Flavanones / Q000302:isolation & purification / Q000494:pharmacology*; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects*; D008826:Microbial Sensitivity Tests; D010068:Oxacillin / Q000494:pharmacology; D010936:Plant Extracts / Q000494:pharmacology; D018517:Plant Roots / Q000737:chemistry; D029909:Sophora / Q000737:chemistry*; D013997:Time Factors
D000900:Anti-Bacterial Agents; D044950:Flavanones; D010936:Plant Extracts; D000667:Ampicillin; C064849:vexibinol; D010068:Oxacillin