Luteolin potentiates the effects of aminoglycoside and β-lactam antibiotics against methicillin-resistantStaphylococcus aureus in vitro.
Methicillin-resistantStaphylococcus aureus(MRSA) infection has become a serious clinical problem worldwide, and alternative natural or combination drug therapies are required for its treatment. The aim of the present study was to examined the antimicrobial activity of luteolin (LUT) against MRSA. Luteolin is a polyphenolic flavonoid compound with a wide spectrum of biological activities. The antimicrobial activities of LUT and the antibiotics ampicillin (AM), oxacillin (OX) and gentamicin (GT), used alone or in combination, were evaluated against five clinical MRSA isolates and two reference strains using a minimum inhibitory concentration (MIC) assay, MTT colorimetric assay, checkerboard dilution test and time-kill assay. The MIC of LUT against all strains was found to be 62.5 µg/ml. The combinations of LUT and antibiotics exhibited a synergistic effect against MRSA in the majority of cases, as determined by the checkerboard method. Time-kill curves revealed that a combination of LUT with AM, OX or GT significantly reduced bacterial counts, which dropped below the lowest detectable limit after 24 h. These results indicate that LUT potentiates the effects of β-lactam and aminoglycoside antibiotics against MRSA.
Department of Oriental Pharmacy, College of Pharmacy and Wonkwang-Oriental Medicines Research Institute, Wonkwang University, Iksan, Jeonbuk 570-749, Republic of Korea.
Dae-Ki
DK
Joung
Department of Oriental Pharmacy, College of Pharmacy and Wonkwang-Oriental Medicines Research Institute, Wonkwang University, Iksan, Jeonbuk 570-749, Republic of Korea.
Ok-Hwa
OH
Kang
Department of Oriental Pharmacy, College of Pharmacy and Wonkwang-Oriental Medicines Research Institute, Wonkwang University, Iksan, Jeonbuk 570-749, Republic of Korea.
Yun-Soo
YS
Seo
Department of Oriental Pharmacy, College of Pharmacy and Wonkwang-Oriental Medicines Research Institute, Wonkwang University, Iksan, Jeonbuk 570-749, Republic of Korea.
Tian
T
Zhou
Department of Herbal Crop Research, National Institute of Horticultural & Herbal Science, Rural Development Administration, Eumsung, Chungbuk 369-873, Republic of Korea.
Young-Seob
YS
Lee
Department of Herbal Crop Research, National Institute of Horticultural & Herbal Science, Rural Development Administration, Eumsung, Chungbuk 369-873, Republic of Korea.
Sin-Hee
SH
Han
BK21 Plus Team, Professional Graduate School of Oriental Medicine, Wonkwang University, Iksan, Jeonbuk 570-749, Republic of Korea.
Su-Hyun
SH
Mun
BK21 Plus Team, Professional Graduate School of Oriental Medicine, Wonkwang University, Iksan, Jeonbuk 570-749, Republic of Korea.
Ryong
R
Kong
BK21 Plus Team, Professional Graduate School of Oriental Medicine, Wonkwang University, Iksan, Jeonbuk 570-749, Republic of Korea.
Ho-Jun
HJ
Song
Department of Oriental Medicine Resources, Sunchon National University, Suncheon, Jeonnam 540-742, Republic of Korea.
Dong-Won
DW
Shin
Department of Oriental Pharmacy, College of Pharmacy and Wonkwang-Oriental Medicines Research Institute, Wonkwang University, Iksan, Jeonbuk 570-749, Republic of Korea.
Dong-Yeul
DY
Kwon
aminoglycoside antibiotics; iuyeolin; methicillin-resistant Staphylococcus aureus; β-lactam