Int. J. Mol. Sci. 2012, 13(7), 8210-8218; doi:10.3390/ijms13078210
Isojacareubin from the Chinese Herb Hypericum japonicum: Potent Antibacterial and Synergistic Effects on Clinical Methicillin-Resistant Staphylococcus aureus (MRSA)
1
Research Center for Natural Medicines, Kunming General Hospital, PLA, Kunming 650032, China
2
School of Pharmacy, Guiyang Medical University, Guiyang 550004, Guizhou, China
3
School of Basic Medical Sciences, Yunnan Traditional Chinese Medical College, Kunming 650500, China
4
Center for Infectious Diseases, Kunming General Hospital, PLA, Kunming 650032, China
*
Author to whom correspondence should be addressed.
Received: 7 May 2012 / Revised: 31 May 2012 / Accepted: 18 June 2012 / Published: 3 July 2012
(This article belongs to the Section Biochemistry, Molecular and Cellular Biology)
Abstract
Through bioassay-guided fractionation of the extracts from the aerial parts of the Chinese herb Hypericum japonicum Thunb. Murray, Isojacareubin (ISJ) was characterized as a potent antibacterial compound against the clinical methicillin-resistant Staphylococcus aureus (MRSA). The broth microdilution assay was used to determine the minimal inhibitory concentrations (MICs) and minimal bactericidal concentrations (MBCs) of ISJ alone. The results showed that its MICs/MBCs ranged from 4/16 to 16/64 μg/mL, with the concentrations required to inhibit or kill 50% of the strains (MIC50/MBC50) at 8/16 μg/mL. Synergistic evaluations of this compound with four conventional antibacterial agents representing different types were performed by the chequerboard and time-kill tests. The chequerboard method showed significant synergy effects when ISJ was combined with Ceftazidime (CAZ), Levofloxacin (LEV) and Ampicillin (AMP), with the values of 50% of the fractional inhibitory concentration indices (FICI50) at 0.25, 0.37 and 0.37, respectively. Combined bactericidal activities were also observed in the time-kill dynamic assay. The results showed the ability of ISJ to reduce MRSA viable counts by log10CFU/mL at 24 h of incubation at a concentration of 1 × MIC were 1.5 (LEV, additivity), 0.92 (CAZ, indifference) and 0.82 (AMP, indifference), respectively. These in vitro anti-MRSA activities of ISJ alone and its synergy with conventional antibacterial agents demonstrated that ISJ enhanced their efficacy, which is of potential use for single and combinatory therapy of patients infected with MRSA. View Full-TextKeywords:
anti-MRSA activity; Hypericum japonicum; Isojacareubin; MIC; synergy
▼
Figures
This is an open access article distributed under the Creative Commons Attribution License (CC BY 3.0).
Share & Cite This Article
MDPI and ACS Style
Zuo, G.-Y.; An, J.; Han, J.; Zhang, Y.-L.; Wang, G.-C.; Hao, X.-Y.; Bian, Z.-Q. Isojacareubin from the Chinese Herb Hypericum japonicum: Potent Antibacterial and Synergistic Effects on Clinical Methicillin-Resistant Staphylococcus aureus (MRSA). Int. J. Mol. Sci. 2012, 13, 8210-8218.
Related Articles
Article Metrics
Comments
[Return to top]
Int. J. Mol. Sci.
EISSN 1422-0067
Published by MDPI AG, Basel, Switzerland
RSS
E-Mail Table of Contents Alert