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Evidence-Based Complementary and Alternative Medicine
Volume 2014, Article ID 450572, 16 pages
http://dx.doi.org/10.1155/2014/450572
Research Article

Synergistic Effect between Cryptotanshinone and Antibiotics against Clinic Methicillin and Vancomycin-Resistant Staphylococcus aureus

1Department of Research Development, Institute of Jinan Red Ginseng, Jinan, Republic of Korea
2Department of Oriental Medicine Resources, College of Environmental and Bioresource Sciences, Chonbuk National University, Republic of Korea
3Department of Dental Hygiene, Daegu Health College, Daegu, Republic of Korea
4Department of Nursing, Dong-eui University, Republic of Korea

Received 25 November 2013; Revised 6 February 2014; Accepted 18 February 2014; Published 24 March 2014

Academic Editor: Tai-Long Pan

Copyright © 2014 Jeong-Dan Cha et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Cryptotanshinone (CT), a major tanshinone of medicinal plant Salvia miltiorrhiza Bunge, demonstrated strong antibacterial activity against clinic isolated methicillin and vancomycin-resistant Staphylococcus aureus (MRSA and VRSA) in this experiment. The CT was determined against clinic isolated MRSA 1–16 with MIC and MBC values ranging from 4 to 32 and 8 to 128 μg/mL; for MSSA 1-2 from 16 to 32 μg/mL and 64 to 128 μg/mL; for VRSA 1-2 from 2 to 4 μg/mL and 4 to 16 μg/mL, respectively. The range of MIC50 and MIC90 of CT was 0.5–8 μg/mL and 4–64 μg/mL, respectively. The combination effects of CT with antibiotics were synergistic (FIC index ) against most of tested clinic isolated MRSA, MSSA, and VRSA except additive, MRSA 4 and 16 in oxacillin, MRSA 6, 12, and 15 in ampicillin, and MRSA 6, 11, and 15 in vancomycin (FIC index < 0.75–1.0). Furthermore, a time-kill study showed that the growth of the tested bacteria was completely attenuated after 2–6 h of treatment with the 1/2 MIC of CT, regardless of whether it was administered alone or with ampicillin, oxacillin, or vancomycin. The results suggest that CT could be employed as a natural antibacterial agent against multidrug-resistant pathogens infection.