earticle

영어

Cryptotanshinone (CT), a major tanshinone of medicinal plant Salvia miltiorrhiza Bunge, demonstrated effective in vitro antibacterial activity against all isolates MRSA tested in this experiment. The antibacterial activities of CT against isolates MRSAwere assessed using the checkerboard and time-kill methods to evaluate the synergistic effects of treatment with ampicillin or gentamicin. The CT was determined against isolates MRSA with MIC and MBC values ranging from 4 to 16 and 8 to 32 μg/mL; for oxacillin from 4 to 32 and 8 to 64 μg/mL; for ampicillin from 64 to 1024 and 128 to 2048 μg/mL respectively. The range of MIC50 and MIC90 were 1-4 μg/mL and 4-16 μg/mL, respectively. The combination effects of CT with oxacillin were synergistic (FIC index <0.5) against all tested isolates MRSA. The MBCs were shown reducing ≥4-8-fold against 85% isolates MRSA, indicating a synergistic effect as defined by a FBCI of ≤ 0.5. Furthermore, a time-kill study showed that the growth of the tested bacteria was completely attenuated after 3-6 h of treatment with the 1/2 MIC of CT, regardless of whether it was administered alone or with oxacillin or ampicillin. The results suggest that CT could be employed as a natural antibacterial agent against MRSA infection. Acknowledgement: This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Knowledge Economy (MKE-R0002038).