The Mechanism of Bisdemethoxycurcumin Enhances Conventional Antibiotics against Methicillin-Resistant

Methicillin-resistant Staphylococcus aureus (MRSA) infection has posed a serious threat to public health, therefore, the development of new antibacterial drugs is imperative. Bisdemethoxycurcumin (BDMC) is a curcumin analog that exists in nature and possesses extensive pharmacological actions. This review focuses on investigating the antibacterial activity of BDMC alone or in combination with three antibiotics against MRSA. We determined the minimal inhibitory concentration of BDMC, with a broth microdilution assay, and the value against all six strains was 7.8 μg/mL. The synergistic effect of BDMC combined with the antibiotics was determined using a checkerboard dilution test and a time–kill curve assay. The results showed that the antimicrobial effect of BDMC combined with antibiotics was superior to treatment with that of a single agent alone. We examined the antibacterial activity of BDMC in the presence of a membrane-permeabilizing agent and an ATPase-inhibiting agent, respectively. In addition, we analyzed the mecA transcription gene and the penicillin-binding protein 2a (PBP2a) level of MRSA treated with BDMC by quantitative RT-PCR or Western blot assay. The gene transcription and the protein level were significantly inhibited. This study demonstrated that BDMC has potent antibacterial activity, and proved that BDMC may be a potential natural modulator of antibiotics.