Abstract:The minimal inhibitory concentration(MIC) and minimal bactericidal concentration(MBC) of santalol to methicillin-resistant Staphylococcus aureus(MRSA) standard strain USA300 were determined by colony counting and broth dilution methods, respectively. The effect of santalol on USA300 cell membrane and cell wall was measured by conductivity and DNA content in liquid. The effect of santalol in the process of soluble protein metabolism of USA300 was studied by SDS-PAGE. The ultrastructure of USA300 treated with santalol was observed by scanning electron microscope and transmission electron microscope. The effect of santalol in the formation of USA300 biofilm was determined by crystal violet staining. The results showed that santalol could inhibit the growth and reproduction of USA300. The corresponding MIC and MBC were 32 and 64 μg/mL, respectively. Compared with the control group, the electrical conductivity of the bacteria treated with 64 μg/mL santalol for 1 hour increased 3.40%±0.54%; the intracellular DNA mass concentration of bacteria treated with 64 and 32 μg/mL santalol for 6 h increased significantly, while the soluble protein decreased significantly after 2 h and 6 h of treatment with 64, 32 and 16 μg/mL santalol(P<0 01). The micrographs of scanning electron microscope and transmission electron microscope showed that the cell proliferation had obvious abnormality with no changes on the USA300 cell membrane and cell wall. The results showed that the formation of USA300 biofilm could be inhibited significantly by giving santalol with subinhibitory concentration. In summary, santalol could significantly reduce the soluble protein content in the bacteria by interfering with the protein metabolism process, and affecting the life activities of bacteria. Santalol has great potential in the development of new anti-MRSA drugs.