The MIC method was carried out in vitro using a twofold dilution technique approved by CLSI (Clinical and Laboratory Standard Institute).16 The concentrations of the CS and HTCC standard samples ranged from 5 mg/mL to 0.00122 mg/mL. A serial sample was obtained by mixing 1 mL of the standard sample with 9 mL of anaerobic medium. A total of 100 lL of 0.5 McFarland standard organism suspension was dropped onto the surface of the blood agar medium plate. The blood plates were incubated in the anaerobic chamber (Thermo Life Science, USA) under an atmosphere of 80% N2, 10% H2, and 10% CO2 with deoxidized palladium for 72 h.