摘要：One hundred thirteen medicinal plants were examined for antibacterial activity against 138 strains of Staphylococcus aureus including 49 strains of methicillin-resistant S. aureus (MASA). The strains were isolated from different speicimens obtained at food borne outbreaks in Osaka city, foods, feces of diarrheal patients or healthy person, or hospital patients. Thirty two medicinal plants produced an inhibition zone around themselves on an agar plate inoculated with 0.05m l of suspension of S. aureus culture and incubated at 37°C for 1 day. To assess antibacterial activiy and obtain a compound possessing this activity, medicinal plants were extracted with dimethyl sulfoxide (DMSO). The extracted solutions of 15 medicinal plants among 113 showed the antibacterial activity when examined by disks charged with the extract on the agar plate inoculated with each strain of S. aureus . Growth of 18 strains of S. aureus including 9 strains of MRSA was examined on agar plates containing DMSO extracts at 1, 0.1, and 0.01%. Only one medicinal plant, Kanzoh (Glycyrrhizae Radix), inhibited the growth of all 18 strains at 1%, but not at 0.1% and 0.01%. The minimum inhibitory concentration (MIC) of the DMSO extract from Kanzoh was determined for 138 strains of S. aureus by the agar dilution method. MIC distributed between 1.0% and 0.13%, and MIC50 or MIC90 which inhibited growth of 50% or 90% of the strains was 0.5%. This value was the same as that obtained from results for MRSA.
