Litsea glauca oil%Staphylococcus aureus%inhibition zone%minimum inhibitory concentration%GC-MS

To compare the antibacterial activities of Litsea glauca oils from different origins,six samples(labeled as 1#and 2#)from Jiangxi,Hunan,and Guangdong provinces were conducted antibacterial experiments against Staphylococ-cus aureus.Comparative studies of inhibition zone,minimum inhibitory concentration(CMIC),and chemical composition analysis were conducted using filter paper method,constant broth dilution method,and Gas chromatography-mass spec-trometry(GC-MS)analysis method.The results showed that:(1)L.glauca oils fromJiangxi 1#and 2#had the same antibacterial zones as the control group against S.aureus.The diameters of antibacterial zones in the other samples,ranked as follows:Hunan 2#L.glauca oil(10.0±0.3 mm),Hunan1#L.glauca oil(10.3±0.1 mm),Guangdong 1#L.glauca oil(10.3±0.2 mm),and Guangdong 2#L.glauca oil(12.6±0.4 mm);(2)The CMIC of Jiangxi 1#and 2#L.glauca oils,and Hunan 2#L.glauca oil were all 32 μL/mL,while that of Hunan 1#L.glauca oil,Guang-dong 1#and 2#L.glauca oils were all 16 μL/mL;(3)The GC-MS analysis results showed that all L.glauca oils from three regions contain citral,with Guangdong(96.21%),Hunan(48.10%),and Jiangxi(19.77%)in descending order of content.In summary,the conclusions of the antibacterial zone and MIC are basically consistent,that is,Guangdong L.glauca oils have the best antibacterial activities,followed by Hunan,while Jiangxi L.glauca oils have the worst antibacterial activities.The above antibacterial mechanism can be explained by the results of GC-MS,which may be due to the proportional relationship between the contents of citral/limonene and their antibacterial activities.