Study On Antimicrobial Activity And Chemical Constituents Of Essential Oil From Michelia Figo Spreng

Magnolia figo Spreng was used as the raw material in this research. The essential oils were extracted respectively from the flowers and leaves of M. figo. The essential oils were extracted by steam distillation. The antimicrobial activities of the flowers and leaves essential oils on bacteria and fungi were tested with plate counts and filter paper methods. The antibacterial stabilities of the two essential oils were tested through diffent pH, temperature and UV treatments. The antimicrobial activities of the essential oils in gas condition on bacteria and fungi were tested, and gas antisepticise experiments to fresh pork and tofu were tested synchronously. At last, the chemical constituents of the flowers and the leaves essential oils were analyzed by GC-MS. The results were showed as follows:1. The antimicrobial effect of the flowers essential oil on Bacillus sabtills,Escherichia coli and Mucor racemosus were fine, and their inhibitory rates were up to 70.36%,60.24%,65.52%. There were certain antimicrobial effect on Staphylococcus aureus and Aspergillus flavus, but no antimicrobial effect on Rhizopus oryzae.2. The antimicrobial effect of the essential oil from the leaves on Escherichia coli, Staphylococcus aureus and Bacillus sabtills were very fine. The LC50 were:0.64μL·mL-1,0.77μL·mL-1,0.62μL·mL-1, and the MIC were:18.9μL·mL-1,20.1μL·mL-1,15.2μL·mL-1. But the antimicrobial rates of Mucor racemosus, Aspergillus flavus and Rhizopus oryzae were lower than 50%.3. The inhibition stabilities of the two essential oils were tested through diffent pH, temperature and UV treatments. The results showed that the two kinds of essential oils had good thermal stability and UV stability. These results provided reference for the using of the two kinds of essential oils in industry.4. There were certain inhibitory effects to common bacteria and fungi in gas conditions of the essential oils, and could postpone the modification time of pork and tofu effectively. 5. Thirty kinds of compounds were separated and identified respectively from the flowers essential oil, and twenty three kinds of compounds were separated and identified respectively from the leaves essential oil. Six organic ester compounds which decided the fragrant type of the flowers were identified, and the main antimicrobial compounds of the essential oils were preliminary analyzed.