Studies Of Bacteriostasis Activity And Mechanism Of The Extract FromDandelion Against Fusarium

A plant, Dandelion widely distributed in China, was investigated for its disinfectanted activity against Fusarium, crude extract extracted by respective immersion, was separated by extraction and purified through column chromatograghy, and its active constitute,L3, was separated. Its activities to active methods and inhibitory mechanism were studied. The results indicated:1. Dandelion powder in three solvent extraction, the extraction rate in descending order of methanol> chloroform> petroleum ether. Respectively,7.23%,3.02%,1.57%. Simultaneous determination of the extract on the biological activity of Fusarium oxysporum, the results showed that:Dandelion methanol extracts concentration2mg· mL-1at96h on the tested strains was inhibited by67.26%; against spore germination was93.22%. One of the mycelial growth and spore germination EC50of0.77mg· mL-1and0.37mg· mL-1. Therefore, the choice of methanol extract of dandelion for further separation.2. The antifungal activities of the extract fromMethanol extracts of Dandelion extract three different findings showed that:the highest rate of methanol extraction, followed by chloroform, petroleum ether extraction lowest rate. On the biological activity of extracts tracking test showed that methanol extract relative Fusarium oxysporum and have higher spore germination inhibition were82.71%and96.90%. Followed by chloroform, petroleum ether worst, respectively61.69%79.30%and40.00%,69.48%, the choice of methanol extracts for further separation.3.Methanol extract was purified by column chromatography and TLC analysis, the combined stream of the same fraction obtained after9, and the resulting fraction9show biological activity determination, L3has a high biological activity, the inhibition rate was94.5396h%of Fusarium oxysporum and spore germination EC50of0.21mg· mL-1and0.26mg·mL-14.By Fusarium oxysporum cell membrane permeability and in vivo chitinase and protease activity found dandelion methanol extracts can increase its cell membrane permeability, resulting in leakage of substances in the body, rapid activation of chitinase enzyme activity and protein directly inhibit bacteria hyphae and spores.Experimental results show that dandelion extract on Fusarium oxysporum has a strong antibacterial activity, the development of new botanical pesticide has a good prospect.