Extraction And Separation Of Anti-tomato Late Bligh Compositions From Aloe And Study On Its Influencing Factors Of The Antibacterial Effect

In this thesis, aloe was used as test material to inhibit Tomato Late Bligh and the diameter of inhibition zone was tested. The methods of extracting and separating of the antibacterial substances from aloe and effect factors were studied. The results were as follows:1. Using the solvent extraction method the best extraction conditions were determined:acetone was used as the solvent, the ratio of solid to liquid was1:15, extracted for6hours under45℃, and3times for extractions. The inhibition zone diameter was29.67mm.2. The minimum inhibitory concentration of aloe extract was1.57mg/mL.3. The results showed that The aloe extract had the best antibacterial activity in the neutral condition, Ca2+、Zn2+、Fe3+、could increase the antibacterial activity. Antibacterial activity was reduced through treatment by high temperature、ultraviolet light、sugar.4. The active constituents of the aloe extract contained anthraquinones, organic acids, tannin, sugar, terpenoids, did not have alkaloids, saponins and flavonoids.5. The extraction was followed by the petroleum ether, ethyl ether, ethyl acetate, n-butanol. The result showed that the best antibacterial activity was n-butyl alcohol extract. Six fractions were obtained through separated it by column chromatography on silica and only fraction2and6had antibacterial activity, and lower than that of n-butanolpart.