Extraction Of Anti-tomato Late Bligh Compositions From Scutellaria Baicalensis Georgi And Study On Its Antibacterial Mechanism

In this thesis, scutellaria baicalensis georgi was used as test material to inhibit Tomato Late Bligh and the diameter of inhibition zone was tested. The methods of extracting of the antibacterial substances from scutellaria baicalensis georgi and effect factors were studied. A primary antimicrobial mechanism was studied on methanol extract of Scutellaria baicalensis in biochemical and microstructure level. The results were as follows:1.Reflux extraction method with univariate and orthogonal tests has been used to determine the extraction conditions:Anhydrous ethanol is used as the solvent, the ratio of solid to liquid is 1:45(m:v), the active ingredients have been extracted for 1 hour under 65℃,and 2 times for extractions showed the best inhibition activities for the Tomato Late Bligh. The maximum diameter of the inhibition zone has reached 34.3mm.The minimum concentration is 15.7mg/mL.2.The influence factors of bacteriostatic effect of extracts from Scutellaria baicalensis georgi:acidic condition has no effect on antibacterial activity, the antibacterial activity under the alkaline condition is declined, Na+、K+、Ca2+、Mg2+ can reduce antibacterial activity, Zn2+、Fe3+ can increased antibacterial activity. High temperature and sucrose have little concentration on the antibacterial activity of extracts from Scutellaria baicalensis georgi, the antibacterial activity of extracts from Scutellaria baicalensis georgi under the ultraviolet irradiation is declined.3. Qualitative test results:the extracts contain flavonoids, terpenoids, phenols, volatile compounds.4. Scanning electron microscope and transmission electron microscope revealed ultrastructural modifications caused by extracts from scutellaria baicalensis georgi. Cytodern and cellular organ of the Tomato Late Bligh were markedly altered, the bacteria cell wall was damaged, contents of cell flew out.5. Conductivity method was developed for the determination of cell membrane permeability, antibacterial substances maybe damaged the cell membrane as early, electrolyte flew out, nutrient solution conductivity increased. Fluorescence labeling method was developed for the determination of cell membrane integrity, the integrity of the cell membrane was damaged by high antibacterial liquid concentration. High concentrations of antimicrobial substances can greatly destroy the cell structure of the selected bacteria, the macromolecular substances leaked.6. The bacteria DNA were analyzed by fluorescence spectrum, and the effective components of extracts from Scutellaria baicalensis georgi interacted with DNA, reduced its activity, changed its conformation.