Preliminary Study On The Extraction Of Active Antibacterial Components In Pteris Multifda Poir And The Bacteriostasis

Chinese traditonal drug is the treasure of traditional Chinese medicine,and it has drawn extensive attention from domestic and foreign experts of medicine circles for thousands of years. Pteris Multifda Poir has broad-spectrum bacteriostasis as a traditional Chinese medicinal plants. With the development of the intensive aquaculture, drug resistance of Escherichia coli is becoming increasingly serious, which brings huge losses to livestock. This article makes a preliminary study on the extraction of active antibacterial components and antibacterial activity in Pteris Multifda Poir, in order to provide a theoretical reference of extracting, purifying and identifying the monomer of active antibacterial components in Pteris Multifda Poir.1. Selecting solvent for Pteris Multifda Poir extract. Using tube double dilution method to assay MIC and MBC for Escherichia coli of five kinds of organic solvents, dimethyl Sulfoxide(DMSO), dimethylformamide(DMF), acetone, acetonitrile and ethanol. As a result, DMSO was selected as the effective solvent for the active antibacterial components in Pteris Multifda Poir as its MIC and MBC for Escherichia coli was 12.5% and 50%.2. Optimizing the extraction technology of the active antibacterial components in Pteris Multifda Poir. The extraction technology was optimized through single factor test and L18(35) orthogonal test, with the active components in Pteris Multifda Poir on the inhibition of Escherichia coli as evaluation index, using solvent refluxing method. Orthogonal test is based on single factor test with the affecting factors: ethanol concentration, temperature, liquid ratio, extracting times and time, for extracting active antibacterial components in Pteris Multifda Poir. The optimum extraction process was established as follows: ethanol concentration of 70%, liquid ratio of 1:30, extraction temperature of 50℃, extracting times of 3 times, extracting time of 0.5 hours. After validation, the average total flavonoids is 69.33 mg/g, the average bacterial inhibition ring in diameter is 18.67±0.03 mm, the extraction rate was 19.78%.3. Crude separation of the active antibacterial components in Pteris Multifda Poir. Tracking the polar of the active antibacterial components in Pteris Multifda Poir by liquid- liquid extraction, N-butanol layer was chosen as the object of study. Using systematic pretest to analyze chemical composition in N-butanol layer, it may contain organic acids, alkaloids, flavonoids, anthraquinones, cardiac glycosides and so on, and may not contain phytosterols, terpenoids, coumarins, lactone and other ingredients.4. Antibacterial effect of N-butanol layer in Pteris Multifda Poir and its effect on cell membranes. N-butanol layer’s MIC to Escherichia coli, chicken salmonella and staphylococcus aureus are 12.5 mg/m L、25 mg/mL、12.5 mg/m L、12.5 mg/m L, and MBC are 50 mg/m L、50 mg/mL、50 mg/mL、25 mg/m L. Inhibitory curves show that the growth of Escherichia coli was inhibited in the 1MIC and 2MIC concentrations, and Escherichia coli was killed after 4 hours and 8 hours respectively. By measuring the electrical conductivity, the conductivity rising until 8 h in the 1MIC concentrations of N-butanol layer crude extracts, it shows that N-butanol layer crude extracts can damage the cell membrane of Escherichia coli, and cause the electrolytes seeps from cells.