| American ginseng(Panax quinquefolium L.) is a species of Panax genus, Araliaceae family, and its dry root used as a famous Chinese medicine. It is originated in Southern Canada and the United States in northern area, and now has introduced in the Northeast China, Hebei, Shandong and other places, with kidney tonifying Qi and blood, nourishing, anti-aging, nourishing the kidney and other effects, is a rare traditional Chinese medicinal materials and the high quality of preserve one’s health care products. Endophytic bacteria is a modern popular in medicine and agriculture research area, Chinese ginseng produced endophytes very rich in resources, worthy of further exploitation.The thesis of Jilin ginseng endophyte separation, screening and identification, which gained two pairs of American ginseng pathogenic fungi have significant antagonistic activity of strain; secondary metabolites and the target strains extraction and separation and structural identification, study its antioxidant activity. Provide a theoretical basis for the development and utilization of ginseng endophyte resources.This paper research content mainly has the following several aspects:(1) Tissue separation was used, 34 strains of endophytic bacteria were obtained from American ginseng root, stem and leaf cultivated in the five American ginseng producing regions of Jilin province. Two antagonist strains have obvious effects on common pathogens of pathogenic fungi and human body, and they were found with its bacteria and sterile fermentation filtration. B3 strain is identified as methyl nutritional Bacillus(Bacillus methylotrophicus), and Bl1 strain is Bacillus subtilis(Bacillus subtilis) with morphological identification and molecular biologymethods, both of them belongs to the bacteria.(2) The improved filter method was adopted to determine the bacteriostatic activity with both of the strains, results show that B3 and Bl1 strains both have strong inhibition activities to E. coli, Staphylococcus aureus and Pseudomonas aeruginosa, especilly have the strongest inhibitory effect to Staphylococcus aureus, and the average bacteriostatic circle diameter reached to 16 mm and 14 mm respectively; but to E. coli the inhibition effect are general, the average bacteriostatic circle diameter reached to 12 mm and 10 mm respectively; To Pseudomonas aeruginosa the effects are less important, the average bacteriostatic circle are 8 mm and 9 mm diameter.(3) Eight compounds were isolated from secondary metabolites in the two endophytic bacteria strains of the American ginseng. Among them, strain B3 has three compounds(compounds 1, 2, 3), strain Bl1 has 5 compounds(compounds 4, 5, 6, 7, 8). They are identified with the spectrum analysis as compounds(1, 2, 3, 4, 5, 8) were alpha d-glucose, ergosterol, mannitol and ginseng saponin Re, carrot glycosides, 2,4,5- trimethyl-1,3-benzodiazepines, but compounds 6 and 7 have not yet identified. Results show that the American ginseng contained a variety of endophytic bacteria and host plants of the same chemical composition.(4) DPPH,ABTS, hydroxyl radical(·OH) removal abilities were evaluated for the antioxidant activity of 8 compounds. The results show that concentration of 8 compounds can be found within the specified range, showed good antioxidant capacity. Among them, compounds(1, 3) on DPPH free radicals and ABTS free radical elimination abilities are better than others, compound 7 has good effects to ABTS radical and hydroxyl free radical(·OH), but the effect on DPPH free radical elimination performance is not obvious. Because compounds(1, 3) have strong antibacterial activity and antioxidant effect, and both of them isolated from the strain B3, the strain B3 compounds has a higher biological activity, the strain B3 is expected in using as a new resource for the research and development of new drugs. |
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