The Research On Antibacterial Mechanism And The Active Ingredients Of Angelica Sinensis

Studies on the antibacterial mechanism and the active ingredients of acetone extract of Angelica sinensis were investigated. The antibacterial activities were determined by the broth microdilution method, and morphological changes of Escherichia coli and Staphylococcus aureus were observed through the electron microscope scanning method, meanwhile, the changes of dehydrogenase activies were surveyed with colorimetric method. Using broth microdilution method, minimum inhibitory concentrations (MICs) of various parts were determined. According to the results, the acetone extract has antibacterial effect, and the MIC values againce E. coli and Pseudomonas aeruginosa are2500μg·mL-1, MICs against of the other test strains are1250μg·mL-1. It is showed that cells of the negative control group is complete, uniform, smooth-faced under the scanning electron microscopy. Otherwise, the cells of experimental groups are obviously distorted and lose the original form. The wall and cell membrane of some test bacteria ruptures and the contents spill over. It is indicated that the extract can inhibit2kinds of dehydrogenase enzyme of the test bacteria, and the activity of dehydrogenase gradually weakens with increasing drug concentration. It also shows that E.coli dehydrogenase are more sensitive to drugs compared with Staphylococcus aureus. Petroleum ether part has the strongest antibacterial activity. MIC value was1250mg·mL-1against Streptococcus agalactiae while others were625mg·mL-1against the other five bacteria. Except for Pseudomonas aeruginosa, MICs of ethyl acetate part were1250mg·mL-1against other test bacteria. N-butanol and water parts have no activities against the test bacteria.14compounds were isolated by silica gel and sephadex LH-20column chromatograph from petroleum ether part of Angelica sinensis. Six compounds were indetified by1H-NMR,13C-NMR and ESI-MS. The compounds are Z-6,7-dihydroxy ligustilide(1),β-sitosterol(2), Daucosterine(3), myristate-acid(4),(3S)-butylphthalide(5), Coniferyl ferulate(6), respectively. Structures of remaining compounds and activity of monomer compounds will be determined in the follow-up work.