Water Silymarin Antibacterial Active Ingredient And Its Mechanism

silybum marianum, Ageratum genus of Composite, an annual and biennial herb, is easy to grow in rich soil or beach and etc., originated from Europe and planted as a medicinal plant for liver protection after introduced to China in the 1970s. Its medicinal component is silymarin.In recent years, its cholagogic, liver-protective and gastric ulcer treatment effects were reported. However, the reports of studies on its antibacterial active ingredients were rare. In this paper, in order to decide the antibacterial active ingredients of silymarin and to study its antibacterial mechanism, following the fruit of silybum marianum physically squeezed, the extracts were concentrated to paste, then eluted with 30%EtOH,60%EtOH,95%EtOH respectively after degreased by petroleum ether. Finally antibacterial activities of the three elutes were studied. It was concluded that 60%EtOH elute was the antibacterial active ingredient.7 compounds were obtained after being isolated and purified through silica Gel column, ODS column and HPLC column. The chemical structures of the 5 compounds were identified as Silibinin, Quercetin, IsosilybinB, Silydianin and 3,5,7-trihy-droxylchromone. It was the first time that 3,5,7-trihydroxylchromone was separated from silybum marianum.It was proved that the effects of antibacterial active ingredients of silymarin work in the way of wrecking the cell wall or inhibiting the use of protein by experiments such as SDS-PAGE electrophoresis and electron microscopy of the ultra structure changes after drug administrated. Thus the antibacterial mechanism was demonstrated on the one side.In this thesis, preliminary studying chemical compositions and antibacterial mechanism of silymarin, a foundation was laid for further studying on biological activities and designing antibacterial medicines with low dosage.