ABSTRACT Title of dissertation: THE CHEMICAL ECOLOGY OF HYDRASTIS CANADENSIS L. (RANUNCULACEAE):EFFECTS OF ROOT ISOQUINOLINE ALKALOIDS ON THE HYDRASTIS ENDOPHYTE, FUSARIUM OXYSPORUM
The extracts of Coptidis japonica (rhizoma), Eugenia caryophyllata (flower), Rheum palmatum (rhizoma), Magnolia officinalis (cortex) and Rhusjavanica (galla rhois) potently inhibited the growth of Helicobacter pylori (HP). However, these herbal extracts showed no inhibitory effect on HP urease except Galla rhois. Among the components separated from active herbal extracts by silica gel column chromatography, the inhibitory effects of decursinol angelate and decursin on the growth of HP were the most potent, followed by magnolol, berberine, cinnamic acid, decursinol and gallic acid. Minimum inhibitory concentrations (MICs) of decursin and decursinol angelate were 6-20 microg/ml.