The Research Of Fungi Chitin Synthase Inhibitor From Plant

Antifungal activities of ethanol extracts from 89 species of traditional Chinese medicines were tested using Filter-Paper Disc Diffusion Method on two-layer plates against Saccharomyces cerevisiae YFK32, Staphyloccocus aureus, Bacillus subtilis, and Escherichia coli. 14 species of herb extracts exhibited obvious growth inhibition against Saccharomyces cerevisiae YFK32, the strongest inhibition appeared in the extracts of Salvia (Salvia miltiorrhiza Bunge), Anemarrhena (Anemarrhena asphodeloides Bunge), and licorice (Glycyrrhiza uralensis Fisch), all of the three showed the same MIC of 0.078 mg/mL. 9 species of herb extracts had relatively weaker but specific inhibition against Saccharomyces cerevisiae YFK32.The activities of Chinese medicines extracts to inhibit fungal chitin synthase were screened by using the positive model (constructed by other student in this lab.) in which the growth inhibition of yeast in Calcofluor white medium can be rescued by Chinese medicines extracts. Total of 11 kind Chinese medicines extracts including No.35 were found by this screening. The activities of Chinese medicines extracts to inhibit fungal chitin synthase were further screened by using the deletion strain of Saccharomyces cerevisiae Whu2a (the nagative model constructed by other student in this lab.), in which CHS I、III or CHS I、II were deleted to screening chitin synthase inhibitors, respectively. The two strain were named CHT020 and CHT003. The result showed 9 kinds of herb extracts including No.17 have stronge inhibition against CHT020, and No.35 showed strong effect in both the positive and nagative screening models. Furthermore, the chitin levels in Whu2a cells treated or untreated by No.35 were determined as 33.7190 mg/g and 17.3791 mg/g . Above experiments indicated that No.35 had activities to inbibit fungal chitin synthase, and it is needed to further study this Chinese medicines extracts as chitin synthase inhibitor.We also studied the influences of some herb extracts on the effects of germination of Botrytis cinerea. Through microscope observation of germination of extract-treated Botrytis cinerea spores on a thin layer of water agar, three kinds of herb extracts, including Salvia, Coptis, and licorice, exhibited inhibition to a certain degree. The highest inhibition rate was 85.90%, found in the extract of Coptis.