Isolation, Extraction And Purification Of Fermention From S. Avermitilis NEAU 1069

Doramectin, developed as a new generation of macrolide antiparasitic drugs in the nineties of the 20th century. It is considered one of the best drugs in the present avermectins. It takes cyclohexane carboxylic acid as the precursor, fermented by a new recombinant strain of Streptomyces avermitilis. It is used extensively for the treatment of endo-and ecto-parasites of livestock and companion animals. The primary evaluation of its in vivo antiparasitic activity was carried out using a rat Trichostrongylus colubriformis model and a rabbit Psoroptes cuniculi model. In addition, when compared to ivermectin, doramectin has lower toxic to soil invertebrates, higher bioavailability and longer duration of preventive efficacy.In this paper, the doramectin-producing strain (Streptomyces avermitilis NEAU 1069) for shaking flask fermentation, and then dried mycelium was extracted with methanol. The concentrated extract was further isolated by silica gel column chromatography, ODS column chromatography, HPLC and other chromatographic means, yielded twenty-two avermectin compounds at last. Nine compounds of them were discovered for the first time, and the compounds were examined by proton and carbon NMR spectroscopy, mass spectrometry.According to the avermectins compounds naming rules from Jerry, etc. The novel nine compounds were named respectively for the fist time:They are 23-Keto-25-cyclohexyl-Deo-Phenolic-AVM B2-AGL (1),25-cyclohexyl-Deo-Phenolic-AVM B1-AGL (2),25-cyclohexyl-Deo-Phenolic-AVM B2-AGL (3),8-demethyl-25-cyclohexyl-Deo-Phenolic-AVM B1-AGL (4),8-demethyl-25-cyclohexyl-Deo-Phenolic-AVM B2-AGL (5), 23-Keto-Deo-Phenolic-AVM B2a-AGL (6),25-cyclohexyl-Deo-Phenolic-AVM B2-MS (7), 25-cyclohexyl-Deo-AVM A2-MS (8),13-Ketone-25-cyclohexyl-Deo-AVM A2-AGL (9).In addition, the key signals of the'H-NMR spectrum and their mass spectrometry (ESI-MS) data of the 13 known compounds are also described. These known compounds include the eight compounds, the initial discovery of avermectin compounds, two compounds with a cyclohexane at the position of C-25; compounds 20 and 21 with the 1H-NMR and 13C-NMR data of for the first time, and the compound 22, oligomycin A.