Purification Of Alkaloids From Cynanchum Komarovii And Preliminary Study On Inhibitory Activity Against Fusarium Oxysporum Schlecht

As the pillar of Ningxia economic crops,Wolfberry was paid attention by the government.However,the quality and yield of this traditional Chinese herb are directly and indirectly affected by the bacteria,pests and diseases and environmental and human actions,which wolfberry root rot disease is the most serious disease.Cynanchum komarovii is a poisonous plant distributed in the semi-desert areas of Ningxia.The results of the preliminary research showed that the alkaloids extracted from this plant displayed antifungal activity.In order to find out the active constituents with the inhibition activity against Fusarium oxysporum Schlecht,the alkaloids of C.komarovii were isolated systematically.According to preliminary results of the inhibitory activity,the active ingredient was prepared by pH zone purified countercurrent chromatography,and the factors of instrument and the conditions of separation were also discussed.The main results are as follows:According to the preliminary research results,three compounds were isolated from the total alkaloids of C.komarovii by the classical chromatographic methods and the nuclear magnetic resonance technology.The structures of the two compounds were determined as 7-demethoxylophorine(antofine)and a fatty compound.The content of alkaloids in C.komarovii was 1.63%.With the inhibitory hyphae method,the inhibitory activity against F.oxysporum Schlecht of the total alkaloids and antofine were tested.The results showed that the total alkaloids exhibited the same inhibitory activity against F.oxysporum Schlecht as the commercial agrichemicals at the high concentrations(40μg/m L and 50μg/mL),and suggested that the total alkaloid could be potential for development into botanical pesticide.It is worth noting that antofine,the pure compound,displayed the good inhibitory activity against F.oxysporum at lower concentrations(20μg/mL)and was superior to commercially available chemical pesticides,such as chlorothalonil and carbendazim.Antofine would be used as a new Anti-root rot of plant-derived pesticides or lead compounds for further study.pH zone purified countercurrent chromatography is a liquid-liquid partition chromatography technology.For enrichment and purification antofine from alkaloids,n-hexane-ethyl acetate-methanol-water was selected as the solvent system.The retention rate of the solvent in the instrument and the yield of antofine were taken as the references to optimize the retention agent,rotation rates of the instrument and flow rates.The optimum separation conditions were as following: n-hexane: ethyl acetate: methanol: water(3: 6: 1: 5.5)as solvent system,the rotation speed of the instrument as 650r/min,flow rate2mL/min.After one run with this condition,antofine was obtained 44 mg and the purity of final product was greater than 90%.