摘要:
在以荔枝霜疫霉菌为指示菌的生物活性测定导向跟踪下,运用TLC、硅胶柱层析、反相硅胶柱层析和凝胶柱层析等分离纯化方法,从开口箭(Tupistra chinensis)甲醇提取物的乙酸乙酯分部萃取物中分离纯化得到2个抗菌化合物。经现代光谱(MS、IR、1D NMR和2D NMR)分析,确定化合物1为1β,2β,3β,4β,5β,7α-六羟基螺甾-25(27)-烯-6-酮,化合物2为螺甾-25(27)-烯-1β,2β,3β,4β,5β,6β,7α-七醇。离体抗菌活性测定化合物1和化合物2抑制荔枝霜疫霉菌(Peronophythora litchii)孢子囊萌发的EC50分别为100.28 mg·mL-1和124.37 mg·mL-1。用质量浓度为500 mg·mL-1的两个化合物分别处理后接种霜疫霉菌,供试荔枝果实的发病率分别为16.7%和18.9%。
Abstract:
The methanol extract of Tupistra chinensis showed antifungal acitivity against the sporangium germination of Peronophythora litchii.Bioassay-guided fractionation together with various chromatographic procedures(TLC,silica column chromatography,RP-18 reverse phase chromatography and Sephadex LH-20 gel chromatography)led to the isolation of two bioactive sapogenins from ethyl acetate phases of the methanol extract of T.chinensis.By means of spectroscopic analysis(MS,IR,1D NMR and 2D NMR),their structures were identified as 1β,2β,3β,4β,5β,7α-hexahydroxyspirost-25(27)-en-6-one(1) and spirost-25(27)-ene-1β,2β,3β,4β,5β,6β,7α-heptol(2).Bioassay in vitro revealed that the EC50 values of compounds 1 and 2 against sporangium germination of P.litchii were 100.28 mg·mL-1 and 124.37 mg·mL-1,respectively.Treatment with 500 mg·mL-1 of compounds 1 and 2 before inoculated with P.litchi,the incidences of downy blight disease of the tested litchi fruits were just 16.7% and 18.9%.
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