龙胆草中6-去甲氧基-7-甲基茵陈色原酮分离和波谱表征

为研究龙胆草地上部分的化学成分,利用硅胶柱色谱对其乙醇提取物进行了分离纯化,根据理化性质和波谱方法鉴定化合物的结构,分离得到6-去甲氧基-7-甲基茵陈色原酮(Ⅵ)和其他5种已知化合物:β-香树脂醇(Ⅰ)、β-谷甾醇(Ⅱ)、β-香树脂醇乙酸酯(Ⅲ)、乌苏醇(Ⅳ)、齐墩果酸(Ⅴ).其中化合物Ⅵ属首次从龙胆科植物中分离得到的具有2-苯氧基色原酮骨架的天然酚类成分,对其1D和2D NMR谱的特征及EI质谱主要碎片的可能裂解方式进行了讨论,并利用单晶X射线衍射方法对其晶体结构进行了分析.结果表明化合物Ⅵ属正交晶系,Pbca空间群,晶胞参数a=1.291 83(19)nm,b=0.721 19(15)nm,c=2.923 7(5)nm,α=90°,β=90°,γ=90°,V=2.723 9(8)nm3,Z=8,Dc=1.464 g/m3,μ=0.114 mm-1,F(000)=1 248.B环平面与A/C环平面的两面角为99.6°,分子间存在π-π堆积作用.

Isolation and spectra characterization of 6-demethoxy-7- methylcapillarisin from Gentiana scabra Bunge

To study the chemical constituents of aerial part of Gentiana scabra Bunge,the plant material was extracted with ethanol,and the constituents were separated and purified from the ethanol extraction by silica gel column chromatography.Their structures were identified as 6-demethoxy-7-methylcapillarisin (Ⅵ) and five other compounds,β-Amyrin(I),β-Sitosterol (II),β-Amyrin acetate (Ⅲ),Uvaol (IV) and Oleanolic acid (V) on the basis of physicochemical properties and spectral methods.Among them,Compound Ⅵ was isolated from Gentianaceae family for the first time.Its characterization of 1D and 2D NMR spectra and possible fragmentation pathway in EI-MS were discussed.The crystal structure of Compound Ⅵ was determined to be orthorhombic and Pbca space group by X-ray crystallographic analysis.Crystal data are as follows:a=1.291 83(19)nm, b=0.721 19(15)nm,c=2.923 7(5)nm,α=90°,β=90°,γ=90°,V=2.723 9(8)nm~3,Z=8,D_c=1.464 g/m~3,μ=0.114 mm~(-1),F(000)=1 248.The dihedral angle between B ring and A/C ring is 99.6°.There are π-π stacking interactions between molecules.