扁茎黄芪植株中化学成分的分离鉴定及其抑菌活性

Isolation and identification of chemical constituents of the aerial parts of Astragalus complanatus and their antibacterial activities

为综合开发利用药用植物扁茎黄芪Astragalus complanatus,对其非药用部位的化学成分及抑菌活性进行了初步研究。采用硅胶柱层析和LH-20凝胶层析技术从扁茎黄芪植株中分离鉴定了7个化合物,并测定了各化合物对8种细菌的抑菌活性。根据波谱分析结果,7个化合物分别被鉴定为β-谷甾醇(1)、β-sitostenone (2)、lawsaritol A (3)、3β-羟基-5α,8α-桥二氧麦角甾-6,22-二烯(4)、3′,7-二羟基-2′,4′-二甲氧基异黄烷(5)、D-1-O-甲基肌醇(6)和沙苑子苷(7),所有化合物均为首次从扁茎黄芪植株中分离得到。抑菌活性测定结果表明:化合物5对蜡状芽孢杆菌Bacillus cereus、大肠杆菌Escherichia coli、金黄色葡萄球菌Staphylococcus aureus、枯草芽孢杆菌Bacillus subtilis、白菜软腐病菌Erwinia carotovora、猕猴桃溃疡病菌Pseudomonas syringaepv.actinidiae和烟草青枯病菌Ralstonia solanacearum均有不同程度的抑制作用,其中对猕猴桃溃疡病菌、烟草青枯病菌和白菜软腐病菌的最低抑制浓度(MIC)分别为37.5、18.8和75.0μg/mL。3′,7-二羟基-2′,4′-二甲氧基异黄烷(5)的农用抑菌活性为首次报道。

For the comprehensive utilization of medicinal plant Astragalus complanatus,the chemical constituents of its the non-meidcinal parts and their antibacterial activities were investigated preliminarily.Seven compounds were isolated by using silica gel and LH-20 gel chromatography,and their antibacterial activities against 8 species of bacteria were evaulated.After spectrometric analysis,the obtained compounds were identified asβ-sitosterol(1),β-sitostenone(2),lawsaritol A(3),8-epidioxy-5α,8α-ergosta-6,22 E-dien-3β-ol(4),3′,7-dihydroxy-2′,4′-dimethoxyisoflavan(5),D-1-Omethyl inositol(6)and complanatuside(7).All of the above compounds were isolated from the aerial parts of A.complanatus for the first time.Compound 5 showed inhibition effect on Bacillus cereus,Escherichia coli,Staphylococcus aureus,Bacillus subtilis,Erwinia carotovora,Pseudomonas syringae pv.actinidiae and Ralstonia solanacearum,and the MIC values of compound 5 against three species of plant pathogenic bacteria,including P.syringae,R.solanacearum and E.carotovora,were 37.5,18.8 and 75μg/mL,respectively.To our best knowledge,this is the first report about the inhibition effect of5 on plant pathogenic bacteria.