Bioactive Constituents of Shoot Extracts of Sisymbrium irio L. Against Fusarium oxysporum f. sp. cepae

ABSTRACT: The present study was carried out to check the antifungal potential of Sisymbrium irio L. shoot extract against Fusarium oxysporum f. sp. cepae (FOC). In preliminary bioassays, different concentrations (1 to 5%) of leaf, stem and fruit extracts were evaluated against FOC. All the extracts were effective against the pathogen. However, the leaf extract was found the most effective causing 25-41% decrease in FOC biomass. The fractionation of methanolic leaf extract was done by two organic solvents namely n-hexane and chloroform. Different concentrations (1.56 to 200 mg mL-1) of these fractions were tested against FOC. The n-hexane and chloroform fractions showed inhibitory activity against the pathogen and resulted in 77-93% and 80-96% reduction in biomass of FOC, respectively. GC-MS analysis showed the presence of 24 compounds in n-hexane and 4 compounds in chloroform fraction. In n-hexane fraction, β-sitosterol (18.64%) was the most abundant compound followed by orotic acid, bis(tert-butyldimethylsilyl)-, tert-butyldimethylsilyl ester (12.18%), 10-octadecenoic acid, methyl ester (7.90%) and 1,2-benzenedicarboxylic acid, diisooctyl ester (6.05%). Major compounds identified in chloroform fraction were 1,3-benzenedicarboxylic acid, bis(2-ethylhexyl) ester (50.82%) and di-n-octyl phthalate (33.00%). This study concludes that n-hexane and chloroform fractions of methanolic leaf extract of S. irio contain potent antifungal constituents for the management of FOC.

摘要：本研究旨在考察涩荠（Sisymbrium irio L.）地上部分提取物对尖孢镰刀菌葱专化型（Fusarium oxysporum f. sp. cepae，简称FOC）的抗真菌活性。在初步生物活性测定中，我们以1%至5%的不同浓度梯度的叶片、茎秆及果实提取物，针对FOC开展了抑菌活性评价。结果显示所有提取物均对该病原菌具有抑制作用，其中叶片提取物的抑菌活性最强，可使FOC的生物量降低25%至41%。随后采用正己烷（n-hexane）、三氯甲烷（chloroform）两种有机溶剂对甲醇叶片提取物进行分级分离，并以1.56 mg·mL⁻¹至200 mg·mL⁻¹的不同浓度的各分级组分开展抗FOC活性测试。结果表明，正己烷组分与三氯甲烷组分均表现出显著的抑菌活性，分别可使FOC生物量降低77%至93%、80%至96%。气相色谱-质谱联用（GC-MS）分析结果显示，正己烷组分中共检出24种化合物，三氯甲烷组分中检出4种化合物。正己烷组分中含量最高的成分为β-谷甾醇（β-sitosterol，占比18.64%），其次为乳清酸双(叔丁基二甲基硅基)-叔丁基二甲基硅基酯（12.18%）、10-十八烯酸甲酯（7.90%）以及邻苯二甲酸二异辛酯（6.05%）。三氯甲烷组分中的主要成分为间苯二甲酸二(2-乙基己基)酯（50.82%）与邻苯二甲酸二正辛酯（33.00%）。本研究证实，涩荠甲醇叶片提取物的正己烷与三氯甲烷分级组分中含有强效抗真菌活性成分，可用于尖孢镰刀菌葱专化型的病害防控。