绒叶泡桐花中除草活性成分的分离与除草活性
Isolation and Bioassay of Herbicidal Active Ingredient fromPaulownia tomentosa
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摘要: 采用活性追踪和柱层析技术,以对杂草反枝苋、生菜、黄瓜种子胚根生长的抑制作用为指标,对泡桐花中除草活性成分进行了提取、分离和鉴定。绒叶泡桐Paulownia tomentosa花乙醇提取物依次用石油醚、乙酸乙酯、正丁醇和水萃取后进行活性测定,结果表明,石油醚萃取物在浓度为 0.5 mg/mL 时,对反枝苋、生菜和黄瓜种子胚根生长的抑制率分别为76.30%、56.17%和23.36%; 乙酸乙酯萃取物在浓度为0.5 mg/mL时,对反枝苋、生菜和黄瓜种子胚根生长的抑制率分别为99.89%、63.53%和32.74%。通过对乙酸乙酯萃取物进行硅胶柱层析分离,得到一种活性较高的化合物,经鉴定其为对乙氧基苯甲醛,其抑制反枝苋种子胚根生长的EC50值为55.20 μg/mL。对乙氧基苯甲醛是首次从绒叶泡桐中分离鉴定的化合物,也是首次将其用于除草活性研究。Abstract: Herbicidal active ingredient extracted,isolated and identified from Paulownia tomentosa (Thund)Steud against Amaranthus retroflexus L.,Lactuca sative var. capitata L. and Cucumis sativus L. were tested by bioassay-guided separation. The extracts from P.tomentosa flower with ethanol were extracted with petroleum ether,ethyl acetate and n-butanol.The inhibition rate of the ethyl acetate extract to growth of the 3 kinds of plant radicel were 99.89%,63.53% and 32.74% respectively at 0.5 mg/mL concentration,and that of petroleum ether were 76.30%,56.17% and 23.36%.One compound had been obtained with silica gel column chromatography from ethyl acetate extraction,and it was authenticated as p-ethoxybenzaldehyde.The inhibitory EC50 of this compound against A.retroflexus radical growth was 55.20 μg/mL.p-Ethoxybenzaldehyde was the first reported from Paulownia tomentosa with herbicidal activity.
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