绒叶泡桐花中除草活性成分的分离与除草活性

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。

Isolation and Bioassay of Herbicidal Active Ingredient fromPaulownia tomentosa

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.