Contribution of phenolic acids and dimethyl sulfone to the allelopathic effect of invasive Tridax procumbens

ABSTRACT Tridax procumbens is an invasive weed with a strong allelopathic activity. In this study, the contribution of phenolic acids and dimethyl sulfone to the allelopathic effect of T. procumbens was evaluated against Raphanus sativus. Phenolic acids (benzoic, ellagic and ferulic), vanillin and dimethyl sulfone were identified and quantified from the strongest fraction of T. procumbens, in an allelopathic assay by high performance liquid chromatography and gas chromatography - mass spectrometry. The contribution of phenolic acids and dimethyl sulfone to the allelopathic effect of T. procumbens, expressed as a total activity, was evaluated by comparing the IC50 value to the concentration of each allelochemical, in a completely randomized design. The benzoic acid presented the strongest inhibitory effect (115 mg kg-1) and the highest contribution (0.483) to the allelopathic effect of T. procumbens, followed by vanillin, dimethyl sulfone and ferulic acid.摘要：羽芒菊（Tridax procumbens）是一种具有较强化感活性的入侵性杂草。本研究以萝卜（Raphanus sativus）为受试生物，评估了酚酸类物质与二甲基砜对羽芒菊化感效应的贡献。通过高效液相色谱法（high performance liquid chromatography）与气相色谱-质谱联用法（gas chromatography-mass spectrometry）开展化感试验，从羽芒菊活性最强的组分中鉴定并定量了酚酸类物质（苯甲酸、鞣花酸与阿魏酸）、香草醛以及二甲基砜。本研究采用完全随机设计，以总活性为表征指标，通过将半最大抑制浓度（IC50）与各化感物质的浓度进行对比，评估了酚酸类物质与二甲基砜对羽芒菊化感效应的贡献。其中，苯甲酸对羽芒菊化感效应的抑制活性最强（115 mg·kg⁻¹），贡献度最高（0.483），其后依次为香草醛、二甲基砜与阿魏酸。