Turmeric (Curcuma spp.) has numerous biological activities, including anticancer, antibacterial, antifungal and insecticidal properties. Here, we evaluated the plant growth‐inhibitory activities of two cultivars of Curcuma longa (C. longa; Ryudai gold and Okinawa ukon) against radish, cress, lettuce and Bidens pilosa (B. pilosa). The methanol extracts of both turmeric varieties inhibited the seed germination and seedling growth of all the tested plants. Ryudai gold had a significantly higher inhibitory effect on the seed germination and root and shoot growth of the plants than Okinawa ukon. Therefore, Ryudai gold was chosen for the isolation of plant growth‐inhibitory compounds using a silica gel column and high‐performance liquid chromatography. The structural identification of the compounds was carried out using ¹H NMR, ¹³C NMR and liquid chromatography–tandem mass spectrometry. The growth inhibitors were identified as four curcuminoids; dihydrobisdemethoxycurcumin (1), bisdemethoxycurcumin (2), demethoxycurcumin (3) and curcumin (4). The IC₅₀ of the curcuminoids against the root and shoot growth of B. pilosa ranged from 8.7 ± 1.7 to 12.9 ± 1.8 and from 15.5 ± 1.8 to 38.9 ± 2.8 μmol L⁻¹, respectively. Compound 1 showed the lowest IC₅₀ against the root and shoot growth of B. pilosa. These results suggested that Ryudai gold has a potential growth‐inhibitory effect against B. pilosa.

中文翻译：

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姜黄中的植物生长抑制剂及其对Bidens pilosa的影响

姜黄（姜黄属）具有许多生物活性，包括抗癌，抗菌，抗真菌和杀虫特性。在这里，我们评估了两个姜黄（C. longa）品种（C. longa； Ryudai gold和Okinawa ukon）对萝卜，水芹，生菜和Bidens pilosa（B。pilosa）的植物生长抑制活性。）。两种姜黄品种的甲醇提取物均能抑制所有测试植物的种子发芽和幼苗生长。与冲绳ukon相比，Ryudai gold对植物的种子发芽以及根和芽生长具有显着更高的抑制作用。因此，使用硅胶色谱柱和高效液相色谱法选择了龙带金用于分离植物生长抑制化合物。使用¹ H NMR，¹³ C NMR和液相色谱-串联质谱法对化合物进行结构鉴定。生长抑制剂被确定为四种姜黄素；二氢双去甲氧基姜黄素（1），双去甲氧基姜黄素（2），脱甲氧基姜黄素（3）和姜黄素（4）。姜黄素对毛发芽孢杆菌根和芽生长的IC ₅₀范围分别为8.7±1.7至12.9±1.8和15.5±1.8至38.9±2.8μmolL ^-1。化合物1对B. pilosa根和芽生长的IC ₅₀最低。这些结果表明，Ryudai黄金对B. pilosa具有潜在的生长抑制作用。