The use of biopesticides has expanded rapidly in recent years; however, their use in weed control is less advanced. Herein, we describe the development of a weed control agent by screening 208 plant extracts (104 species) for their plant growth-inhibition activities, which resulted in 142 active samples (from 89 plant species). Verbascoside, isolated from the shoots of Verbena incompta, was identified as a growth inhibitor against rice root (EC50, 1.75 m m), and its root growth-inhibition activity was also confirmed in radish, tomato, and Lotus japonicus. Verbascoside is composed of hydroxytyrosol (EC50,12.51 m m) and caffeic acid (EC50, 4.08 m m), 2 poorly water-soluble phenolic components with weak growth-inhibition activities, and 2 sugars, which are more soluble but inactive. The plant apparently developed a more active and highly soluble compound by condensing these 4 components. We conclude that a biopesticide containing verbascoside may be useful for weed-control purposes.

中文翻译：

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Verbena incompta 中的 Verbascoside 是一种植物根系生长抑制剂。

近年来，生物农药的使用迅速扩大；然而，它们在杂草控制中的应用并不先进。在此，我们通过筛选 208 种植物提取物（104 种）的植物生长抑制活性来描述杂草控制剂的开发，这产生了 142 种活性样品（来自 89 种植物）。从马鞭草的枝条中分离出的马鞭草苷被鉴定为水稻根的生长抑制剂 (EC50, 1.75 m m)，其根生长抑制活性也在萝卜、番茄和莲藕中得到证实。Verbascoside 由羟基酪醇 (EC50,12.51 m m) 和咖啡酸 (EC50, 4.08 m m)、2 种具有弱生长抑制活性的难溶于水的酚类成分和 2 种糖类组成，后者更易溶解但无活性。该植物通过浓缩这 4 种成分，显然开发出一种活性更高、溶解度更高的化合物。我们得出结论，含有毛蕊花苷的生物农药可能对杂草控制有用。