Co-culture of adventitious roots (ARs) of Echinacea purpurea (L.) Moench and E. pallida is a novel method for the production of Echinacea bioactive compounds. In the co-culture system, implementation of an elicitation strategy can likely promote bioactive compound accumulation in ARs. Therefore, in this work, methyl jasmonate (MeJA) was tested as an elicitor to treat 30-d-old bioreactor cultured ARs and the effect of MeJA concentrations on metabolite accumulation to select an optimal concentration of this elicitor. Furthermore, the antioxidant enzyme activities of ARs were also determined for understanding the mechanism of MeJA elicitation. Results showed that the 25 μM MeJA treatment increased metabolite accumulation in ARs with maximum production of phenolics (728.2 mg L⁻¹), flavonoids (622.2 mg L⁻¹), and caffeic acid derivatives (255.3 mg L⁻¹ cichoric acid and 143.9 mg L⁻¹ echinacoside); however, the highest polysaccharide production (approximately 440 mg L⁻¹) was determined at 50 to 200 μM MeJA. The activities of antioxidant enzymes (superoxide dismutase, peroxidase, ascorbate peroxidase, and catalase) reached maximum levels with 25 μM MeJA, demonstrating a close relationship between antioxidant enzymes and secondary metabolite synthesis of co-cultured Echinacea ARs. In addition, the bioactive compound content in MeJA-treated ARs was compared with that in natural plant roots. The result indicated that the contents of phenolics, flavonoids, and caffeic acid derivatives (cichoric acid and echinocoside) were higher in the co-cultured ARs than in plant roots of E. purpurea and E. palida.

紫锥菊(L.) Moench 和E. pallida的不定根 (ARs) 共培养是一种生产紫锥菊的新方法生物活性化合物。在共培养系统中，实施诱导策略可能会促进 AR 中生物活性化合物的积累。因此，在这项工作中，测试茉莉酸甲酯 (MeJA) 作为诱导剂来处理 30 天前的生物反应器培养的 AR，以及 MeJA 浓度对代谢物积累的影响，以选择该诱导剂的最佳浓度。此外，还测定了 AR 的抗氧化酶活性，以了解 MeJA 诱导的机制。结果表明，25 μM MeJA 处理增加了 AR 中代谢物的积累，并产生了最大的酚类物质（728.2 mg L ^-1）、类黄酮（622.2 mg L ^-1）和咖啡酸衍生物（255.3 mg L ^-1菊苣酸和 143.9 mg L ^-1松果菊苷）；然而，最高的多糖产量（大约 440 mg L ^-1）是在 50 到 200 μM MeJA 下测定的。抗氧化酶（超氧化物歧化酶、过氧化物酶、抗坏血酸过氧化物酶和过氧化氢酶）的活性在 25 μM MeJA 时达到最高水平，表明抗氧化酶与共培养紫锥菊AR 的次级代谢物合成之间存在密切关系。此外，将 MeJA 处理的 AR 中的生物活性化合物含量与天然植物根中的生物活性化合物含量进行了比较。结果表明，共培养ARs中酚类、黄酮类和咖啡酸衍生物（菊苣酸和棘豆苷）的含量高于E. purpurea和E. palida的植物根。