Humulus lupulus Linn. is a traditional medicinal and edible plant with several biological properties. The aims of this work were: (1) to evaluate the in vitro antifungal activity of H. lupulus ethanolic extract; (2) to study the in vitro and in vivo antifungal activity of isoxanthohumol, an isoprene flavonoid from H. lupulus, against Botrytis cinerea; and (3) to explore the antifungal mechanism of isoxanthohumol on B. cinerea. The present data revealed that the ethanolic extract of H. lupulus exhibited moderate antifungal activity against the five tested phytopathogenic fungi in vitro, and isoxanthohumol showed highly significant antifungal activity against B. cinerea, with an EC₅₀ value of 4.32 µg/mL. Meanwhile, it exhibited moderate to excellent protective and curative efficacies in vivo. The results of morphologic observation, RNA-seq, and physiological indicators revealed that the antifungal mechanism of isoxanthohumol is mainly related to metabolism; it affected the carbohydrate metabolic process, destroyed the tricarboxylic acid (TCA) cycle, and hindered the generation of ATP by inhibiting respiration. Further studies indicated that isoxanthohumol caused membrane lipid peroxidation, thus accelerating the death of B. cinerea. This study demonstrates that isoxanthohumol can be used as a potential botanical fungicide for the management of phytopathogenic fungi.

中文翻译：

---

Humulus lupulus Linn 异黄腐酚的抗真菌机制。

葎草。是一种具有多种生物学特性的传统药用和食用植物。这项工作的目的是：(1) 评价狼疮乙醇提取物的体外抗真菌活性；(2) 研究异黄腐酚（一种来自狼疮的异戊二烯类黄酮）对灰葡萄孢菌的体外和体内抗真菌活性；(3)探索异黄腐酚对灰霉病菌的抗真菌作用机制。目前的数据表明，H. lupulus的乙醇提取物在体外对五种测试的植物病原真菌表现出中等的抗真菌活性，而异黄腐酚对B. cinerea表现出非常显着的抗真菌活性，EC ₅₀值为 4.32 µg/mL。同时，它在体内表现出中等至优异的保护和治疗功效。形态学观察、RNA-seq、生理指标结果表明，异黄腐酚的抗真菌机制主要与代谢有关；它影响碳水化合物代谢过程，破坏三羧酸（TCA）循环，并通过抑制呼吸来阻碍ATP的产生。进一步研究表明，异黄腐酚引起膜脂过氧化，从而加速了灰霉病菌的死亡。该研究表明，异黄腐酚可用作管理植物病原真菌的潜在植物杀菌剂。