To explore candidate fungicides from plant secondary metabolites, 16 novel obovatol-type phenazine derivatives were semi-synthesized from obovatol isolated from the leaves of Magnolia obovata Thunb. The antifungal activity of synthesized compounds was investigated in vitro against four phytopathogenic fungi using the spore germination method. The bioassay results showed that eight derivatives ( 8b , 8g , 8h – k , 8i′ , and 8k′ ) exhibited better antifungal activity against Fusarium solani than two positive controls, especially compounds 8b (IC 50 = 64.61 μg mL −1 ) and 8i′ (IC 50 = 79.97 μg mL −1 ) showed pronounced inhibition of spore germination activity against F. solani . They could be used as lead compounds for further structural optimization. Additionally, the preliminary structure-activity relationships (SARs) illustrated that the introduction of a benzene ring monosubstituted with electron-withdrawing groups into the obovatol scaffold could lead to potentially antifungal compounds.

中文翻译：

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发现新型的基于卵磷脂的吩嗪类似物作为潜在的抗真菌剂：合成和体外生物学评估。

为了探索植物次生代谢物的候选杀真菌剂，从木兰叶木兰叶中分离出的奥波托尔半合成了16种新的奥波托尔型吩嗪衍生物。使用孢子萌发方法，体外研究了合成化合物对四种植物病原真菌的抗真菌活性。生物测定结果表明，八种衍生物（8b，8g，8h – k，8i'和8k'）对腐烂镰刀菌的抗真菌活性优于两个阳性对照，尤其是化合物8b（IC 50 = 64.61μgmL -1）和8i '（IC 50 = 79.97μgmL -1）显示出明显的抑制茄子孢子萌发的孢子萌发活性。它们可用作进一步进行结构优化的先导化合物。此外，