The natural product piperlonguminine (PL) has been shown to exert potential anticancer activity against several types of cancer via elevation of reactive oxidative species (ROS). However, the application of PL has been limited due to its poor water solubility and moderate activity. To improve PL's potency, we designed and synthesized a series of 17 novel phenylmethylenecyclohexenone derivatives and evaluated their pharmacological properties. Most of them exerted antiproliferative activities against four cancer cell lines with IC₅₀ values lower than PL. Among these, compound 10 e not only showed good water solubility and exerted the most potent antiproliferative activity against HGC27 cells (IC₅₀=0.76 μM), which was 10‐fold lower than PL (IC₅₀=7.53 μM), but also exhibited lower cytotoxicity in human normal gastric epithelial cells GES‐1 compared with HGC27 cells. Mechanistically, compound 10 e inhibited thioredoxin reductase (TrxR) activity, increased ROS levels, and diminished mitochondrial transmembrane potential (MTP) in HGC27 cells. Furthermore, 10 e also induced G₂/M cell‐cycle arrest, and triggered cancer cell apoptosis through the regulation of apoptotic proteins. Finally, 10 e promoted DNA damage in HGC27 cells via the activation of the H2AX(S139ph) and p53 signaling. In conclusion, 10 e, with prominent tumor selectivity and water solubility, could be a promising candidate for the treatment of cancer and, as such, warrants further investigation.

中文翻译：

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新型苯基亚甲基环己烯酮衍生物作为强效 TrxR 抑制剂显示出高抗增殖活性并诱导 ROS、细胞凋亡和 DNA 损伤

天然产物胡椒碱 (PL) 已被证明通过提高活性氧化物质 (ROS) 对几种类型的癌症发挥潜在的抗癌活性。然而，PL由于其水溶性差和活性适中而限制了其应用。为了提高 PL 的效力，我们设计并合成了一系列 17 种新型苯基亚甲基环己烯酮衍生物，并评估了它们的药理特性。它们中的大多数对四种癌细胞系发挥抗增殖活性，IC ₅₀值低于PL。在这些当中，化合物10e中不仅显示出良好的水溶性和所施加的最有效的抗增殖活性的对抗HGC27细胞（IC ₅₀ = 0.76μM），这是10倍PL下（IC ₅₀=7.53 μM)，但与 HGC27 细胞相比，在人正常胃上皮细胞 GES-1 中也表现出较低的细胞毒性。机械地，化合物10e中抑制硫氧还蛋白还原酶（的TrxR）活性，增加的ROS水平，并在HGC27细胞减少线粒体跨膜电位（MTP）。此外，10 e还诱导 G ₂ /M 细胞周期停滞，并通过调节凋亡蛋白引发癌细胞凋亡。最后，10 e通过激活 H2AX(S139ph) 和 p53 信号促进 HGC27 细胞中的 DNA 损伤。总之，10 e具有突出的肿瘤选择性和水溶性，可能是治疗癌症的有希望的候选者，因此值得进一步研究。