Selective clearance of senescent cells (SCs) has emerged as a potential therapeutic approach for age-related diseases, as well as chemotherapy- and radiotherapy-induced adverse effects. Through a cell-based phenotypic screening approach, we recently identified piperlongumine (PL), a dietary natural product, as a novel senolytic agent, referring to small molecules that can selectively kill SCs over normal or non-senescent cells. In an effort to establish the structure-senolytic activity relationships of PL analogues, we performed a series of structural modifications on the trimethoxyphenyl and the α,β-unsaturated δ-valerolactam rings of PL. We show that modifications on the trimethoxyphenyl ring are well tolerated, while the Michael acceptor on the lactam ring is critical for the senolytic activity. Replacing the endocyclic C2–C3 olefin with an exocyclic methylene at C2 render PL analogues 47–49 with increased senolytic activity. These α-methylene containing analogues are also more potent than PL in inducing ROS production in WI-38 SCs. Similar to PL, 47–49 reduce the protein levels of oxidation resistance 1 (OXR1), an important oxidative stress response protein that regulates the expression of a variety of antioxidant enzymes, in cells. This study represents a useful starting point toward the discovery of senolytic agents for therapeutic uses.

选择性清除衰老细胞（SCs）已成为治疗与年龄有关的疾病以及化学疗法和放射疗法引起的不良反应的潜在方法。通过基于细胞的表型筛选方法，我们最近确定了膳食中的天然产物哌隆定（PL）作为一种新型的抗衰老剂，是指可以选择性杀灭正常细胞或非衰老细胞的SC的小分子。为了建立PL类似物的结构-衰老活性关系，我们对PL的三甲氧基苯基和α，β-不饱和δ-戊内酰胺环进行了一系列结构修饰。我们表明三甲氧基苯基环上的修饰是很好的耐受性，而内酰胺环上的迈克尔受体对于senolytic活动至关重要。47 - 49具有增加的senolytic活性。这些含α-亚甲基的类似物在诱导WI-38 SC中产生ROS方面也比PL更有效。与PL相似，47 – 49降低了抗氧化蛋白1（OXR1）的蛋白水平，OXR1是一种重要的氧化应激反应蛋白，可调节细胞中多种抗氧化酶的表达。这项研究为发现用于治疗用途的镇静剂提供了有用的起点。