Quinoline (QN) derivatives are often used for the prophylaxis and treatment of malaria. Chloroquine (CQ), a protonated, weakly basic drug, exerts its antimalarial effect mainly by increasing pH and accumulating in the food vacuole of the parasites. Repurposing CQ is an emerging strategy for new indications. Given the inhibition of autophagy and its immunomodulatory action, CQ shows positive efficacy against cancer and viral diseases, including Coronavirus 2019 (COVID-19). Here, we review the underlying mechanisms behind the antimalarial, anticancer and antiviral effects of CQ. We also discuss the clinical evidence for the use of CQ and hydroxychloroquine (HCQ) against COVID-19.

喹啉（QN）衍生物通常用于预防和治疗疟疾。氯喹（CQ）是一种质子化的弱碱性药物，主要通过提高pH值并在寄生虫的食物泡中积聚来发挥抗疟作用。重新利用 CQ 是针对新适应症的一项新兴策略。鉴于自噬的抑制及其免疫调节作用，CQ 对癌症和病毒性疾病（包括 2019 年冠状病毒 (COVID-19)）表现出积极的功效。在这里，我们回顾了 CQ 抗疟疾、抗癌和抗病毒作用背后的潜在机制。我们还讨论了使用 CQ 和羟氯喹 (HCQ) 对抗 COVID-19 的临床证据。