Benzotriazole in Cancer: A Systematic Review on Preclinical Evidence and Structure–Activity Relationship

<b>Background:</b> A benzotriazole is a heterocycle frequently used in medicinal chemistry to obtain potent drug candidates, including anticancer agents. Nonetheless, the available literature lacks a comprehensive review of the in vitro and in vivo studies regarding these derivatives. Thus, our study aims to review the preclinical evidence on benzotriazole derivatives that showed potential as anticancer candidates, focusing on the cytotoxicity, mechanisms of action, structure-activity relationship, and methodological rigor of the included studies. <b>Methods:</b> We searched PubMed, Scopus, and Web of Science and included 41 studies in our analysis following the selection process. Additionally, we assessed the risk of bias using the QUIN tool for in vitro and the SYRCLE tool for in vivo studies in order to assess the methodological rigor of the included studies. <b>Results:</b> The benzotriazole derivatives were classified according to their structure in four classes, namely N-derivatives, C-derivatives, fused derivatives, and organometallic compounds. The in vitro results showed that certain derivatives, such as halogen, alkyl-aryl, or natural-base hybrids, can have superior cytotoxicity compared to parent molecules, exerted through multiple mechanisms, such as apoptosis and cell cycle arrest. Additionally, the in vivo analysis highlighted that benzotriazole derivatives can reduce tumor mass in a dose-dependent manner, with only a slight degree of hepatotoxicity reported in one case. However, histopathological data were generally absent or limited and based on a very limited number of in vivo studies. <b>Conclusions:</b> Overall, benzotriazole derivatives remain promising candidates for cancer treatment. However, limited mechanistic and toxicity data, as well as the moderate risk of bias identified across studies, may limit our assessment. Therefore, future studies should employ more rigorous methodologies and explore the underlying anticancer and toxicity mechanisms to fully assess the therapeutic potential of benzotriazole derivatives.