Mitochondrial Topo I Inhibitors

Mitochondrial Topo I inhibitors represent a diverse assembly of chemicals that target the relaxation activity of supercoiled DNA by topoisomerase I within the mitochondria. Many of these inhibitors, such as Camptothecin and its derivatives like Topotecan and Irinotecan, operate by stabilizing the transient breakage of DNA strands, effectively forming a cleavable complex between the DNA and the enzyme. The stabilization of this complex obstructs the usual DNA repair mechanisms, leading to strand breaks.While Camptothecin-derived inhibitors are widely recognized for their role, other compounds like β-Lapachone and Indenoisoquinolines also offer unique mechanisms of action. For example, β-Lapachone can induce DNA damage via a pathway involving Topo I inhibition, while Indenoisoquinolines, as non-camptothecin inhibitors, bind to the enzyme-DNA complex and block DNA re-ligation. Additionally, natural compounds, ranging from flavonoids like Acacetin and Genistein to marine alkaloids like Lamellarin D, contribute to this category, emphasizing the broad spectrum of structures and origins these inhibitors come from.