Synthesis and structure-activity relationships of hydroxylated and halogenated 2,4-diaryl benzofuro[3,2-b]pyridin-7-ols as selective topoisomerase IIα inhibitors

Discovery, synthesis, and antibacterial activity of novel myrtucommulone analogs as inhibitors of DNA gyrase and topoisomerase IV

Drug-resistant bacterial infections have emerged as a new challenge in anti-infective treatment, posing a significant threat to public health. DNA gyrase and topoisomerase IV (Topo IV) are promising targets for designing new antibiotics. Myrtus communis L. has long been used as a traditional herb for antisepsis and disinfection; however, the underlying mechanism of the antibacterial activity remains unclear. In this study, a class of novel myrtucommulone derivatives was synthesized and evaluated for DNA gyrase and Topo IV inhibitions. Analog 27 was the most potent DNA gyrase and Topo IV inhibitor. In bioactivity assays, molecule 27 exhibited a significant antibacterial effect against methicillin-resistant Staphylococcus aureus (MRSA). Additionally, it exhibited rapid bactericidal properties, low toxicity, and low inducing bacterial resistance. It demonstrated synergistic effects with ofloxacin, amikacin, cefepime, and ceftazidime, which make it a potential candidate for antimicrobial application. This work will facilitate the future development of myrtucommulone-based DNA gyrase and Topo IV inhibitors as novel antimicrobials to combat the increasing prevalence of multidrug-resistant bacteria.

Upgrade of chrysomycin A as a novel topoisomerase II inhibitor to curb KRAS-mutant lung adenocarcinoma progression

A primary strategy employed in cancer therapy is the inhibition of topoisomerase II (Topo II), implicated in cell survival. However, side effects and adverse reactions restrict the utilization of Topo II inhibitors. Thus, investigations focus on the discovery of novel compounds that are capable of inhibiting the Topo II enzyme and feature safer toxicological profiles. Herein, we upgrade an old antibiotic chrysomycin A from Streptomyces sp. 891 as a compelling Topo II enzyme inhibitor. Our results show that chrysomycin A is a new chemical entity. Notably, chrysomycin A targets the DNA-unwinding enzyme Topo II with an efficient binding potency and a significant inhibition of intracellular enzyme levels. Intriguingly, chrysomycin A kills KRAS-mutant lung adenocarcinoma cells and is negligible cytotoxic to normal cells at the cellular level, thus indicating a capability of potential treatment. Furthermore, mechanism studies demonstrate that chrysomycin A inhibits the Topo II enzyme and stimulates the accumulation of reactive oxygen species, thereby inducing DNA damage-mediated cancer cell apoptosis. Importantly, chrysomycin A exhibits excellent control of cancer progression and excellent safety in tumor-bearing models. Our results provide a chemical scaffold for the synthesis of new types of Topo II inhibitors and reveal a novel target for chrysomycin A to meet its further application.

Base-Catalyzed Sequential 1,4-Addition/Intramolecular Cyclization/Aromatization Reaction: Synthesis of Benzofuro[3,2-b]pyridines

An efficient K₂CO₃-catalyzed 1,4-addition/intramolecular cyclization/aromatization reaction of aurone-derived 1-azadienes with trisubstituted allenoates has been developed, giving a series of benzofuro[3,2-b]pyridines in moderate to excellent yields. The reaction proceeded efficiently under an air atmosphere without the use of transition metal catalysts. This protocol provides a concise approach to benzofuro[3,2-b]pyridines.