RESUMEN
The development of new antibiotics continues to pose challenges, particularly considering the growing threat of multidrug-resistant Staphylococcus aureus. Structurally diverse natural products provide a promising source of antibiotics. Herein, we outline a concise approach for the collective asymmetric total synthesis of polycyclic xanthene myrtucommulone D and five related congeners. The strategy involves rapid assembly of the challenging benzopyrano[2,3-a]xanthene core, highly diastereoselective establishment of three contiguous stereocenters through a retro-hemiketalization/double Michael cascade reaction, and a Mitsunobu-mediated chiral resolution approach with high optical purity and broad substrate scope. Quantum mechanical calculations provide insight into stereoselective construction mechanism of the three contiguous stereocenters. Additionally, this work leads to the discovery of an antibacterial agent against both drug-sensitive and drug-resistant S. aureus. This compound operates through a unique mechanism that promotes bacterial autolysis by activating the two-component sensory histidine kinase WalK. Our research holds potential for future antibacterial drug development.
Asunto(s)
Antibacterianos , Staphylococcus aureus Resistente a Meticilina , Xantenos , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Antibacterianos/farmacología , Antibacterianos/síntesis química , Antibacterianos/química , Xantenos/síntesis química , Xantenos/farmacología , Xantenos/química , Pruebas de Sensibilidad Microbiana , Estereoisomerismo , Compuestos Policíclicos/síntesis química , Compuestos Policíclicos/farmacología , Compuestos Policíclicos/química , Descubrimiento de Drogas , Estructura MolecularRESUMEN
Quorum sensing (QS) is considered an appealing target for interference with bacterial infections. ß-Adrenergic blockers are promising anti-QS agents but do not have antibacterial activity. We assessed the potential ability of adrenergic receptor inhibitors to enhance the antibacterial activity of polymyxin B (PB) against Klebsiella pneumoniae and determined that dronedarone has the most potent activity both in vitro and in vivo. We found that dronedarone increases the thermal stability of LuxS, decreases the production of AI-2, and affects the biofilm formation of K. pneumoniae. We also identified the direct binding of dronedarone to LuxS. However, the mechanism by which dronedarone enhances the antibacterial activity of PB has not been elucidated and is worthy of further exploration. Our study provides a basis for the future development of drug combination regimens.
