The growing number of infectious diseases around the world threatens the effective response of antibiotics, contributing to the increase in antibiotic resistance seen as a global health problem. Currently, one of the main challenges in antimicrobial drug discovery is the search for new compounds that not only exhibit antimicrobial activity, but can also potentiate the antimicrobial activity and revert antibiotics’ resistance, through the interference with several mechanisms, including the inhibition of efflux pumps (EPs) and biofilm formation. Inspired by macroalgae brominated bromophenol BDDE with antimicrobial activity, a series of 18 chalcone derivatives, including seven chalcones (9–15), six dihydrochalcones (16–18, and 22–24) and five diarylpropanes (19–21, and 25 and 26), was prepared and evaluated for its antimicrobial activity and potential to fight antibiotic resistance. Among them, chalcones 13 and 14 showed promising antifungal activity against the dermatophyte clinical strain of Trichophyton rubrum, and all compounds reversed the resistance to vancomycin in Enterococcus faecalis B3/101, with 9, 14, and 24 able to cause a four-fold decrease in the MIC of vancomycin against this strain. Compounds 17–24 displayed inhibition of EPs and the formation of biofilm by S. aureus 272123, suggesting that these compounds are inhibiting the EPs responsible for the extrusion of molecules involved in biofilm-related mechanisms. Interestingly, compounds 17–24 did not show cytotoxicity in mouse embryonic fibroblast cell lines (NIH/3T3). Overall, the results obtained suggest the potential of dihydrochalcones 16–18 and 22–24, and diarylpropanes 19–21, 25 and 26, as hits for bacterial EPs inhibition, as they are effective in the inhibition of EPs, but present other features that are important in this matter, such as the lack of antibacterial activity and cytotoxicity.
世界范围内不断增加的传染病数量威胁着抗生素的有效应对,导致抗生素耐药性的增加,成为全球性的健康问题。目前,抗微生物药物发现面临的主要挑战之一是寻找新的化合物,这些化合物不仅具有抗微生物活性,而且还可以通过干预多种机制,包括抑制外输泵(EPs)和生物膜形成,增强抗微生物活性并逆转抗生素耐药性。受具有抗微生物活性的大型藻类溴化溴酚BDDE的启发,制备了一系列18个查尔酮衍生物,包括七个查尔酮(9-15),六个二氢查尔酮(16-18和22-24)和五个二芳基丙烷(19-21和25和26),并评估了它们的抗微生物活性和对抗抗生素耐药性的潜力。其中,查尔酮13和14显示出对毛癣临床菌株Trichophyton rubrum的有前途的抗真菌活性,所有化合物都逆转了Enterococcus faecalis B3 / 101对万古霉素的耐药性,其中9、14和24能够导致万古霉素对该菌株的MIC降低四倍。化合物17-24显示出对S. aureus 272123的EPs和生物膜形成的抑制作用,表明这些化合物抑制了负责生物膜相关机制中所涉分子外输的EPs。有趣的是,化合物17-24在小鼠胚胎成纤维细胞系(NIH / 3T3)中没有细胞毒性。总的来说,所得结果表明,二氢查尔酮16-18和22-24以及二芳基丙烷19-21、25和26具有抑制细菌EPs的潜力,因为它们在抑制EPs方面有效,但在这方面还具有其他重要特征,例如缺乏抗菌活性和细胞毒性。