RESUMO
New efficient antifungal agents are urgently needed to treat drug-resistant fungal infections. Here, we designed and synthesized a series of cationic xanthone amphiphilics as antifungal agents from natural α-mangostin to combat fungal resistance. The attachment of cationic residues on the xanthone scaffold of α-mangostin resulted in interesting antifungal agents with a novel mode of action. Two lead compounds (1 and 2) showed potent antifungal activity against a wide range of fungal pathogens, including drug-resistant Candida albicans, Aspergillus, and Fusarium strains and low cytotoxicity and hemolytic activity against mammalian cells. Both compounds can kill fungus rapidly by directly disrupting fungal cell membranes and avoid developing drug resistance. Additionally, compound 1 exhibited potent in vivo antifungal activity in the murine model of fungal keratitis. To our knowledge, membrane-targeting xanthone-based antifungals have not been reported previously. These results demonstrated that compounds 1 and 2 may be promising candidates for treating drug-resistant fungal infections.
Assuntos
Antifúngicos/química , Antifúngicos/farmacologia , Farmacorresistência Fúngica/efeitos dos fármacos , Xantonas/química , Animais , Antifúngicos/síntese química , Aspergillus/efeitos dos fármacos , Candida/efeitos dos fármacos , Linhagem Celular , Avaliação Pré-Clínica de Medicamentos/métodos , Fibroblastos/efeitos dos fármacos , Fusarium/efeitos dos fármacos , Hemolíticos/química , Hemolíticos/farmacologia , Humanos , Concentração Inibidora 50 , Ceratite/tratamento farmacológico , Ceratite/microbiologia , Camundongos Endogâmicos C57BL , Testes de Sensibilidade Microbiana , Relação Estrutura-AtividadeRESUMO
A new series of semisynthetic flavone-based small molecules mimicking antimicrobial peptides has been designed from natural icaritin to combat drug-resistant Gram-positive bacterial infections. Compound 6 containing two arginine residues exhibited excellent antibacterial activity against Gram-positive bacteria, including MRSA, and very low toxicity to mammalian cells, resulting in a high selectivity of more than 511, comparable to that of several membrane-active antibiotics in clinical trials. Our data show for the first time that icaritin derivatives effectively kill bacteria. Meanwhile, this is the first study deploying a biomimicking strategy to design potent flavone-based membrane targeting antimicrobials. 6 showed rapid bactericidal activity by disrupting the bacterial membrane and can circumvent the development of bacterial resistance. Importantly, 6 was highly efficacious in a mouse model of corneal infection caused by MRSA and Staphylococcus aureus.
