Volatiles from Subtropical Convolvulaceae That Interfere with Bacterial Cell-to-Cell Communication as Potential Antipathogenic Drugs

Abstract

Increasing chronic bacterial infections create an urgent need for new antimicrobial agents or strategies for their control. Targeting virulence is one of the alternative approaches to find new medicines to treat persistent infections due to bacteria with biofilm-phenotype which are more resistant to antibiotics than their planktonic counterparts having an extreme capacity for evading the host defences. A bioguided study of sixteen extracts from flowers and leaves of four subtropical Convolvulaceae species provided evidence of the occurrence of antipathogenic natural products active against Gram positive and negative bacteria. Particularly, volatile metabolites fromMerremia dissectacreeper, a food and medicinal plant, were able to interfere with thePseudomonas aeruginosaquorum sensing system by a strong decrease ofN-acyl homoserine lactone (AHL) biosynthesis (63–75%), which attenuated the virulence factor expression like biofilm (55%) and elastase activity (up to 27%), key factors that enable the colonization and dissemination of the infection in the host. Control of theP. aeruginosabiofilm and the QS process by phytochemicals, such as (+) spathulenol, isolated from a bioactive extract ofM. dissectaleaves would be a good strategy for the development of new and effective antipathogenic drugs.