Studio dell'attività antimicrobica di estratti da piante e altri prodotti naturali

Despite the remarkable advancements in medical research during last century, infectious diseases still remain one of the leading causes of death worldwide, and the emergence of multidrug resistance has made formerly easy-treatable infections severe life threats. This situation urges the discovery of new antimicrobial drugs or resistance-modifying agents as efflux pump inhibitors to control such infections. Plants have long been traditionally used to prevent or cure infectious conditions all over the world, and also in Sardinia region (Italy). For this reason the potential antimicrobial properties of plant extracts ofCamellia sinensisandMyrtus communisand natural products fromDiplodia cupressihave been explored on a collection of different pathogens including typhoidalSalmonella,E. coli,Streptococcus agalactiaeandviridans,Enterococcus faecalisandCandida spp, and influenza virus. Further we tested these extracts in MDR Salmonella Typhi strains to explore the potential inhibitory activity of the efflux pumps whose overexpression rendered antibiotics therapeutically ineffective in MDR strains. The results obtained showed that the extracts of C. sinensis andD. cupressiexhibited bactericidal activity against MDRSalmonella Typhiand a wide range of pathogens Interestingly in MDR S. Typhi the extracts ofD. cupressiandC. sinensisexerted a inhibitory effux pumps effect inducing a reversal of tetracycline resistance. FurthermoreM. communisextract showed high anti-viral activity against influenza virus (H3N2). This finding could be useful in realizing promising antimicrobials for the treatment of typhoid fever caused byS. Typhiand influenza virus.