Medicinal Plants: A Tool to Overcome Antibiotic Resistance ?

Bacterial antibiotic resistance has become a serious problem of public health that concerns almost all antibacterial agents and that manifests in all fields of their application. Consequently, there is an increasing interest in the search for new compounds which can act by a direct antimicrobial effect or by inhibiting resistance mechanisms of microorganisms of medical importance. Medicinal plants nowadays remain a valuable source for this kind of compounds. The direct antimicrobial properties of a number of natural compounds have indeed been reported; such compounds act by many mechanisms, including: (i) complexation with macromolecules such as proteins and polysaccharides, thus inhibiting their functions (polyphenols); (ii) disruption of microbial membranes (lipophilic flavonoids, terpenoids, plant defensins); and (iii) inhibition of adhesion of microbial proteins to host polysaccharide receptors (polypeptides). Medicinal plants also provide compounds which are not necessarily effective against microorganisms, but which enhance or restore the activity of antibiotics by inhibiting resistance mechanisms. These compounds belong to several phytochemical groups and act as inhibitors of efflux pumps (flavonoids, terpenoids, alkaloids); inhibitors of PBP 2a (quinones, terpenoids), enhancers of the permeability of bacterial membrane (terpenoids) and beta-lactamases inhibitors (alkyls gallates). © 2009 Nova Science Publishers, Inc. All rights reserved.SCOPUS: ch.b