Resurgence of the interest in plants as sources of medicines and resistance-modifying agents

In the last decades, bacterial resistance to antimicrobials has become a serious threat to clinical and public health. Traditional methods of antibiotic discovery have failed to get new alternatives and solutions to face the fast rhythmus of resistance evolution. Therefore, new strategies to control bacterial infections are highly desirable. The therapeutic value of plant extracts is well-known for centuries. Indeed, medicinal plants always had an important role on the treatment of several illnesses and infections. Plants can produce complex mixtures of structural different compounds. Some of them are being reported to have significant antimicrobial activity against several important clinical pathogens or for their action as synergists or potentiators of other antibacterial agents, by interacting with them or with the pathogens in several ways. This chapter aims to present an overview about the current state of the use of antibiotic coadjuvants and resistance-modifying agents in clinical treatments. Also, the use of plants as promising sources of novel compounds with clinical interest will be highlighted.