Bacterial drug resistance towards natural products

Abstract

The upsurge of antimicrobial resistance is occurring worldwide, endangering the efficacy of antibiotics. Over several decades, bacteria causing common or severe infections have developed resistance to each new antibiotic up for sale. This drives the growing need for identifying alternatives to antibiotics in the prevention and treatment of bacterial infections. One such approach is the utilization of naturally occurring compounds. Specific to antibacterial agents, natural products and their derivatives make up 69% of all U.S. Food and Drug Administration (FDA)-approved drugs. The majority of these come from microbes (97%), with plant products contributing 3% to this group. However, when it comes to the search for new antimicrobials, there is much that an ethnobotanical approach to drug discovery can offer. Conventional curative systems have counted upon traditional herbs that are rich in compounds, such as alkaloids, terpenoids, tannins, steroids, coumarins, and flavonoids, which present a great potential for use, either as antimicrobials or as antibiotic resistance modifiers. Resistance has been reported to almost all antibacterial agents originating from microorganisms and their derivatives. As a result, many researchers have turned to plant-based products, which were long claimed to offer lower bacterial resistance. The bioactive complex composition of the plant extracts interacts with multiple bacterial cellular targets instead of a particular single mode of action, thus inhibiting pathogens from acquiring resistance. This chapter provides an appraisal of bacterial resistance towards natural products, emphasizing plant antibacterials. The major mechanisms of antibacterial resistance and the molecular targets of established antibacterial agents are also discussed.