Medicinal Herbs as Novel Therapies against Antibiotic-Resistant Bacteria

Abstract

Antibiotic development in the previous century resulted in a decrease in mortality and morbidity associated with infectious diseases, however their indiscriminate and irrational application resulted in the proliferation of resistant microbial populations. Pathogenic bacteria gain intrinsic resistance to antibiotics through a variety of techniques, including alteration of target sites, active efflux of drugs, and enzymatic degradation. This has resulted in an increased interest in medicinal plants, as 25–50% of existing pharmaceuticals are extracted from plants. Due to the diversity of secondary metabolites found in medicinal herbs, crude extracts can serve as an alternative source of resistance modifying agents. These metabolites (alkaloids, tannins, and polyphenols, for example) may have antimicrobial and resistance-modifying properties. Herb extracts can bind to protein domains, modifying or inhibiting protein–protein interactions. This enables herbals to act as potent modulators of host-related cellular processes, including immune response, mitosis, apoptosis, and signal transduction. Thus, they can exert their activity not only by destroying the microorganism but also by interfering with key events in the pathogenic process, reducing the ability of bacteria, fungi, and viruses to develop resistance to botanicals. The present review is intended to encourage research in which the extract's cidal activity is not the only factor considered, but also other mechanisms of action by which plants can fight drug-resistant microbes are investigated.