Back to Nature: Medicinal Plants as Promising Sources for Antibacterial Drugs in the Post-Antibiotic Era

Abstract

Undoubtedly, the advent of antibiotics in the 19th century had a substantial impact, increasing human life expectancy. However, a multitude of scientific investigations now indicate that we are currently experiencing a phase known as the post-antibiotic era. There is a genuine concern that we might regress to a time before antibiotics and confront widespread outbreaks of severe epidemic diseases, particularly those caused by bacterial infections. These investigations have demonstrated that epidemics thrive under environmental stressors such as climate change, the depletion of natural resources, and detrimental human activities such as wars, conflicts, antibiotic overuse, and pollution. Moreover, bacteria possess a remarkable ability to adapt and mutate. Unfortunately, the current development of antibiotics is insufficient, and the future appears grim unless we abandon our current approach of generating synthetic antibiotics that rapidly lose their effectiveness against multidrug-resistant bacteria. Despite their vital role in modern medicine, medicinal plants have served as the primary source of curative drugs since ancient times. Numerous scientific reports published over the past three decades suggest that medicinal plants could serve as a promising alternative to ineffective antibiotics in combating infectious diseases. Over the past few years, phenolic compounds, alkaloids, saponins, and terpenoids have exhibited noteworthy antibacterial potential, primarily through membrane-disruption mechanisms, protein binding, interference with intermediary metabolism, anti-quorum sensing, and anti-biofilm activity. However, to optimize their utilization as effective antibacterial drugs, further advancements in omics technologies and network pharmacology will be required in order to identify optimal combinations among these compounds or in conjunction with antibiotics.

Keywords: antibacterial activity; antibiotic-resistant; infections; mechanism of action; phytochemicals; synthetic.

Figure 1

A timeline of epidemics from the early modern period onwards caused by bacteria prior to the discovery of antibiotics (* during the Spanish flu pandemic, one or two of the following species were responsible for the majority of fatal pneumonia: Streptococcus pneumoniae, Streptococcus pyogenes, and/or Staphylococcus aureus [19]).

Figure 2

The emergence of antibiotics and the development of resistance to them (1935–2010) [46,47].

Figure 3

Major bacterial resistance mechanisms against antibiotics.

Figure 4

Significant human behaviors that have an impact on the spread of antibiotic-resistant bacteria.

Figure 5

Growing global interest in the antibacterial properties of medicinal plants through the noticeable increase in the number of published reports over the past decade.

Figure 6

Possible antibacterial modes of action of antibacterial medicinal plants.