Phytomedicine Plus (May 2022)
“Endophytes: an unexplored treasure to combat Multidrug resistance”
Abstract
Background: Multidrug resistance (MDR) in microorganisms has culminated in major health crisis globally and accounts for approximately 700,000 morbidities every year. Recently, there has been a surge towards re-discovering medieval treatment strategies to develop novel therapeutic approaches against MDR pathogens. Exploring the potential of plant based compounds or isolates from plant-associated microbes for the treatment of these infections is being tried. One unexplored domain in this context is endophytes. Endophytes are endosymbiotic microorganisms residing in the inner plant tissues and promoting plant development in various ways. They are known to contribute to the medicinal properties of plants with ethnobotanical histories, produce potent hydrolytic enzymes which prevent host invasion by pathogens, insects, or nematodes, and stimulate plant's defense system. In some cases, secondary metabolites produced by endophytes are similar to that of the host plant, making them an equally efficient candidate for drug development. Thus, these secondary metabolites might hold immense unexplored potential to treat MDR infections in humans and could manifest as an asset. Hypothesis: Despite the advances in utilization of endophytes in different domains, we lack a complete understanding of their potential as anti-microbial agents and their mode of action against MDR pathogens. This limits the development and utilization of endophytes as potential drug candidates. Thus, this review highlights the current global scenario of MDR and aims to provide a detailed analysis of secondary metabolites from endophytes, especially from those growing on medicinal plants for their potential antimicrobial activity. Furthermore, the literature has been thoroughly reviewed to elucidate the potential mechanism of action of endophytes, providing a foundation for future research and in-vivo studies. Methods: A systematic online search was conducted until November 2021 through four scientific databases (PubMed, Google Scholar, Scopus, and PubChem). The articles evaluating the bioactivities of endophytes present on medicinal plants against multidrug resistant microorganisms were considered for the review and the period of study was delimited to literature reported between 2010 to 2021. Results: The first literature search resulted in 72,400 articles. Further, the search was narrowed down based on the activity of endophytes only against MDR organisms and on the basis of inclusion criteria, yielding 22,250 articles. Out of these, 10,720 articles met the inclusion criteria. Approximately 350 articles were selected for thorough literature review and 100 articles with highest cite score and relevant information were included in this review. Our study explored the hidden potential of endophytes as antimicrobial agents and found several candidates that could be utilized in treatment of MDR infections in humans. Conclusion: High availability and low maintenance of endophytes, along with their antimicrobial potential makes them highly applicative pharmaceutical candidates towards the concerns of the “post-antibiotic era” that the humans have approached.
