Harnessing the Power of Medicinal Plants as New Antimicrobial Sources: A Systematic Review

Introduction: Medicinal plants, known for their rich bioactive compounds, exhibit broad antimicrobial effects against bacteria, fungi, parasites, and viruses. Due to their diverse therapeutic properties, these plants are now a key focus for researchers exploring novel antimicrobial agents. This comprehensive review was conducted to provide compelling evidence of medicinal plants exhibiting substantial antimicrobial activities. Additionally, the paper delved into the crucial factors guiding the selection of appropriate plants with the potential to serve as new antimicrobial agents. Method: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to select the relevant data, a search was performed using specific keywords; “medicinal plants” OR “herbs” AND “natural products” AND “antimicrobial properties,” across databases like PubMed, Scopus, and Science Direct. The literature search was limited to only “articles” and “journals” wherever possible. Total of 64 studies, including in-vitro and in-vivo, were subjected to Risk of Bias analysis using ToxRTool for data quality assessment. Results: The review collected data on 269 plant species, revealing that 76 plants displayed significant antimicrobial activity, with Asteraceae (30.3%) and Lamiaceae (24.2%) families containing the highest number of potent candidates. Notably, leaves (42.9%) and aerial parts (20.9%) were the predominantly utilized plant components in antimicrobial studies, mainly due to their high concentration of secondary metabolites. Furthermore, organic solvents like methanol and ethanol were effective in extracting active compounds from these plants. Discussion: The widespread use of leaves (42.9%) and aerial parts (20.9%) in antimicrobial evaluations is likely due to their accessibility and rich phytochemical content. These parts are more sustainable to harvest and are often primary sites for the synthesis and accumulation of compounds involved in plant defense, making them valuable for screening purposes. Organic solvents such as methanol and ethanol proved particularly efficient in extracting antimicrobial compounds. Their ability to dissolve a wide array of chemical constituents allows for better recovery of potentially active molecules, thereby enhancing the effectiveness of phytochemical analyses. Conclusion: The review highlights that the antimicrobial efficacy of medicinal plants is significantly influenced by the choice of plant parts, preparation techniques, and the type of solvents used during extraction. These factors play a pivotal role in optimizing the yield and bioactivity of phytochemicals, ultimately enhancing the therapeutic potential of medicinal plants for combating microbial infections.