Indian Medicinal Plants in Antimicrobial Drug Discovery: Phytochemical Diversity, Structure-Activity Relationships, Advanced Analytical Characterization, and Therapeutic Potential

Abstract

Multidrug-resistant organisms are a major public health concern, as antimicrobial resistance (AMR) has become one of the greatest threats worldwide, prompting researchers to search for new therapeutic agents that can inhibit multidrug-resistant organisms. Indian medicinal plants are a treasure trove of structurally diverse bioactive phytochemicals such as phenolic compounds, flavonoids, alkaloids, terpenoids, coumarins, sulfur-containing compounds, tannins and glycosides, many of which have potent antimicrobial properties. This review comprehensively summarizes recent studies on the phytochemical diversity of Indian medicinal plants, highlighting their structure–activity relationships (SAR), molecular mechanisms of antimicrobial action, and applications against clinically significant bacterial and fungal pathogens. Advanced analytical methods such as GC-MS, LC-MS, UPLC-QTOF-MS, FTIR and one- and two-dimensional NMR spectroscopy have contributed to the accurate phytochemical characterization and quality assessment highlighted by the review. In addition, it covers various antimicrobial mechanisms, such as disruption of microbial cell walls and cell membranes, inhibition of DNA replication and protein synthesis, inhibition of efflux pumps, induction of oxidative stress, and biofilm suppression. Growing evidence supports the activity of natural products and nano-formulations against multidrug-resistant organisms such as methicillin-resistant Staphylococcus aureus (MRSA), extended-spectrum β-lactamase (ESBL) producers, Acinetobacter baumannii, Pseudomonas aeruginosa, and Candida auris. These encouraging results, however, come with many hurdles, such as phytochemical standardization, bioavailability, toxicity assessment, regulatory clearance, and industrialization. Prospects include metabolomics, artificial intelligence, nanotechnology, green extraction technologies, and translational research, all of which can help speed the development of safe and effective antimicrobial therapeutics from plants. In conclusion, Indian medicinal plants are a valuable and sustainable resource for developing antimicrobial agents of the future, holding significant potential to address the escalating issue of antimicrobial resistance.