Exploring Endophytic Microbiomes of <i>Solanum nigrum</i> and <i>Aristolochia indica</i>: A Green Approach to Sustainable Drug Discovery

The accelerating demand for eco-friendly, sustainable therapeutic alternatives has highlighted the potential of plant-associated microbiomes as a promising resource for novel drug discovery. Among these, endophytic microorganisms those that reside asymptomatically within plant tissues—are gaining prominence due to their ability to synthesize a diverse range of bioactive metabolites analogous to their host plants. This study explores the endophytic microbiomes of two underutilized yet pharmacologically rich medicinal plants, <i>Solanum nigrum</i> (Black Nightshade) and <i>Aristolochia indica</i> (Indian Birthwort), collected from the semi-evergreen ecosystem of Sanjay Gandhi National Park (SGNP), Borivali, Maharashtra, India. Both species, despite their rich ethnomedicinal background, remain underexplored in terms of their microbial associations. <i>S. nigrum</i> is known for its hepatoprotective, anticancer, and anti-inflammatory effects, while <i>A. indica</i> exhibits antimicrobial and antimalarial properties. Endophytes were isolated from surface-sterilized root, stem, and leaf tissues using standard culturing techniques. A total of 46 morphologically distinct bacterial and fungal endophytes were recovered and subjected to molecular identification via 16S rRNA and ITS sequencing, respectively. Functional screening revealed several promising strains with potent antibacterial activity against <i>Staphylococcus aureus</i> and <i>Escherichia coli</i>, antioxidant potential via DPPH radical scavenging assay, and cytotoxic effects against HeLa cell lines. Notably, strains of <i>Bacillus</i>, <i>Streptomyces</i>, and <i>Fusarium</i> showed strong metabolic profiles. Further, diversity indices (Shannon-Weaver, Simpson) indicated higher endophytic richness in <i>A. indica</i> roots compared to aerial parts. This investigation underscores the symbiotic microbial wealth harbored within neglected medicinal flora and their potential application in drug development pipelines. By adopting a green bioprospecting approach through plant-endophyte synergy, this study opens up a sustainable avenue for exploring bioactive compounds while conserving biodiversity. The findings lay the groundwork for future metagenomic and metabolomic studies aimed at tapping endophytic biosynthetic pathways.