Authors: Gayatri Pandram
Abstract: Endophytic fungi are ubiquitous microorganisms that asymptomatically colonize the internal tissues of plants, representing an untapped reservoir of novel, biologically active secondary metabolites. This study investigates the endophytic fungal diversity associated with two ethnobotanically critical medicinal plants: Withania somnifera (Ashwagandha) and Amomum subulatum (Badi Elaichi), and evaluates their biomedical potential against clinically significant human pathogens. Healthy leaves, stems, and roots were subjected to a stringent multi-step surface sterilization protocol and inoculated onto Potato Dextrose Agar (PDA). A total of fifteen (15) distinct fungal endophytes were isolated and taxonomically characterized via macroscopic and microscopic morphotyping. The predominant genera identified included Aspergillus, Fusarium, Alternaria, Curvularia, Penicillium, and Phoma. The cell-free secondary metabolites were extracted using organic solvents and screened for antibacterial efficacy against Klebsiella pneumoniae, Staphylococcus aureus, Escherichia coli, Salmonella typhi, and Micrococcus spp. using the agar well diffusion assay. The bioprospecting profile revealed significant inter-species variability. Notably, Aspergillus flavus derived from W. somnifera exhibited a profound, broad-spectrum zone of inhibition against both Gram-positive and Gram-negative cohorts, with optimal metabolic yield quantified at a 7-day incubation kinetics threshold. These insights underscore the therapeutic relevance of plant-associated fractions as sustainable alternatives to combat escalating multi-drug resistance (MDR) phenotypes.
