Isolation and characterization of bioactive fractions with anti cancer and anti microbial potential from bacterial isolates

Abstract

The increasing global burden of cancer and the rapid emergence of antimicrobial resistance underscore the urgent need for novel therapeutic agents that combine efficacy with safety. The present study was undertaken to isolate and characterize bioactive compounds with dual anticancer and antimicrobial potential from bacterial endophytes associated with the medicinal plants Phyllanthus niruri and Pithecellobium dulce. A total of fifty-one morphologically distinct endophytic bacterial isolates were obtained, of which three exhibited significant bioactivity. Among these, isolate RSS2 demonstrated the highest biosurfactant yield along with superior surface-active properties. Physicochemical and spectroscopic characterization identified the bioactive fraction as a rhamnolipid-type glycolipid biosurfactant. Antimicrobial evaluation revealed broad-spectrum activity, including effective inhibition of drug-resistant bacterial pathogens at low minimum inhibitory concentrations. Anticancer activity was evaluated against NCI-H23 lung cancer and Jurkat leukemia cell lines using MTT-based cytotoxicity assays, which showed concentration- and time-dependent growth inhibition with defined ICand#8325;and#8320; values. Mechanistic validation using Annexin V FITC and propidium iodide staining confirmed apoptosis as the predominant mode of cell death. Notably, the biosurfactant exhibited selective cytotoxicity towards cancer cells with minimal toxicity to normal cells, indicating favorable therapeutic selectivity. By integrating microbial bioprospecting, bioactivity-guided purification, and mechanistic evaluation, this study establishes endophyte-derived rhamnolipids as promising multifunctional bioactives. The findings provide a sustainable and biologically rational framework for the development of low-toxicity, biodegradable therapeutic agents addressing both cancer progression and antimicrobial resistance, with potential relevance for future biomedical applications. newline