Di‐Rhamnolipid From Nocardiopsis dassonvillei B2: A Multifunctional Therapeutic Agent With Anticancer, Antibacterial, and Antibiofilm Activities

An indigenous bacterial strain, designated Nocardiopsis dassonvillei B2, was isolated and identified as a producer of glycolipid biosurfactants, specifically di‐rhamnolipids. The present study focuses on purification, characterization, and biological evaluation of the di‐rhamnolipid biosurfactant. A purified di‐rhamnolipid fraction was obtained using silica gel column chromatography, and its molecular structure was characterized using a combination of infrared (IR) spectroscopy, two‐dimensional nuclear magnetic resonance (2D NMR), and electrospray ionization mass spectrometry (ESI‐MS). The data confirmed that the compound was di‐rhamnolipid, containing two rhamnose sugar molecules attached with fatty acid chain and with mass value 649.93. The NRU assay demonstrated a dose‐dependent decline in cancer cell viability, with IC 50 values of 97.16 ± 0.2 µg/mL for MCF‐7, 217.3 ± 0.5 µg/mL for HCT‐116, and 284.7 ± 0.2 µg/mL for HaCaT cells. The underlying mechanism of action is hypothesized to involve the induction of apoptosis. The di‐rhamnolipid exhibited notable antibacterial activity, with a minimum inhibitory concentration (MIC) of 5 µg/mL against both Gram‐positive and Gram‐negative bacteria, as determined by the agar diffusion method. Furthermore, its strong antibiofilm activity was confirmed against biofilm‐forming pathogens, effectively. These findings establish di‐rhamnolipid as a promising candidate for biomedical applications, including cancer therapy, antimicrobial treatment, and biofilm inhibition, underscoring its potential as a multifunctional therapeutic agent. Practical applications : Nocardiopsis dessonvillei var. B2 produces a di‐rhamnolipid biosurfactant with excellent surfactant and biological activities, similar to other biosurfactant producing strains like Pseudomona s species. Compared to other bacteria, this strain belongs to the class of actinobacteria and is non‐pathogenic to humans, making it very safe for biosurfactant production. The biosurfactant was produced using olive oil as carbon source, as the strain efficiently utilized the oil and generate biosurfactant, which can be useful for the bioremediation of oil contaminated soils, water bodies and other industrial wastes. Further the produced biosurfactant shows potential anticancer, antibiofilm, and antibacterial activities.