Biogenic Carboxymethyl Cellulose and L‐Histidine Coated Barium Peroxide Nanocomposite: A Tri‐Functional Platform Targeting Antimicrobial Resistance, Cancer, and Oxidative Stress

The study addresses the urgent need for novel therapeutic agents in combating multidrug‐resistant pathogens, cancer, and oxidative stress‐related diseases. Barium peroxide (BaO 2 ) nanoparticles and its novel nanocomposite, carboxymethyl cellulose and L‐histidine coated BaO 2 (BaO 2 ‐CMC‐LH) were synthesized, characterized, and evaluated for their antibacterial, anticancer, and DPPH radical scavenging activities. Structural and functional characterizations were carried out using various analytical techniques. Biological evaluations demonstrated enhanced antibacterial activity against Methicillin‐resistant Staphylococcus aureus (MRSA) and Candida albicans ( C. albicans ), with BaO 2 ‐CMC‐LH exhibiting superior inhibition zones compared to BaO 2 . For MRSA, the zone of inhibition (ZOI) for BaO 2 is about 9 mm, whereas the BaO 2 ‐CMC‐LH nanocomposite exhibits a substantially larger ZOI of 21 mm. Likewise, for C. albicans , BaO 2 presents a ZOI of 12 mm, and BaO 2 ‐CMC‐LH exhibits a greater inhibition zone of 18 mm. Cytotoxicity analysis against osteosarcoma MG‐63 cells revealed significantly improved anticancer activity, with BaO 2 ‐CMC‐LH achieving an IC₅₀ value of 28.6 μg/mL compared to 53.3 μg/mL for BaO 2 . The 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) free radical scavenging assay showed that the BaO 2 ‐CMC‐LH nanocomposite (78.45%) had activity compared to BaO 2 alone (64.43%). These findings underscore the synergistic effects of the CMC‐LH matrix in enhancing BaO 2 's biological activities, positioning BaO 2 ‐CMC‐LH as a promising multifunctional therapeutic agent for addressing global health challenges.