Multifunctional SrO₂–Sodium Alginate–L-Arginine Nanocomposite: A Green Approach against Colon Cancer and Pathogenic Microbes

Pathogenic microbes pose a significant threat to human health due to their increasing resistance to standard antibiotics. Colon cancer is among the deadliest forms of cancer worldwide and often exhibits resistance to conventional treatments, highlighting the urgent need for alternative therapeutic agents. In this study, a SrO₂–SA–LA nanocomposite was synthesized via a green chemical approach using Bougainvillea glabra extract and evaluated for its anticancer, antioxidant, and antimicrobial potential. In this work, SrO₂-SA-LA nanocomposite was prepared via a green chemical approach using Bougainvillea glabra extract and evaluated for its potential anticancer, antioxidant, and antimicrobial properties. The nanocomposite was successfully synthesized and functionalized, as confirmed by characterization studies. XRD revealed a crystalline phase of tetragonal SrO₂. The calculated optical bandgap energies were 4.11 eV for pristine SrO₂ and 4.35 eV for SrO₂-SA-LA nanocomposite. DLS analysis indicated median particle sizes of 128.40 nm and 142.70 nm for SrO₂ and SrO₂–SA–LA, respectively. PL studies showed that the SrO₂–SA–LA nanocomposite exhibited green emission in the range of 494–534 nm, suggesting an increase in oxygen-related defect states compared to pure SrO₂. Disc diffusion assay revealed that SrO₂-SA-LA nanocomposite exhibited enhanced antimicrobial activity against common disease-causing pathogens, while MTT assay showed enhanced cytotoxicity against HCT-116 colon cancer cells. Additionally, the SrO₂-SA-LA nanocomposite exhibited superior free radical scavenging in DPPH assays, indicating high antioxidant potential. Furthermore, cytocompatibility studies using L929 fibroblast cells confirmed that both SrO₂ and SrO₂–SA–LA nanocomposite are non-toxic to normal cells, with cell viability exceeding 80%, indicating their biosafety. The results suggest that SrO₂-SA-LA nanocomposite is a promising candidate for applications in anticancer, antioxidant, and antimicrobial therapies with good biocompatibility.