Phytofabrication of Chitosan-MgO nanocomposites: Evaluation of their antioxidant, antibacterial, anticancer, and zebrafish embryo biocompatibility properties.

Phytofabrication of polymer-based nanocomposites has emerged as a promising approach for developing multifunctional biomaterials with enhanced therapeutic efficacy. In the present study, chitosan-coated magnesium oxide nanocomposites (CS-MgONCs) were successfully synthesized via a green biogenic route using Abutilon indicum leaf extract, integrating the advantages of biopolymers and metal oxides. The formation of CS-MgONCs was preliminarily confirmed by UV-Vis spectroscopy with a characteristic absorption peak at 280 nm. FTIR analysis revealed the involvement of key functional groups responsible for reduction and stabilization, while XRD patterns confirmed the crystalline nature of the nanocomposites. HR-TEM demonstrated a predominantly semi-spherical morphology with an average particle size of 58.93 nm. DLS and zeta potential analyses indicated good colloidal stability, with a surface charge of +8.76 mV, attributed to the chitosan coating. Functionally, CS-MgONCs exhibited significant dose-dependent antioxidant activity, achieving a maximum DPPH radical scavenging efficiency of 78.37 ± 1.34% at 200 μg/mL. The nanocomposites also demonstrated potent antibacterial activity against both Gram-positive and Gram-negative pathogens, with notable zones of inhibition against Staphylococcus aureus (20.71 ± 0.74 mm) and Escherichia coli (19.71 ± 0.74 mm). Furthermore, marked anti-inflammatory activity was observed through inhibition of cyclooxygenase (COX), with 77.58 ± 1.37% suppression of COX-2 activity, suggesting effective modulation of inflammatory pathways. Biocompatibility assessment in zebrafish embryo models indicated acceptable safety profiles, with a 70% survival rate at 200 μg/mL. Importantly, the nanocomposites exhibited pronounced anticancer activity against HT-29 colon cancer cells, reducing cell viability to 21.48 ± 0.98% in a concentration-dependent manner. In conclusion, the findings highlight that biogenically synthesized CS-MgONCs integrate structural stability with multifunctional biological performance, positioning them as promising candidates for future biomedical and therapeutic applications.