Synthesis, characterization and multifunctional biological evaluation of nanocomposites of silver and plant derived carbon dots from Mirabilis jalapa

Carbon dots (CDs) derived from plant biomass have emerged as sustainable nanomaterials with excellent surface functionalization, reducing capacity for the synthesis of metal nanoparticles. In this study, CDs derived from Mirabilis jalapa leaves were utilized as dual-function reducing and stabilizing agents to fabricate AgNP@CD nanocomposites (NCs). The formation of nanocomposite was confirmed by a characteristic surface plasmon resonance (SPR) peak at ~ 427 nm along with the presence of O-H and N-H groups, indicating effective surface passivation. The morphological analysis revealed moderately agglomerated NCs with an average size of 42.51 nm. The NCs exhibited excellent broad-spectrum activity with the lowest MIC of 3.9 µg mL⁻¹ observed against Streptococcus pyogenes . The moderate antioxidant activity was found with an IC 50 value of 141.51 µg mL⁻¹ (DPPH), whereas α-amylase inhibitory activity revealed an IC 50 value of 85.62 µg mL⁻¹. The cytotoxicity activity on SH-SY5Y neuroblastoma cells showed an IC 50 concentration of 158.24 µg mL⁻¹, indicating preliminary anticancer potential. Therefore, the present study revealed effective multifunctional in vitro bioassays of AgNP@CD NCs, which are suitable for further in vivo evaluation.