Ecofriendly Synthesis of CuO Nanoparticles Using <i>Brassica Juncea</i> (L.) Czern Seed Extract: A Green Approach for Effective Biological Applications

Abstract Copper oxide nanoparticles were synthesized by ecofriendly method using aqueous extract of Brassica juncea (L.) Czern seeds. Thus, obtained BJ‐CuO NPs were characterized using TEM, EDX, Raman spectra, DLS, zeta potential, UV–vis, FTIR, XRD, and SEM techniques. XRD analysis revealed monoclinic structure with 18 nm crystallite size. SEM studies confirmed the spherical morphology of produced BJ‐CuO NPs, further supported through TEM analysis (17.67 ± 5.45 nm). Raman spectra showed peaks at 292, 340, and 626 cm −1 , which is attributed to Raman active modes for Cu–O stretching (Ag + 2Bg). The stability of the colloidal suspension was proved through DLS analysis with zeta potential value of −34.5 mV. The BJ‐CuO NPs had shown significant biological activities with IC 50 values in µg/mL, namely, i) antioxidant (72.21), ii) anti‐inflammatory (77.77), and iii) antidiabetic activity (71.36). Further, the cytotoxicity studies on A549 and MCF‐7 cell lines through MTT test reveals moderate effect with IC 50 values of 40.68 and 86.62 µg/mL. On screening BJ‐CuO NPs for antibacterial and antifungal activity against various strains, it shows significant activity with E. coli (18 ± 0.30) and A. Niger (18 ± 0.61). These results indicate that BJ‐CuO NPs hold significant potential for biological applications in future drug development.