Phytochemical‐Mediated Copper Oxide Nanoparticles Using <i>Cheilocostus speciosus</i> and <i>Gardenia gummifera</i> : Design, Synthesis, and Antimicrobial Evaluation Through In Silico and In Vitro Approaches

Abstract In this study, we synthesized copper oxide nanoparticles using leaf extracts of two Indian medicinal plants, Cheilocostus speciosus (CS) and Gardenia gummifera (GG) , for the first time. The environmentally sustainable synthesis of CuO NPs from Cu(NO 3 ) 2 uses phytochemical capping and stabilizing properties. UV‐DRS, X‐ray diffraction (XRD), Fourier transform‐infrared (FT‐IR), XPS, SEM‐EDS, and TEM‐SAED confirmed CS‐CuO and GG‐CuO NP structure and morphology. UV‐DRS diffuse reflectance spectra show two absorption bands at 218–350 and 406–554 nm. Functional group studies of CS‐CuO and GG‐CuO NPs were done using FT‐IR. XRD patterns of CS‐CuO and GG‐CuO NPs show monoclinic phases and average sizes of 4.62 and 11.85 nm. Morphological studies used SEM‐EDX and TEM‐SAED. Biosynthesized CuO‐NPs were tested against Gram‐negative, Gram‐positive, Aspergillus niger , and Candida albicans . CS‐ and GG‐CuO NPs inhibited Escherichia coli and Staphylococcus aureus with 18‐ and 16‐mm zones, respectively. Bioinspired CuO NPs kill many bacterial strains, making them useful in nanobiotechnology. Molecular modelling determined the S. aureus nucleoside diphosphate kinase receptor's bonding affinity and inhibition probability with phytochemicals present in the leaf extract. In silico pharmacokinetics studies and prediction of physiochemical parameters predicted the drug‐likeness and non‐toxic behavior of the phytochemicals. Overall, current research demonstrates an environmentally sustainable synthesis of CuO nanoparticles utilizing leaf extracts from CS and GG, providing a sustainable and non‐toxic alternative to traditional methods. The antimicrobial efficacy of these nanoparticles against bacterial and fungal strains addresses the growing demand for novel strategies to counter microbial resistance. In addition, in silico molecular modelling and pharmacokinetics studies further emphasis the drug‐likeness and safety of phytochemicals, underscoring their significance in nanobiotechnology and drug development. This multidisciplinary approach illustrates the extensive relevance and significance of our efforts in promoting green chemistry and antimicrobial strategies.