Green synthesis of Copper Oxide/Carbon nanocomposites using the leaf extract of Adhatoda vasica Nees, their characterization and antimicrobial activity

Abstract

Copper Oxide/Carbon (CuO/C) nanocomposites were developed through the green method using the leaf extract of Adhatoda vasica at room temperature. Here, the leaf extract serves as a capping agent, reducing agent and a source of carbon for the formation of nanocomposites. As we know, this is the first article on the synthesis of CuO/ C nanocomposites using this leaf extract. The nanocomposites were prepared by mixing the copper sulphate pentahydrate solution with the plant extract under certain conditions. The synthesized material was characterized by XRD, UV-Visible, FTIR, FE SEM, EDS, XPS and TGA. The results revealed that the synthesized material is a composite of copper oxide and functionalized graphene-like carbon. The SEM images indicated that the CuO/C nanoflakes had an average thickness of 7-11nm. Further, the composites were examined for antifungal activity and antibacterial activity. The nanocomposites showed significant antibacterial activity against the pathogenic bacterial strains Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae and Staphylococcus aureus and antifungal activity against the fungi Aspergillus niger and Candida albicans. Also, the Minimum Inhibitory Concentration (MIC) and Minimum Fungicidal/Bactericidal Concentration (MFC/MBC) of the nanocomposites were determined against the fungus C. albicans and the bacteria K. pneumonia.

Compositions and antimicrobial properties of binary ZnO–CuO nanocomposites encapsulated calcium and carbon from Calotropis gigantea targeted for skin pathogens

“…Calcium was observed to have six characteristic peaks at 28.80°, 50.47°, 58.89°, 66.70°, 67.70°, and 73.92°. The additional peaks detected at 31.53° and 40.94° were attributed to the natural graphene-like carbon present in the BZC nanocomposites 54 as carbon is the main phytochemical element in the leaves of the C. gigantea medicinal plant 55 .…”

“…The main novelty of this study was the detection of pythochemical elements such natural calcium 56 and carbon 54 , 57 in leaf extract, which could further boost the antimicrobial activity of BZC nanocomposites. Calcium and carbon elements have never been reported before in the studies of Sharma et al, Gawade et al, and C R Rajith Kumar et al performed on the same C .…”

“…Moreover, free ions from natural organic carbon and calcium derived from C . gigantea leaf extract played an important role in exerting the synergic effect that killed MDR microbes at very low concentrations 54 , 56 .…”

“…At 24 h, the bacteria were completely killed. Thus, Gram-positive S. aureus bacteria were effectively controlled by the synergistic combination of 75 wt% of ZnO and 25 wt% of CuO nanoparticles in the presence of natural graphene-like carbon, calcium, and phytochemical constituents such as cardiac glycosides, tannins, saponins, terpenes, flavonoids, and phenolics in C. gigantea leaf extract 54 , 56 , 65 – 68 .

Figure 5 Time-kill curves against S. aureus strains using 2.5 mg/mL of green B3Z1C sample for 0.5 h (30 min), 3 h, 6 h, 12 h and 24 h treatment periods.

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Calcination Temperatures, Compositions and Antimicrobial Properties of Heterostructural ZnO–CuO Nanocomposites from Calotropis Gigantea Targeted for Skin Ulcer Pathogens

“…[39]. The additional peaks detected at 29.47° and 40.78° are attributed to the natural graphene-like carbon present in the ZnO-CuO nanocomposites [42] as carbon is a main phytochemical element in the leaves of the C. gigantea medicinal plant [43,44]. Natural carbon in binary ZnO-CuO nanocomposites could further enhance the synergic effect on antimicrobial activity [45,46].…”