Green Synthesis of Chromium Oxide Nanoparticles for Antibacterial, Antioxidant Anticancer, and Biocompatibility Activities

This study deals with the green synthesis of chromium oxide (Cr₂O₃) nanoparticles using a leaf extract of Abutilon indicum (L.) Sweet as a reducing and capping agent. Different characterization techniques were used to characterize the synthesized nanoparticles such as X-ray diffraction (XRD), Scanning electron microscope (SEM), Transmission electron microscope (TEM), Energy-dispersive X-ray (EDX), Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), and ultraviolet-visible (UV-VIS) spectroscopy. The X-ray diffraction technique confirmed the purity and crystallinity of the Cr₂O₃ nanoparticles. The average size of the nanoparticles ranged from 17 to 42 nm. The antibacterial activity of the green synthesized nanoparticles was evaluated against four different bacterial strains, E. coli, S. aureus, B. bronchiseptica, and B. subtilis using agar well diffusion and a live/dead staining assay. The anticancer activities were determined against Michigan Cancer Foundation-7 (MCF-7) cancer cells using MTT and a live/dead staining assay. Antioxidant activity was investigated in the linoleic acid system. Moreover, the cytobiocompatibility was analyzed against the Vero cell lines using MTT and a live/dead staining assay. The results demonstrated that the green synthesized Cr₂O₃ nanoparticles exhibited superior antibacterial activity in terms of zones of inhibition (ZOIs) against Gram-positive and Gram-negative bacteria compared to plant extracts and chemically synthesized Cr₂O₃ nanoparticles (commercial), but comparable to the standard drug (Leflox). The green synthesized Cr₂O₃ nanoparticles exhibited significant anticancer and antioxidant activities against MCF-7 cancerous cells and the linoleic acid system, respectively, compared to chemically synthesized Cr₂O₃ nanoparticles. Moreover, cytobiocompatibility analysis displayed that they presented excellent biocompatibility with Vero cell lines than that of chemically synthesized Cr₂O₃ nanoparticles. These results suggest that the green synthesized Cr₂O₃ nanoparticles' enhanced biological activities might be attributed to a synergetic effect. Hence, green synthesized Cr₂O₃ nanoparticles could prove to be promising candidates for future biomedical applications.