Background: Colorectal cancer (CRC) ranks as the third most common cancer globally and the second leading cause of cancer-related mortality. Traditional chemotherapy, while effective, often results in significant side effects, highlighting the need for more efficient cancer therapies. Recent advancements in nanotechnology have led to the development of strategies that aim to minimize toxicity to normal cells by more precise targeting of cancer cells. In this context, cobalt oxide nanoparticles (Co3O4 NPs) have shown promising anticancer potential. Our study focuses on evaluating the antioxidant, antibacterial, and anticancer properties of Co3O4 NPs synthesized using Vibrio sp. VLC, a bioluminescent bacterium. Results: XRD and FTIR analyses confirmed the successful synthesis of Co3O4 NPs, which displayed spherical morphology with an average diameter of 60 nm. The nanoparticles demonstrated significant antioxidant and antibacterial activities. The MTT assay indicated that the NPs caused dose- and time-dependent toxicity against CT26 cells, while exhibiting relatively lower toxicity towards normal cells. In vivo experiments further confirmed the significant tumor suppressive effects in BALB/c mice, with minimal side effects on the liver, spleen, and kidney tissues compared to the widespread toxicity of cisplatin. Conclusion: This study verifies the successful synthesis of Co3O4 NPs and their potent antioxidant, antibacterial, and anticancer activities. The biosynthesized Co3O4 NPs represent a promising targeted method for CRC therapy. However, further research is needed to elucidate their mechanism of action and also their application in the clinical phase.

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