Green synthesis and characterization of Bi₂O₃ nanoparticles using Cuminum cyminum seed for antimicrobial and cytotoxic evaluation

Green synthesis provides an alternative to traditional chemical processes of nanomaterials preparation, which is cost-effective and environmentally benign. This paper has demonstrated synthesis of bismuth oxide nanoparticles (Bi 2 O 3 NPs) using Cuminum cyminum seed extract as a natural reducing and stabilizing agent of bismuth nitrate precursor. The formation of nanoparticles was first signaled by a change of color of reaction mixture to be visible and subsequent analysis by physicochemical characterization. The UV-Visible spectroscopy displayed absorbance at 300 nm, and FTIR gave results that showed Bi-O-related absorption and phytochemical functional groups, which indicated the formation of bismuth oxide nanoparticles stabilized by plant-derived biomolecules. The crystalline character of the nanoparticles produced was verified by X-ray diffraction analysis with estimated crystallite size of approximately 136.9 nm. SEM analysis revealed irregular and strongly agglomerated structures. Image analysis of clearly distinguishable agglomerates indicated apparent dimensions of approximately 0.20–2.00 μm, with highest frequency in the 0.60–0.80 μm interval; however, individual primary particles could not be resolved reliably. The Bi₂O 3 nanoparticles biosynthesized had antimicrobial and antifungal effects against Escherichia coli , Staphylococcus aureus , Candida albicans , and Aspergillus niger with Candida albicans being the most sensitive. Furthermore, cytotoxicity studies revealed that HeLa and MCF-7 cell proliferation were greatly inhibited by synthesized nanoparticles, which indicates the possibility of biomedical applications of the synthesized nanoparticles. All in all, this work shows an easy and environmentally friendly path to green synthesis of Bi 2 O 3 nanoparticles using Cuminum cyminum seed extract and reflects on their potential to have antimicrobial and cytotoxic capabilities.