In vitro evaluation of antibacterial activity and associated cytotoxicity of biogenic silver nanoparticles using various extracts of Tabernaemontana ventricosa

The development of innovative nanocomposites and their applications to a range of goods and technologies with antimicrobial properties has received increasing interest. However, recently, researchers have been concerned about the toxic effects of silver nanoparticles (AgNPs) on cellular systems. Hence, this study aimed to evaluate the biogenic AgNPs' antibacterial activity and associated cytotoxic effects using various extracts of Tabernaemonta ventricosa. AgNPs synthesized using leaf and stem extracts were subjected to the disc diffusion technique for testing against Gram-negative and Gram-positive strains, and the antibacterial efficacy of the produced AgNPs was evaluated. Conversely, the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) test was used to assess the cytotoxic potential of NPs on several cell lines, including the human cervical cancer cell line (HeLa), MCF-7, and human embryonic kidney (HEK293) cells. The most potent antibacterial suppression against Bacillus subtilis, Escherichia coli, methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus aureus, and Pseudomonas aeruginosa was demonstrated by AgNPs that were made utilizing both powdered leaf (PL) and fresh leaf (FL) extracts, which showed the highest zone of inhibition of 15.33 ± 0.58 mm. However, in HeLa, the AgNPs produced using FL extracts showed high cytotoxic effects with a half-maximal inhibitory concentration (IC₅₀) of 0.39 μg·mL^-1. These findings suggest that the synthesized AgNPs using T. ventricosa extracts display adequate antibacterial activity but also some toxic effects.