Silver nanoparticles fabricated by tannic acid for their antimicrobial and anticancerous activity

The present investigation reports a simple and environmentally benign synthesis of nanosized silver involving tannic acid both as a reducing and stabilizing agent. Different analytical tools were used to estimate the exact composition, morphology, and characterization of silver NPs. A sharp surface plasmonic resonance (SPR) band at 410 nm confirms the formation of silver NPs with an optical band gap of 2.36 eV evaluated by UV–visible spectroscopy. Powdered X-ray diffraction analysis shows that the silver NPs were crystallized in a cubic crystal structure and a particle size average of 16.82 nm was computed by transmission electron microscopy. As evidenced by Fourier transformed infrared spectroscopy, tannic acid was an excellent reductant in forming silver NPs from silver ions. Dynamic light scattering noticed the negative charge distribution over the surface of stabilized silver NPs. The present work is mainly devoted to provide significant efforts in developing cancer medicine by fabricating silver NPs. Therefore, the cytotoxic activity against adherent human lung carcinoma cells A549 was evaluated, and the minimal inhibition concentration (MIC or IC50) value was ∼ 300 μM observed (in vitro). It reveals that the silver NPs synthesized by tannic acid were reliable to be an excellent anticancerous agent. Likewise, the antimicrobial activity of silver NPs was also tested by using the disc diffusion method. The gram-negative/positive bacterial strains were used are Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Staphylococcus aureus. However, Candida tropicalis, Candida parapsilosis, and Candida albicans strains were used for antifungal activity. The moderate inhibition activity against bacterial strain was noticed compared to that of fungal strain. This report shows that the tannic acid-mediated silver NPs can be potentially used for removing pathogenic factors and effectively utilized as an anticancerous drug.