Green synthesis of bioactive silver nanoparticles from Hippophae salicifolia leaves with antimicrobial and anticancer efficacy

Utilising an extract from the leaves of the Hippophae salicifolia plant, the present study synthesises silver nanoparticles, characterises them thoroughly, and further evaluates their biological activity. The silver ions in the aqueous silver nitrate solution were reduced by the methanolic leaf extract, and the bioactive compounds were further characterised by GC-MS analysis. UV-Vis spectroscopy, X-ray diffraction, and scanning electron microscopy were employed to characterise the synthesised AgNPs, and it was reported to have an average particle size of 50.40 nm. This study also uniquely links the bioactive content of certain bioactive compounds, such as dimethyl sulfone, fatty acid esters, and siloxanes, with nanoparticle stabilisation as well as their biological activity. Moreover, it also emphasises the antibacterial potential of phytosynthesised AgNPs, particularly against P. aeruginosa, as well as their dose-dependent anticancer potential against the A549 lung cancer cell line. This approach also extends the translational potential of Himalayan medicinal flora for green nanotechnology as well as nanomedicine. Dimethyl sulfone (35.1%) and cyclopentasiloxane decamethyl (18.69%) are the major ones among the eight major phytochemicals identified. AgNPs showed enhanced activity against Gram-negative bacteria, particularly S. aureus (18.7±0.9mm), followed by P. aeruginosa (15.9±0.7mm), whereas the leaf extract showed enhanced inhibition zones against Gram-positive bacteria compared to gentamicin in the disc diffusion assay. The cytotoxic activity of AgNPs was evaluated by the MTT assay against A549 lung cancer cells, and the results indicated a dose-dependent reduction in cell viability, with an IC50 value of activity of 180.2 ± 0.18 µg/ml. Based on these findings, H. salicifolia-mediated AgNPs may have potential applications as antibacterial and anticancer drugs.