In-vitro antioxidant and antimicrobial activities of metal nanoparticles biosynthesized using optimized Pimpinella anisum extract

[Display omitted] •AgNPs and AuNPs were green synthesized using Pimpinella anisum seeds extract.•The effect of P. anisum extraction conditions on properties of the nanoparticles was studied.•Structural and spectroscopic characterization of the nanoparticles were determined.•Biosynthesized AgNPs showed higher antioxidant activity compared to AuNPs and P. anisum extract.•AgNPs exhibited promising anti-bacterial and anti-fungal activities. In this study, Pimpinella anisum seeds were extracted under various conditions (solvent type, temperature, solvent/plant ratio and contact time). The potency of the resulted extracts towards biosynthesis of silver and gold nanoparticles was assessed. The most potent extract towards reduction of both Ag+ and Au3+ ions was obtained using 70% methanol at 60 °C, with a solvent/plant ratio of 10 mL/g and extraction time for 60 min. The prepared nanoparticles were structurally characterized by UV–vis, transmission electron microscope, dynamic light scattering and zeta potential analysis. Phenolics and carbohydrates present in P. anisum were characterized as the active biomolecules responsible for metal ion reduction; based on FT-IR and phytochemical analysis. Further, silver and gold nanoparticles were tested for their free radical scavenging activity against 1,1-diphenyl-2-picryl-hydrazyl (DPPH), and antimicrobial activity against Escherichia coli, Staphylococcus aureus, Aspergillus flavus and Candida albicans using disk diffusion method. Biosynthesized AgNPs showed higher antioxidant and antimicrobial activities compared to AuNPs and P. anisum extract. The foregoing results suggest that P. anisum seeds extract can be extensively used in green production of potential antioxidant and antimicrobial AgNPs for safe biomedical application.