Green one pot synthesis of silver nanoparticles for antioxidant and antimicrobial activities

Trigonella foenum-graceum L. (variety HM 444) seeds are an excellent source of phenolics, flavonoids, and sugars, which serve as reducing, stabilizing, and capping agents for the reduction of silver ions to AgNPs. Various phytochemicals such as total phenolic content (5.37 ± 0.14 mg GAE/g), total flavonoids (1.43 ± 0.03 mg CE/g), total sugars (41.44 ± 0.61 mg/g), reducing sugars (0.73 ± 0.02 mg/g) and non- reducing sugars (40.71 ± 0.58 mg/g) were reported in aqueous seed extract. Their ability to mediate AgNPs biosynthesis was evaluated. The synthesized AgNPs were characterized by UV-Vis spectroscopy, particle size analyser, XRD, FESEM-EDX, HRTEM, SAED and FT-IR Spectroscopy. The average size of the AgNPs was 27 nm and they were spherical in shape. The AgNPs showed better 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity with a lower IC₅₀ = 620.00 µg/mL as compared the aqueous seed extract (IC₅₀ = 623.33 µg/mL). AgNPs exhibited significant antimicrobial activity against Staphylococcus aureus, Xanthomonas spp., Macrophomina phaseolina and Fusarium oxysporum compared to the aqueous seed extract. According to this study, AgNPs may be a contender for various biological, nutraceutical, and sustainable antimicrobial food packaging applications.