Synthesis of silver nanoparticles using Plantago lanceolata extract and assessing their antibacterial and antioxidant activities

Abstract

Silver nanoparticles (Ag. NPs) have shown a biological activity range, synthesized under different environment-friendly approaches. Ag. NPs were synthesized using aqueous crude extract (ACE) isolated from Plantago lanceolata. The ACE and Ag. NPs were characterized and assessed their biological and antioxidant activities. The existence of nanoparticles (NPs) was confirmed by color shift, atomic force microscopy (AFM), and UV–Vis’s spectroscopy. The FT-IR analysis indicated the association of biomolecules (phenolic acid and flavonoids) to reduce silver (Ag+) ions. The SEM study demonstrated a sphere-shaped and mean size in the range of 30 ± 4 nm. The EDX spectrum revealed that the Ag. NPs were composed of 54.87% Ag with 20 nm size as identified by SEM and TEM. AFM has ended up being exceptionally useful in deciding morphological elements and the distance across of Ag. NPs in the scope of 23–30 nm. The TEM image showed aggregations of NPs and physical interaction. Ag. NPs formation also confirmed by XPS, DRS and BET studies. Ag. NPs showed efficient activity as compared to ACE, and finally, the bacterial growth was impaired by biogenic NPs. The lethal dose (LD50) of Ag. NPs against Agrobacterium tumefaciens, Proteus vulgaris, Staphylococcus aureus, and Escherichia coli were 45.66%, 139.71%, 332.87%, and 45.54%, with IC50 (08.02 ± 0.68), (55.78 ± 1.01), (12.34 ± 1.35) and (11.68 ± 1.42) respectively, suppressing the growth as compared to ACE. The antioxidant capacity, i.e., 2,2-diphenyl-1-picrylhydrazyl (DPPH) of Ag. NPs were assayed. ACE and Ag. NPs achieved a peak antioxidant capacity of 62.43 ± 2.4 and 16.85 ± 0.4 μg mL−1, compared to standard (69.60 ± 1.1 at 100 μg mL−1) with IC50 (369.5 ± 13.42 and 159.5 ± 10.52 respectively). Finally, the Ag. NPs synthesized by P. lanceolata extract have an excellent source of bioactive natural products (NP). Outstanding antioxidant, antibacterial activities have been shown by NPs and can be used in various biological techniques in future research.

Strong Antimicrobial Activity of Silver Nanoparticles Obtained by the Green Synthesis in Viridibacillus sp. Extracts

“…The mentioned concentrations for total killing are very low compared to other reported green AgNPs. For instance, recently, Shah et al (2021) showed that the LD50 dose (concentration of AgNPs causing 50% inhibition) obtained from Plantago lanceolate against E. coli was 45.54 mg/L, which is much higher than the G-AgNPs MBC value (kill 100% bacteria) against E. coli, i.e., 8 µg/mL, in our study. Similarly, Devanesan and AlSalhi, 2021 demonstrated the antimicrobial activity of AgNPs originated from flower extract of Abelmoschus esculentus.…”

Antibiofilm activity of green synthesized silver nanoparticles against biofilm associated enterococcal urinary pathogens

“…These phytocompounds may play a role in stabilizing the particle size of the prepared silver metals within the nanoparticle ranges. Similar FT-IR results were reported in previous studies of green synthesized AgNPs 16 , 31 , 32 . The chemical AgNPs FT-IR spectrum peaks were corresponding to the O–H stretching/N–H stretching of an amine group and C=O groups.…”

“…According to the ICDD PDF-2 (No.071-4613) database, these lattice planes were indexed to the face-centered cubic crystal (FCC) nature of metallic silver. The average crystallite size of the AgNPs was calculated by applying the Scherrer equation 16 . Cinnamon, ginger, and chemical AgNPs' average crystallite sizes were 5.7, 10.3, and 14.6 nm, respectively.…”

“…These findings were compatible with previous studies that synthesized cinnamon and ginger AgNPs 24 , 25 . UV–visible spectroscopy was used as an effective way to confirm the synthesis of AgNPs 16 . Cinnamon and ginger AgNPs showed SPR peaks around 402.7 and 424 nm, respectively.…”

“…The XRD operation was run at 40 kV and 30 mA with Cu Kα radiation of 1.54 A° wavelength, in the 2θ range 10°–90° angle. In addition, the Scherrer equation was used to calculate the average crystallite sizes of the AgNPs 16 . A high-resolution transmission electron microscope (JEOL-JEM2100, Japan) (200 kV) was used to confirm the particle size and study the shape of the AgNPs.…”