Antimicrobial kinetics of Alstonia scholaris bark extract-mediated AgNPs

Green synthesis of silver nanoparticles using dietary antioxidant rutin and its biological contour

Background

Dietary and wholesome antioxidant rutin is considered advantageous due to its potential protective role for numerous diseases related to oxidative stress, high safety, cost-effectiveness, and extensive biological effects. The present study accounts for an expeditious method for the synthesis of silver nanoparticles (AgNPs) using rutin.

Results

The presence of AgNPs was affirmed by UV–visible spectroscopy at 425 nm, and FESEM and zeta sizer analysis revealed the average size of the AgNPs 80–85 nm and 160 d.nm, respectively. Zeta potential measurements (− 30.3 mV) showed that the AgNPs have reasonably good stability. Element mapping analysis of the AgNPs was confirmed by XRD and AFM, while FTIR spectra of the AgNPs showed the existence of functional groups. In the DPPH assay, highest radical scavenging activity of AgNPs, 86.95 ± 01.60%, was confirmed. The interaction of AgNPs with CT-DNA and HS-DNA was studied spectrophotometrically, and the data display a shift in the respective spectra. Furthermore, interaction with pBR322 DNA, λ DNA, CT-DNA, and HS-DNA was deliberated by a nicking assay that shows the physicochemical properties of AgNPs. Antibacterial activity was evaluated by the standard well-diffusion method against Escherichia coli and Staphylococcus aureus, and cytotoxicity was assessed against human WBCs by MTT assay.

Conclusion

As per this appraisal, it can be concluded that it is a cost-effective, simple, and eco-friendly tactic and such NPs are beneficial to improve therapeutics since the antioxidant, DNA interaction, antibacterial, and cytotoxic exploits offer a new horizon of euthenics.

Green synthesis of silver and gold nanoparticles using Stemona tuberosa Lour and screening for their catalytic activity in the degradation of toxic chemicals

In the present study, silver and gold nanoparticles (AgNPs and AuNPs) were green synthesised using the aqueous plant extract of Stemona tuberosa Lour. When plant extract was mixed with AgNO₃ and HAuCl₄ solutions in separate reactions, the amalgamated solutions turned deep reddish brown and dark purple in colour after 48 h indicating the formation of AgNPs and AuNPs. UV-Visible analysis of green synthesised AgNPs and AuNPs have shown absorption maximum at 443.85 nm and 539.72 respectively after 48 h. Energy dispersive X-ray spectroscopy (EDX) analysis confirmed the presence of pure silver in the green synthesised AgNPs and pure gold in the plant-mediated AuNPs. X-ray diffractometer (XRD) data revealed the face-centred cubic nature of AgNPs. Fluorescence transmission infrared (FTIR) spectrum has shown the characteristic peaks of different phytochemicals in the plant extract which acted as stabilising or capping agents of AgNPs. Scanning electron microscopy (SEM) analysis of AgNPs and AuNPs revealed that the nanoparticles are monodispersed. Transmission electron microscopy (TEM) studies revealed that AgNPs were mostly spherical with an average size of 25 nm whereas selected area electron diffraction (SAED) analysis confirmed their crystalline nature. Both AgNPs and AuNPs of S. tuberosa Lour have shown potential catalytic activity in the presence of sodium borohydride (NaBH₄) in the degradation and removal of 4-nitrophenol, methylene blue, methyl orange and methyl red.