Green Synthesis of Silver Nanoparticles from Extracts and Evaluation of Antioxidant, Antimicrobial and Anti-Quorum Sensing Potential.

The biosynthesis of silver nanoparticles (AgNPs) from leaves and stem bark extracts is described. The stem bark AgNPs of synthesized at 80 °C (S80) showed good scavenging activity with a lower IC value of 8.75 µg·mL compared to ascorbic acid (9.58 µg·mL). The total phenol content of the S80 AgNPs was measured and found to be 10.22 ± 0.14 mg.g gallic acid equivalence (GAE). Bacterial growth inhibition (% GI) and violacein inhibition (% VI) of 10.08% and 58.83%, respectively, was observed against CV017 with leaf AgNPs synthesized at 80 °C (L80) at 80 μg·mL. Stem bark AgNPs synthesized at room temperature (SRT) also indicated % GI of 13.83% and % VI of 65.97% against CV017 at 160 μg·mL. Leaf AgNPs of synthesized at room temperature (LRT), showed % GI of 29.07% and % VI of 56.53%, respectively, against ATCC 12472 at 320 μg·mL. The L80 and SRT at 160 μg·mL and LRT at 320 μg·mL may be considered as potential QS inhibitors following their activity against CV017 and ATCC 12472, respectively. Therefore, represents a potential source of antioxidants as well as an anti-quorum sensing therapeutic candidate for the control of Gram-negative bacterial infections.