Biofilm forming bacteria can cause serious health problems that are difficult to combat. Silver nanoparticles (Ag-NPs) synthesized from plant extracts have potential to fight and eradicate biofilmforming bacteria. In the present research, AgNPs were synthesized using leaf and bark extract of Erythrina suberosa Roxb. and Ceiba pentandra L. and their antibiofilm, antioxidant and antibacterial activity was checked. Phytochemical analysis of the plant extracts showed important bioactive compounds such as tannins, saponins, steroids, phenolics, alkaloids, flavonoids and glycosides. The AgNPs were synthesized and confirmed by visual color observation and UV-Vis spectrophotometer. Visual color observation showed that the color of the leaf and bark extracts of E. suberosa and C. pentandra turned into brown. UV-Vis spectra analysis showed absorbance peak range between 430-450 nm. The antioxidant activity of the AgNPs was determined by FRAC (Ferrous reducing antioxidant capacity) assay. Synthesized AgNPs from all sources showed significant antioxidant activity. However, antioxidant activity of E. suberosa AgNPs was significant compared to other sources. Antibacterial activity and biofilm forming assay was analyzed against Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. The synthesized AgNPs silver nanoparticles showed significant (p ≤ 0.05) antibacterial activity against all the bacteria. The maximum zone of inhibition was found in case of E. suberosa AgNPs bark extract against P. aeruginosa was 20±1.154 mm. The results of biofilm forming assay showed that the AgNPs from all sources significantly (p ≤ 0.05) inhibited the activity of biofilms by all the tested bacteria. From results, it can be concluded that AgNPs synthesized from both plants can be used in developing antimicrobial compounds.
Keywords: Ceiba pentandra; Erythrina suberosa; biofilm; phytochemicals; silver nanoparticles.