Characterization and in vitro antibacterial activity of saponin-conjugated silver nanoparticles against bacteria that cause burn wound infection.

Saponins are glycosides, which destabilize the membrane by altering the membrane permeability. Thus, the present study was aimed to fabricate the silver nanoparticles (AgNPs) using fenugreek derived saponin (SN) against multi-drug resistant bacteria. This study has optimized the concentration of SN (240 mg/mL) for the synthesis of an effective AgNPs against the test organism Escherichia coli. The SN reduced AgNPs produced a reddish-brown colour and displayed UV absorption at 416 nm. The bio-reducing efficiency of SN (62.76%) was calculated from the HPLC quantitation of free SN in the colloidal solution of AgNPs. The FESEM-EDAX analysis of SN-AgNPs revealed a spherical shape and showed signals for elemental silver along with carbon and oxygen. The spherical morphology of SN-AgNPs was also confirmed from its TEM and AFM micrographs and their sizes were found in between 2-15 nm. The hydrodynamic size, zeta potential and crystalline nature of SN-AgNPs were studied by DLS and XRD analyses and were found to be 9-30 nm, -18 mV and fcc crystallinity respectively. The FT-IR analysis of SN-AgNPs revealed that the functional groups such as C-O, C=C, C=O and O-H of SN are involved in the reduction and stability of AgNPs. The SN-AgNPs have depicted a notable in vitro structural stability and showed a remarkable antibacterial activity against the bacterial species, related to severe burn wound infections. In conclusion, the findings of our study clearly demonstrate that the SN-AgNPs conjugate would be a novel effective antibacterial agent for the prevention/eradication of multi-drug resistant bacterial infections in severe burn wounds.