Spectroscopic interaction study of human serum albumin and human hemoglobin with Mersilea quadrifolia leaves extract mediated silver nanoparticles having antibacterial and anticancer activity

This study looks into a safe, proficient and low-cost way for the preparation of novel silver nanoparticles by using 5% aqueous leaves extract of a medicinal plant, Marsilea quadrifolia (family: Marsileaceae) without using any external reducing and stabilizing agents. The synthesized AgNPs showed maximum UV Vis absorbance at 435 nm due to surface plasmon resonance (SPR). The average diameter (similar to 22.5 nm) of AgNPs was measured from TEM analysis and was also supported by FE-SEM. The existence of a silver signal in EDX spectra supported the AgNPs formation and negative zeta potential value (-18.7 mV) which suggested its stability. FT-IR spectroscopic analysis showed that the functional groups like -O-H, -N-H and -C=O were responsible for the synthesis of AgNPs. The antibacterial activity of the AgNPs was tested against E. coli ATCC 25922. The anticancer potential of AgNPs was also assessed using two different cell lines, such as MCF-7 and HeLa. The interaction study of AgNPs with human serum albumin (HSA) and human hemoglobin (Hb) was performed by means of UV Vis, fluorescence spectroscopy, Circular dichroism (CD) and zeta potential measurement. More negative zeta potential values of AgNPsHSA/Hb (-21.1/-19.5 mV) complexes than AgNPs (-18.7 mV) indicated corresponding stability of bioconjugates. The basic structure of HSA/Hb remained unchanged and its secondary structure was slightly changed upon interaction with the AgNPs concluded from Circular dichroism. So, it can be predicted that this AgNPs may be applied in the medical field. (C) 2017 Elsevier B.V. All rights reserved.