Cytotoxic and antibacterial activities of starch encapsulated photo-catalyzed phytogenic silver nanoparticles from Paeonia lactiflora flowers

This work reports the cytotoxic and antibacterial activities of starch encapsulated phytogenic silver nanoparticles synthesized from Paeonia lactiflora flowers (PLF-AgNPs). To optimize the synthesis of AgNPs, a total of 13 reactions were performed with the different combinations of AgNO3 (1-5 mM), plant extract (5-15% v/v), and light exposure time (0-48 h). The UV-spectrum results indicated that AgNPs were not produced without the light exposure while the light exposure significantly triggered the production of AgNPs. Among the various combination of plant extracts, AgNO3 concentration, and light exposure, only four combinations were successfully formed the AgNPs and they were named as PLF-AgNPs (1:5:48), PLF-AgNPs (3:5:24), PLF-AgNPs (3:15:3.5), and PLF-AgNPs (3:5:3) according to their ratio of AgNO3:plant extract:light exposure time. The physicochemical properties of newly synthesized all the NPs were studied using the various characterization techniques including FTIR, XRD, and FE-TEM, EDS. The encapsulation of the starch was significantly reduced the toxicity of AgNPs in the NIH3T3 cell line and LN229 cell line evidenced by cytotoxicity, AO/EB, and DACF-DA staining assay. Besides, ST-PLF-AgNPs has inhibited the bacterial growth higher than the PLF-AgNPs with MIC of 3.91 +/- 0.11, 1.63 +/- 0.09, 2.86 +/- 0.39, 1.95 +/- 0.24 mu g/mL for Listeria monocytogenes, Staphylococcus aureus, Escherichia coli, and Salmonella enterica, respectively. The present results proved that encapsulation of the starch reduced the cytotoxicity by increasing the antibacterial activity of ST-PLF-AgNPs, which is deserved for biotherapeutics analysis to treat bacterial infections.

Automated summary

This study investigated the cytotoxic and antibacterial activities of starch-encapsulated phytogenic silver nanoparticles synthesized from Paeonia lactiflora flowers. The encapsulation of starch significantly reduced the toxicity of AgNPs in cells and increased their antibacterial activity.