Rhizome of Anemarrhena asphodeloides as mediators of the eco-friendly synthesis of silver and gold spherical, face-centred cubic nanocrystals and its anti-migratory and cytotoxic potential in normal and cancer cell lines.

The water extract of Anemarrhena asphodeloides, the traditional oriental medicinal plant, mediated the eco-friendly synthesis of silver nanoparticles (Aa-AgNPs) and gold nanoparticles (Aa-AuNPs). First, its therapeutic rhizome was powdered prior to water extraction and then silver, gold nanoparticles were synthesized. Aa-AgNPs and Aa-AuNPs were found to be spherical, face-centred cubic nanocrystals with a Z-average hydrodynamic diameter of 190 and 258 nm, respectively. In addition, proteins and aromatic biomolecules were the plausible players associated with the production and stabilization of Aa-AgNPs; instead, phenolic compounds were responsible for the synthesis and stability of Aa-AuNPs. In vitro cytotoxic analysis revealed that up to 50 μg.mL-1 concentration Aa-AuNPs did not exhibit any toxicity on 3T3-L1, HT29 and MCF7 cell lines, while being specifically cytotoxic to A549 cell line. On the contrary, Aa-AgNPs displayed a significantly higher toxicity in comparison to Aa-AuNPs in all cell lines specially MCF7 cell line. Since cancer cells were more sensitive to Aa-Au/AgNPs treatments, further evaluation was done in order to determine their anticancer potential. Reactive oxygen species (ROS) generation was not affected by Aa-AuNPs, on the other hand, Aa-AgNPs treatment exhibited a higher potential to induce oxidative stress in A549 cells than HT29 and MCF7 cells. In addition, Aa-Ag/AuNPs reduced cell migration in A549 cells at 10 and 50 μg.mL-1, respectively. So far, this is the only report uncovering the ability of A. asphodeloides to synthesize silver and gold nanoparticles with anticancer potential and also indirectly enabling its large-scale utilization with value addition.