Biological activities and cytogenotoxicity evaluation of green synthesized corn silk-mediated silver nanoparticle

Abstract

Nanoparticles have been proven to have a wide range of applications due to their peculiar properties. Of the metallic nanoparticles, green synthesized silver nanoparticles (AgNPs) have been widely used in various applications. This study evaluated the potentials of corn silk extract in the synthesis of silver nanoparticles (CS-AgNPs), its biological activities as well as safety. Powdered corn silk (1g) was warmed in 100 ml of distilled water at 60°C for 1h, cooled, and centrifuged at 4000 rpm for 30 minutes. Then, 1 ml of the extract was added to 40 ml of 1mM AgNO3 to reduce Ag+ to nano size. Characterization of CS-AgNPs was by UV-visible spectroscopy, Fourier-transform-infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and Energy Dispersive X-ray (EDX) analysis. The efficacy of CS-AgNPs as a larvicidal, anticoagulant, thrombolytic, and antioxidant agent was evaluated. Safety evaluation was carried out using Allium cepa assay where 0.01, 0.1, 1.0, 10.0, and 100.0 μg/ml of the CS-AgNPs, and Ag-salt, as well as CS-extract were used. Twenty (20) onions were exposed per concentration while distilled water was used as diluent and control. Data were analyzed through Analysis of variance and Duncan tests. The CS-AgNPs were dark brown with a surface Plasmon reso-nance peak at 436 nm. FTIR revealed the availability of biomolecules responsible for capping and stabilizing agents. TEM revealed nanoparticles of size range 8.48-45.78 nm. The CS-AgNPs caused 100% mortality of exposed Anopheles mosquito larvae in 12 h and showed a good anticoagulant and thrombolytic potential on human blood for the prevention of blood clots. Anti-oxidant activity using DPPH and H₂O₂ scavenging assays revealed the potential of CS-AgNPs in absorbing and neutralizing free radicals. The synthesized CS-AgNPs and Ag-salt solution induced more chromosomal aberrations at 24 and 48 h and only Ag-salt solution induced more aberrant cells at 72 h. Root growth inhibition observed correlates with the observed mitotic inhibition at higher concentrations especially for CS-AgNPs. Mitodepressant potentials especially at higher concentrations can be explored as an anticancer agent along with other established potentials.