Synthesis, Characterization and Evaluation of Antioxidant and Cytotoxic Potential of Annona muricata Root Extract-derived Biogenic Silver Nanoparticles

Eco-friendly synthesis of biogenic silver nanoparticles (AgNPs) employing plants is becoming increasingly attractive for biomedical applications including cancer diagnosis and treatment. The present study deals with the biosynthesis of AgNPs using root extract from Annona muricata (AMR), optimization of physico-chemical parameters for the effective synthesis and evaluation of their antioxidant and cytotoxic potential. UV–Vis / FTIR spectroscopy, XRD, FESEM and EDX techniques confirmed the surface plasmon resonance at 440 nm of the crystalline, spherical AgNPs capped with phytoconstituents. AMRAgNPs exhibited strong antioxidant activity also showed selective cytotoxicity against HCT116, without affecting growth of normal human lymphocytes and erythrocytes. Light, fluorescence and scanning electron microscopy revealed apoptosis-related cytomorphological alterations and increase in ROS levels whilst clonogenic assay confirmed reduction in colony formation capacity in AMRAgNPs treated cells. Flow cytometric analysis revealed increase in the sub-G1cell population indicative of apoptosis induction. The expression profile of the apoptosis-associated genes, PUMA, caspase-3, -8, -9, Bax and Bcl-2 obtained through qRT-PCR, combined with the presence of p53 and p21, cleaved PARP, caspase-3, -9, on western blots unambiguously confirmed occurrence of mitochondrial apoptosis. The present study highlights the selective apoptogenic activity of the A.muricata root extract-derived AgNPs which can serve as a potent anticancer agent for colon cancer.