Anti cancer activity of bimetallic nanoparticles derived from Stephania glabra of western Himalayas

Abstract

newline ABSTRACT Stephania glabra is a wild medicinal plant possessing multiple activities such as anti-cancer, antimicrobial and antioxidant potential. Different extracts and fractions were prepared and utilized for the analysis of different activities. Total phenolic and flavonoid content was estimated. Maximum phenolic content was in methanolic extract and maximum flavonoid content was in chloroform: methanol extract. Dry powder analysis revealed the presence of saponins, alkaloids and proteins.in the plant. Antioxidant activity was also analyzed by ABTS and DPPH free radical scavenging assay. Ethyl acetate extract and petroleum ether extract have the highest ABTS and DPPH radical scavenging activities. Methanolic extract has the highest anti-cancer activity while chloroform extracts and fractions have highest antimicrobial activity. The bacterial inhibition results were in compliance with the growth curve of bacteria treated with the extracts and fractions. newlineWith the advent of green synthesized nanoparticles in nano-oncology a plethora of nanoparticles have been synthesized using different biological sources. The present study has been designed to utilize Stephania glabra tuber methanol extract (Sg-ME) for the synthesis and optimization of silver nanoparticles (Sg-AgNP), copper oxide nanoparticles (Sg-CuONP) and bimetallic nanoparticles (Sg-BNP) exhibiting potent anti-cancer activity. The characterization of these nanoparticles was done by UV Vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), Dynamic light scattering (DLS), X-ray diffraction (XRD), Transmission electron microscopy (TEM), Field-emission scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy and mapping (FESEM-EDS mapping) confirming the synthesis of the nanoparticles. The field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) analysis showed the spherical structure of nanoparticles with an average diameter of approximately 30.72 nm for Sg-AgNP, 32.19 nm for Sg-CuONP and 25.59 nm for Sg-BNP. Interestingly, Sg-AgNP, Sg-CuONP and Sg-BNP exhibited significant cytotoxicity towards A549 and PC3 cell lines with IC50 values of 80.72 ± 0.05, 83 ± 0.02 and 76.52 ± 0.02 and 78.65 ± 0.11 and#956;g/ml, 83 ± 0.06 and#956;g/ml, 60.45 ± 0.03 and#956;g/ml, respectively. No toxicity was found against normal human peripheral blood lymphocytes (PBL). newlinexv newlineIncreased level of reactive oxygen species (ROS), increased mitochondrial depolarization, apoptotic cell population, presence of apoptotic bodies, activation of Caspase-3 and Poly (ADP-ribose) polymerase 1 PARP-1 and DNA fragmentation was observed in cancer cells treated with these nanoparticles and extract at the respective inhibitory concentrations. 3D prostate tumor model systems were used to further analyze the cytotoxicity and MCRI index of the nanoparticles. The cell viability was seen to decrease significantly in cells treated with Sg-BNP in 3D tumor spheroids. The percentage viability also decreased in the cells treated with Sg-AgNP however, Sg-CuONP and Sg-ME decreased the cell viability by almost 10% every day. Apart from decrease in cell viability shrinkage of spheroid was after 4 days treatment with Sg-ME, Sg-AgNP, Sg-CuONP and Sg-BNP (1.09, 6.71, 2.17 and 9.19). MCRI values indicated that the cells in 3D model system were less susceptible to the nanoparticles and extract as compared to the cells in 2D model system. Lowest MCRI (7.20) value of Sg-BNP explains that the cancer cells are sensitive to these nanoparticles. These results strongly suggest that Sg-AgNP, Sg-CuONP and Sg-BNP are capable of inducing cancer cell death in vitro and could be explored as a therapeutic nano-formulation for cancer.