The exploitation of different plant leaves extracts for the biosynthesis of nanoparticles is considered as a new and recent ecofriendly and cost effective technique because it doesn't involve any harmful chemicals beside its beneficial properties and broad spectrum applications in diverse fields. In this context gold nanoparticles (GNPs) and iron oxide nanoparticles (IONPs) were biosynthesized, for the first time, in one-step green method via reduction of gold aureate and ferric chloride solutions with 70% aqueous ethanolic (AE) extract of Corchorus olitorius (C. olitorius) leaves. Preliminary screening of the extract revealed the presence of a wide array of phytochemicals including phenols, flavonoids, tannins, proteins, carbohydrate, soluble sugars and polysaccharides. Quantitative estimation of these phytochemicals were 385.4±3.6, 564.61±4.6, 92±2.0, 766.9±6.1, 255.7±5.7 and 131.1±2.9 mg/ml, respectively. HPLC analysis of the phenolic and flavonoid contents of the leaves extract asserted the presence of gallic acid, chlorogenic acid, caffeic acid, rutin, p-coumaric acid, rosmarenic acid, 5-caffeoylquinic acid, quercetin 3-glucoside and myricetin in percentages of 59.47, 9.68, 2.32, 1.81, 1.53, 1.68, 1.40, 1.45 and 1.81, respectively. These phytoconstituents act as reductants and stabilizers for the biosynthesized gold and iron oxide NPs. The formed NPs were characterized by using UV-Vis absorption spectroscopy; Fourier transformed infrared spectroscopy (FT-IR); X-ray diffraction (XRD) and transmission electron microscopy (TEM). The biosynthesized NPs were found to exhibit high percentage scavenging activity of DPPH radical with percentage inhibition of 91.90 and 80.51% for GNPs and IONPs, respectively, at a concentration of 100mg compared to both effects of the leaves extract 76.62% and ascorbic acid 94.27% at the same concentration. In addition, the results obtained from the in vitro cytotoxic studies showed that these NPs exhibited the growth inhibitory property at IC50 % of 6.97 and 5.82 for GNPs and IONPs, respectively, against MCF 7 breast cancer cell lines in comparison with the leaf extract effect 9.77% and standard drug effect 3.95%. These data provide strong evidence that GNPs and IONPs should be studied further as potential novel free radical as well as cytotoxic agents.
