In the current study, we investigated the anticancer potential against human colon cells (Caco-2) of colloidal nanosilver (CN–Ag) produced in Syria using bioactive compounds in the aqueous extract of Eucalyptus camaldulensis leaves (AEECL). The formation of AgNPs was confirmed by UV-visible spectroscopy analysis with surface plasmon peak at 449 nm and their average size was found to be 12, 10, 23 nm by SEM, DLS and NTA respectively. This small size has confirmed the effective role of AEECL as capping agent. Further morphological characterization was done by EDS showed the presence of metallic silver. Zeta potential value (-23 mV) indicated the repulsion among the particles and stability of the formulation nanosilver. The anticancer effect of synthesized CN–Ag against Caco-2 has been tested. The cytotoxicity assay showed a dose-dependent and a time-dependent effect of CN–Ag. The high cytotoxicity of CN–Ag at low concentration (5μ/mL) open new prospects for the development of novel therapeutic approaches against human colon cancer Caco-2.

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Backround and Objectives: A simple and eco- friendly green method was successfully used to synthesis of nano colloidal silver (NCS) using an aqueous extract of Eucalyptus camaldulensis leaves, which acts as a reducing and capping agent. Method: The goal of this work is to ensure the ability of aqueous extract of Eucalyptus camaldulensis leaves which is widely available in our region cheap and has high antioxidant activities as reducing agent for synthesis of silver nanoparticles. Total phenolic content of extract was evaluated by the well-known colorimetric assay using Folin Ciocalteu reagent. DPPH and ABTS scavenging methods were applied to assessment the antioxidant activities The formation of silver nanoparticles is tested by various techniques like UV-Vis, FTIR-spectroscopy and X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray spectrum (EDX) and Dynamic Light Scattering (DLS). The advantage of our method lies on the fact that Eucalyptus camaldulensis extract acts both as a reducing agent and a stabilizer of silver nanoparticles. Results and Conclusion: The rapid change of color from yellowish to dark brown within 10 min indicate the high ability of Eucalyptus camaldulensis aqueous extract to reduce Ag+ ions to Ago. FTIR measurements indicated the presence of amine groups which play as capping agent to prevent agglomeration of silver nanoparticles.