Gold nanoparticles bioreduced by natural extracts of arantho (Kalanchoe daigremontiana) for biological purposes: physicochemical, antioxidant and antiproliferative evaluations

Abstract

An easy green chemistry method was developed for the biosynthesis of gold nanoparticles using different extracts of arantho (Kalanchoe daigremontiana), a medicinal plant commonly used in traditional medicine for cancer treatment. Gold nanoparticles were obtained by a simple bio-reduction process using arantho extracts with different polarities. Light scattering, microscopy, spectroscopy, and electrochemical analysis were performed to characterize the mean particle diameter, morphology, and composition of the nanoparticles. Antioxidant, antiproliferative and toxic effects were determined using a range of in vitro biological assays: TEAC, ORAC, MTT, LDH, and hydrogen peroxide production. The extracts of arantho were shown to be able to form and stabilize gold nanoparticles with different sizes and morphologies. UV–vis, ATR-FTIR, and electrochemical assays demonstrated that the gold nanoparticles formed were coated by metabolites present in each arantho extract. Biological assays indicated that the coated gold nanoparticles possessed antiradical and reducing properties and the ability to inhibit the proliferation of HT29 cancer cells and to modulate cellular peroxides, unlike gold nanoparticles obtained by the traditional Turkevich method. The solvent used to isolate each extract impacted the toxicity of the bioreduced gold nanoparticles. Overall, our results suggest that gold nanoparticles synthesized using arantho’s extracts have the potential to be used as antioxidants or antiproliferative agents within the biomedicine and pharmaceutical fields for future applications.