Enhancing the secondary metabolite and anticancer activity of Echinacea purpurea callus extracts by treatment with biosynthesized ZnO nanoparticles

Narges Karimi, Mandana Behbahani, Ghasem Dini and Amir Razmjou

Abstract

This investigation was done to study the effect of green synthesized ZnO nanoparticles (NPs) on the anticancer activity of callus extracts of Echinacea purpurea in comparison with commercial ZnO microparticles (MPs). Leaf explants of E. purpurea were grown on the Murashinge and Skoog (MS) medium containing different concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D) and naphthalene acetic acid (NAA). Callus induction at optimum concentrations were considered under both light and dark conditions. Among media with diverse concentrations of 2,4-D and NAA, fast-growing friable callus was started within three weeks after culturing on the MS medium containing 2.0 mg 2, 4-D l^-1. After adding different concentrations of synthesized ZnO NPs and ZnO MPs to the culture medium containing 2 mg 2, 4-D l^-1, the effect of ZnO NPs on the anticancer activity of plant extracts and callus biomass was found positive contrary to the control and ZnO MPs. However, these extracts did not have any cytotoxic activity on MCF-10 cells and peripheral blood monolayer cells. The frequency and intensity of CD4 expression on peripheral blood monolayer cells was not increased in the presence of all extracts. The highest flavonoid production of the extracts was also achieved in calli treated with different concentration of ZnO NPs. Therefore, it can be concluded that there is a direct relationship between the anticancer activity of E. purpurea and flavonoid contents