Biosynthesis of gold nanoparticles mediated by medicinal phytometabolites: An effective tool against plasmodium falciparum and human breast cancer cells

Gold nanoparticles (AuNPs) were synthesized using leaf extracts obtained from the medicinal plants Abutilon theophrasti Medik., Origanum majorana L., Euphorbia hirta L., and Senna auriculata (L.) Roxb. The in vitro antimalarial and anticancer activities of AuNPs were assessed against blood-stage malaria parasites and human breast cancer cells, respectively. AuNPs were examined using UV-VIS spectroscopy, HRTEM, DLS, zeta potential, XRD, and FTIR. All the AuNPs exhibited the surface plasmon resonance (SPR) band around 530 nm, which supports the formation of gold particles. The FTIR indicated possible bioactive molecules as constituents of the AuNPs formed. The assay of SYBR Green I, which is based on fluorescence, was utilized to investigate the anti-plasmodial action of AuNPs on the erythrocytic phases of 3D7 (chloroquine drug-sensitive) and INDO (chloroquine drug-resistant) strains of Plasmodium falciparum. The anti-plasmodial IC50 values of the synthesized A. theophrasti AuNPs (N1), O. majorana AuNPs (N2), E. hirta AuNPs (N3), and S. auriculata AuNPs (N4) were 76, 60, 32, and 20 against Pf3D7, and >100, 48, 72, and 36 μg/mL against PfINDO, respectively. N4 showed the highest activity against both P. falciparum strains and also exhibited a high CC50 (480 μg/mL) against human embryonic kidney (HEK293) cells, which leads to a great selectivity index of 24. The in vitro anticancer potential of AuNPs (N1, N2, N3, and N4) was assessed on MCF-7 cells, and the IC50 values were 8.25, 20.25, 20.40, and 24.49 μg/mL, respectively. The study revealed a dose-dependent increase in anticancer potential. The present study demonstrated that AuNPs derived from plant extracts may be useful therapeutic agents for treating human breast cancer and malaria.