Green Synthesis of Gold Nanoparticles Using Pimpinella affinis Leaf and Stem Extracts and Evaluation of Their Cytotoxic Effects Against Human Breast Cancer Cells Under In-vitro Condition

 Nowadays, one of the great challenges of mankind is to find a suitable way for the treatment of cancer. Recent developments show that nanotechnology has a significant impact on the prevention, diagnosis and treatment of cancer. In nanotechnology, there are different physical and chemical methods to produce nanoparticles but mostly chemical methods are used. The nanoparticles produced using these methods are harmful to health due to the absorption of chemical species on their surface. In order to eliminate this big problem, biological methods such as the use of fungi, bacteria and plants have replaced other methods for the synthesis of nanoparticles which is called green synthesis. It is cheaper, simpler and non-toxic than other methods. The use of plants for the synthesis of nanoparticles has become more important than other biological methods due to the elimination of the difficult step of cell culture maintenance.

 In this study, gold nanoparticles were formed after treating the HAuCl4 solution with the aqueous extract of Anarijeh plant with the scientific name Pimpinella affinis. In this research, different amounts of aqueous extracts of leaves and stems of Pimpinella affinis were used for the synthesis of gold nanoparticles. UV-Visible spectroscopy and DLS methods were used to evaluate nanoparticles and determine their average size and stability. Also, SEM method was used to investigate their morphology. FTIR method was used to determine the functional groups of the aqueous extract and synthesized gold nanoparticles; in addition GC/MS device was used to determine the composition of the extract. Finally, MTT analysis was used to investigate the cytotoxic effects of nanoparticles on MCF-7 cell line along with treatments of 24, 48 and 72 hours.

 The results of the analysis were showed that the optimal concentration of the Pimpinella affinis extract for the synthesis of gold nanoparticles is 1 mg/ml. The synthesized gold nanoparticles using the mentioned concentration of the extract have an average size of 20 nanometers with a zeta potential of -61 mV which has the best stability. They had a spherical shape with a polydispersity equal to 0.7. The results of FTIR analysis show the presence of hydroxyl, simple carbonyl groups and hydrocarbon functional groups in the compounds of the extract. Experiments showed that phenolic and carboxylic compounds play the most important role in the reduction of gold salt. Also, proteins and lipids have made gold nanoparticles stable. The essential compounds identified in the extract by GC/MS method include Phenolic and flavonoid compounds and terpenes which are confirmed by the FTIR spectrum. The treatment time of 48 hours for MCF-7 cell line is the best time for the toxicity of nanoparticles with IC50 equal to 384.2 µg/ml, which was determined by MTT analysis.

 According to the above findings, it can be concluded that Pimpinella affinis is one of the suitable options for the synthesis of gold nanoparticles, and it can be done with more studies on nanoparticles synthesized using this plant, considered it as one of the efficient methods to achieve the goal of proper treatment for breast cancer.