Phytochemical Study and Comparison of Antioxidant Potential and Phenolic Content of Different Solvent Extract of Flaxseed (Linum usitatissimum L.) and Biosynthesis of Gold and SilverNanoparticles using its Extract

Flaxseed (Linum usitatissimum L.) is a member of the Lamiaceae family used in nutrition, health, and industrial products. Flaxseed accumulates many biologically active compounds, including linolenic acid, linoleic acid, lignans, cyclic peptides, polysaccharides, alkaloids, and cyanogenic glycosides. Recent research suggests that flaxseed lowers cholesterol, stabilizes blood sugar, prevents osteoporosis, helps with weight loss, strengthens the immune system, and prevents cancer. This study aimed to investigate the phytochemical, antioxidant, and phenolic content of extracts of various flaxseed solvents and the biosynthesis of silver and gold nanoparticles using these extracts.

In order to evaluate the antioxidant power and phenolic content of flaxseeds, flaxseeds extract was extracted using three different solvents, namely ethyl acetate, dichloromethane, and normal hexane by the soxhlet method. Phytochemical tests were used to identify chemical compounds. Following that, for the synthesis of gold and silver nanoparticles, HAuCl4, 3H2O, and AgNO3 salts, as well as dichloromethane extract were used in descending order. Moreover, the characterization of synthesized nanoparticles was performed by various techniques, including UltraViolet-Vis spectrophotometry. Furthermore, transmission electron microscopy and nanoparticle size analysis techniques were used to examine the size and distribution extent of nanoparticles.

After extracting different extracts of flaxseed, various phytochemical tests and different reagents were used to qualitatively identify the secondary metabolites in the extract. The results showed the presence of flavonoids, alkaloids, and steroids, as well as a lack of tannins and saponins. The highest and lowest phenolic compounds were related to the extract of dichloromethane and n-hexane of flaxseeds, respectively. The highest antioxidant properties for the extract were obtained from flaxseeds using dichloromethane solvent. After the synthesis of gold and silver nanoparticles, the colloidal solutions of the prepared nanoparticles became purple and yellow, respectively. The absorption spectra of the gold and silver nanoparticles showed maximum wavelengths of 525 and 420 nm, respectively, which indicated the characteristic wavelengths for these nanoparticles. Transmission electron microscopy studies showed that the synthesized gold and silver nanoparticles had a spherical shape with uniform distribution and mean diameters of 40 and 90 nm, respectively.

The results revealed that the use of different solvents was effective for the extraction of total phenolic content. There was also a direct relationship between the amount of total phenol and the results of measuring the antioxidant capacity of the extracts. Moreover, gold and silver nanoparticles were easily prepared using flaxseeds extract.