Investigation of antioxidant activity and application of HPLC technique for analysis of phenolic compounds of Amygdalus haussknechtii leaf extract

This study was conducted to investigate antioxidant compounds contents and antioxidant activity of three Amygdalus haussknechtii genotypes in the natural habitat of Ilam Province. Total phenolic content was measured using Folin–Ciocalteu method and antioxidant activity was estimated by two methods, namely DPPH (2,2-diphenyl- 1- picrylhydrazyl) and nitric oxide radical scavenging. High- performance chromatography was used for quantitative estimation of the phenolic compounds. Results showed that antioxidant activity of leaf extract of H3 genotype was significantly higher than that of H1 and H2 genotypes. The high antioxidant activity can be attributed to higher total phenolic and flavonoid contents, so that high correlation coefficient was observed between total phenolic content and DPPH and nitric oxide radical scavenging, R = 0.902 and R= 0.806, respectively. Analyzing the phenolic compounds by HPLC method indicated that catechin, sinapic acid, quercetin, and apigenin were found in H3 genotype. Also, apigenin compound was observe in all three investigated genotypes. Generally, the results suggested that leaf extract of H3 genotype with high phenolic and flavonoid content and antioxidant activity can be presented as a source of natural antioxidant and used in pharmaceutical industries.