A study on phenolic compounds content and antioxidant activity of kolkhoung (Pistacia khinjuk Stocks) leaf in natural habitat of Ilam province

In the present study, the total phenolic and flavonoid contents and antioxidant activity were investigated in four kolkhoung genotypes in their natural habitats of Ilam province. The antioxidant activity of methanolic extracts were assayed by DPPH (2,2-diphenyl- 1- picrylhydrazyl), nitric oxide radical scavenging and FRAP (ferric reducing antioxidant power) assays. Among all the sample tested, leaf extract of K3 and K4 genotypes contained the highest and the lowest total phenolic and flavonoid contents, respectively. The results indicated that among all the genotypes studied here, the highest and the lowest antioxidant activity were observed in K3 and K4 genotypes, respectively. According to the results, total phenol and flavonoid contents and antioxidant activity in kolkhoung can be influenced by different factors such as genetic, environmental and ecological conditions. So that the amount of total phenolic and flavonoid contents and antioxidant activity increased in leaf of kolkhoung as the altitude increased, and the highest amount of compounds were observed in K3 genotype at altitude of 2083 meters (Ghalarang mountain). However, the results obtained in our research indicated that K3 genotype had the highest total phenolic and flavonoid contents, and interestingly this genotype revealed the highest antioxidant activity among all samples tested.