Antioxidant and antimicrobial activity of different extracts of Pistacia atlantica leaf

The objective of this study was to investigate the antioxidant and antimicrobial activities of the ethanol (EE), methanol (ME), and water (AE) extracts from the leaf of Pistacia atlantica subspecies mutica which naturally grown in Iran. The total phenol content and antioxidant activity of extracts were determined using spectrometric method according to the Folin–Ciocalteu phenol reagent and scavenging effect on DPPH (2,2-diphenyl-1-picrylhydrazyl) radicals. The extracts were evaluated for their antimicrobial activity against three Gram-positive, three Gram-negative bacteria and one yeast by assay for minimum inhibitory concentration (MIC) and minimum bacterial concentration (MBC) using disc diffusion method. Results showed that the water extract had the highest total phenol content. But EC50 of water extract was 5.87 compared with BHT as synthetic antioxidant (3.94 mg/ml). The water extract with higher level phenolic compounds and scavenging DPPH showed the highest antioxidant and antibacterial effects, in comparison with the other extracts. It was found to be effective against all the test organisms with Gram positive strains being more sensitive than Gram negative strains. Also, the water extract were the most effective against the examined bacteria and yeast species, based on its higher content of phenolic compounds. Among the examined microorganisms, Streptococcus faecium and Candida albicans were found to be the most sensitive and resistant, respectively. According to finding of this study, water extract of Pistacia atlantica leaf could be used as a natural preservative in the food industry.