Chemical analysis and antioxidant activities of bark extracts from four endemic species of Hyrcanian forests in Iran

Abstract

Abstract Chemical analysis of the bark from four Hyrcanian forest species, Pterocarya fraxinifolia, Alnus subcordata, Gleditsia caspica and Parrotia persica were performed, and their total phenol contents, and antioxidant and chelating activities were evaluated. The greatest total phenol content (TPhC), 54.3% in dry extract, was detected in P. fraxinifolia bark and the lowest one in G. caspica bark with 4.5%. The 50% inhibitory concentrations (IC50) in the radical-scavenging assay against DPPH radicals in bark acetone extracts of P. fraxinifolia, A. subcordata, G. caspica and P. persica were 0.17, 0.21, 13.35, 0.19 mg ml−1, respectively. In the metal-chelating activity system, G. caspica extract demonstrated significant activity. Pterocarya fraxinifolia, A. subcordata and P. persica bark acetone extracts revealed a high potential for inhibition of DPPH radicals due to high amounts of phenolics. Superior health benefits can be expected from the compounds syringol, 4-vinylguaiacol, tyrosol, chavicol, resorcinol, hydroquinone, vanillin, rheosmin and acetophenone. Gleditsia caspica was found to have significant chelating activity due to isoeugenol.