Radical Scavenging Activity and Total Phenolic Content in Methanolic Extracts of Leaves and Male Inflorescence Catkin of Willow

Background: Phenolic compounds are widely distributed secondary metabolites which are produced by plants and considered as potent antioxidants. Objective: Total phenolic and flavonoid contents and antioxidant properties were assessed in leaf and male inflorescence catkin tissues of five Salix species grown in Iran. Methods: The methanolic extracts of leaf and male inflorescence were subjected to determination of total phenolic and flavonoid content. The antioxidant capacity of each sample was measured by 2,2 - diphenyl -1 - picrylhydrazyl (DPPH), superoxide, nitric oxide and hydrogen peroxide radical scavenging activity. Results: In the leaf extracts, the highest values for total phenolic and flavonoid contents were obtained for S. matsudana (4.93 mg GAEs/ g) and S. aegyptiaca (215.78 mg CEs/ g), respectively. In the male inflorescence catkin extracts, the highest value for total phenolic belonged to S. babylonica (52.70 mg GAEs/ g) and S. excelsa showed the maximum flavonoid content (635.52 mg CEs/ g). In the leaf extracts, the radical inhibition for DPPH ranged from 40.08% (S. excelsa) to 91.94% (S. aegyptiaca) and S. excelsa showed the highest superoxide (99.00%) and nitric oxide (71.73%) scavenging activities. The same level of hydrogen peroxide radical scavenging activity (50%) was observed for S. matsudana, S. acmophylla and S. babylonica. In the male inflorescence catkin extracts, S. excelsa (70.63%), S. acmophylla (60.25%) and S. matsudana (62.37%) showed the highest radical inhibition for DPPH, nitric oxide and hydrogen peroxide, respectively. The S. excelsa, S. aegyptiaca and S. babylonica displayed 99% superoxide radical inhibition. Conclusion: The catkin extracts showed more phenolic content than leaf extracts of species. The potent antioxidant activity of Salix supports its possible use as a natural antioxidant in food industries and other pharmaceutical preparations.