A Comparative Study Between the Leaf and Flowers of Some Asteraceae Plants With Respect to Their Antioxidant Activity Compounds

Background: Nowadays, medicinal plants used in folk medicine are being increasingly studied and used on pharmaceutical, food and nutraceutical fields. The Asteraceae family as an essential source of phytochemical compounds is a large family of flowering plants with worldwide distribution. Further research on their multiple biological effects such as antioxidant activity and other aspects is needed. Objective: The aim of the current study was to determinate the antioxidant and radical scavenging activity of various extracts from leaf and flowers of five species (Artemisia absintium L., Arctium lappa L., Silybum marianum L., Centaurea cyanus L. and Echinops ritro L.) of the Asteraceae family. Methods: The samples extracted with absolute ethanol and methanol solvent and then extracts obtained were screened for total phenolic content (TPC), total flavonoid content (TFC), total antioxidant capacity (TAC) and chain breaking activity (CBA). Thio barbituric acid (TBA), 2, 2-diphenyl- 1-picrylhydrazyl (DPPH), IC50, nitric oxide (NO), hydrogen peroxide (H2O2), superoxide (O2 -) radical inhibition, ferric reducing antioxidant power (FRAP) were, also, measured. In addition, HPLC (High Performance Liquid Chromatography) of phenolic compounds was used. Results: Significant differences were found in phenolic content of leaf and flowers while radical scavenging capacity percentage greatly varied among species and their leaf and flowers. A positive relationship between TPC and FRAP (r2=0.810) was found in all cases. A. absintium L. and A. lappa L. leaf extracts showed the highest antioxidant activity. A. lappa L. flower had the maximum radical scavenging activity. The major phenolic compound identified in the S. marianum L. flower was sinapic acid. Conclusion: A. absintium L. and A. lappa L. are good source of natural antioxidants and could be used to prevent free radical induced deleterious effects.