Phenolic composition and antioxidant activity of aqueous and ethanolic leaf extracts of six Tunisian species of genus Capparis – Capparaceae

• Leaves samples of six taxa of Capparis-Capparaceae were collected from different locations in Tunisia.
• Evaluation and identification of phenolic components by HPLC and antioxidant activities (DPPH and ABTS).
• The results showed significant variation in the content and composition of the total polyphenols and flavonoids of Capparis taxa studied.
• A significant correlation between radical scavenging capacities with total phenolic was revealed.

Leaves of species of the genus Capparis are consumed as food and used in traditional medicine. In the present work, phenolics profile and antioxidant activities of six taxa of Capparis collected in Tunisia (C. aegyptia, C. orientalis, C. ovata subsp. ovata, C. sicula subsp. sicula, C. spinosa subsp. spinosa var. spinosa and C. zoharyi) were studied. The ethanolic and aqueous leaves extracts were analyzed by HPLC and 10 compounds were identified with significant variability between species. Moreover, DPPH and ABTS tests revealed their high antioxidant activities. Kaempferol was only found in the ethanol extract of C. zoharyi and cinnamic acid in that of C. aegyptia. Capparis spinosa subsp. spinosa var. spinosa is characterized by a balanced total polyphenol content. The correlation between the data of the phenolic compounds identified and the antioxidant activity revealed a clear separation between the six taxa studied. For the ethanolic extracts, in descending gradient of the three parameters TP, TF and DPPH, C. spinosa subsp. spinosa var. spinosa was separated from the other taxa whereas for the aqueous extracts C. zoharyi and C. ovata subsp. ovata were separated from the rest. These subdivisions were different from those of many studies based on morphological, biogeographical, genetic and ecological parameters which aim to review the taxonomy of this genus throughout its geographic area.