UHPLC/HR-ESI-MS/MS Profiling of Phenolics from Tunisian Lycium arabicum Boiss. Antioxidant and Anti-lipase Activities' Evaluation

Abstract

This study was performed in the aim to evaluate nine different extracts from Tunisian Lycium arabicum for their total phenolic and total flavonoid contents, phytochemical analyses as well as their antioxidant and anti-lipase activities. The in vitro antioxidant property was investigated using three complementary methods (DPPH, ferric reducing antioxidant power (FRAP), and β-carotene-linoleic acid bleaching assays) while anti-lipase activity was evaluated using 4-methylumbelliferyl oleate method. From all of the tested extracts the most potent found to be the polar MeOH extracts especially those of stems and leaves. In order to investigate the chemical composition of these extracts and possible correlation of their constituents with the observed activities, an UHPLC/HR-ESI-MS/MS analysis was performed. Several compounds belonging to different chemical classes were tentatively identified such as rutin and kampferol rutinoside, the major constituents of the leaves, and N-caffeoyltyramine, lyciumide A, N-dihydrocaffeoyltyramine as well as fatty acids: trihydroxyoctadecadienoic acid and hydroxyoctadecadienoic acid isomers were detected abundantly in the stems. These results showed that the MeOH extracts of stems and leaves of L. arabicum can be considered as a potential source of biological active compounds.

Keywords: Lycium arabicum; Anti-lipase activity; Antioxidant activity; Polyphenols; UHPLC/HR-ESI-MS/MS.