Antioxidant potential, enzyme inhibitory activity and HPLC-MS/MS phenolics profiles in Salvia aegyptiaca L. (Lamiaceae, Nepetoideae, Mentheae) growing in Tunisia

The present study aimed to assess for the first time the antioxidant and enzyme inhibition activities of phenolic secondary metabolites of Tunisian Salvia aegyptiaca extracted using different solvents (methanol, ethyl acetate, chloroform and hexane). The phytochemical composition was examined via HPLC-MS/MS. The evaluation of the antioxidant effects involved the utilization of multiple techniques including phosphomolybdenum, antiradical (DPPH and ABTS), reducing power (FRAP and CUPRAC), and ferrous chelating assays. Additionally, the inhibitory activity was tested on different enzymes: α-amylase, α-glucosidase, acetylcholinesterase, butyrylcholinesterase, and tyrosinase. The HPLC examination of various extracts revealed the quantification of 11 phenolic acids, 11 flavonoids, along with ellagic and trans-cinnamic acids. The chloroform extract was predominated by the presence of syringic acid (4665.38 mg/Kg) while the highest accumulation of caffeic acid (3058.47 and 2593.19 mg/Kg), kaempferol (4675.33 and 4025.04 mg/Kg) and hesperidin (8449.26 and 3705.82 mg/Kg) were recorded in methanol and ethyl acetate, respectively. Our findings demonstrated that the Tunisian S. aegyptiaca extracts exhibited a notable α-amylase and α-glycosidase inhibitory capabilities. It is worthy to note that the crude methanolic extract demonstrated the strongest antioxidant properties, and it was the richest source of total phenolic constituents.