Bioactivities of iridoids and flavonoids present in decoctions from aerial parts of Verbascum betonicifolium

Introduction: Verbascum betonicifolium (V. betonicifolium) is a plant used in traditional medicine for several ailments. The objective of this study was to determine the antioxidant activity and acetylcholinesterase inhibitory activity of the aqueous extract together with the metabolites responsible for these activities. This paper presents the first phytochemical characterization and bioactivities of aqueous extracts from aerial parts. Methods: The compounds present in the aerial part aqueous extract were identified by high performance liquid chromatography, coupled to a diode-array detector (HPLC-DAD) and by high-resolution mass spectrometry (HRMS), using LC-MS/MS analyses. Antioxidant activity was measured as the capacity to scavenge the free radical DPPH and the AChE activity was determined using the Ellman test. The cytotoxicity was determined used HepG2 cell lines. Results: Several types of metabolites were found, primary metabolites (malic, citric and gluconic acids), phenolic compounds (verbascoside, luteolin), terpenoids (iridoid glycoside, unedide), among others. The total phenol content of 28 mu g of gallic acid equivalents/mg of extract was determined. The aqueous extract antioxidant activity had and EC50 of 70 mu g/mL and the AChE inhibitory activity an IC50 of 750 mu g/mL. No cytotoxicity towards HepG2 cells was detected, even using a concentration of 1 mg/mL. Conclusions: The phenolic compounds present in the extract may be the main contributors to the bioactivities of V. betonicifolium. These results show for the first time the richness of phytochemicals and the strong bioactivities of V. betonicifolium and that the aqueous extract could be used as new natural sources of bioactive molecules.