Comparison of the Influence of the Solvent on the Extraction of the Bioactive Compounds from Marrubium lutescens Using Liquid Chromatography-Electrospray Ionization Tandem Mass Spectrometry (LC-ESI-MS/MS)

To our knowledge, this is the first study on the influence of water, ethyl acetate and methanol as the extraction solvent upon the bioactive compound composition, antioxidant capacities and enzyme inhibitory activities of Marrubium lutescens isolates. The contents of the total phenolic compounds varied between 9.94 and 54.80 mg gallic acid equivalent/g extract and the level of total flavonoids were between 4.45 and 27.20 mg quercetin equivalent/g extract. Twenty-four compounds were identified using liquid chromatography - electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). Rosmarinic acid, luteolin 7-glucoside, chlorogenic acid, caffeic acid and hyperoside were the primary compounds present for all of the used solvents. The most compounds (23) were detected in the methanol extract. Six antioxidant assays revealed that M. lutescens extracts showed interesting antioxidant activities with a significant variation between the extracts. The results revealed that the highest tyrosinase and alpha-amylase inhibitory activities was detected in the ethyl acetate extract. This work confirmed that the nature of solvent influenced the levels and the types of the extracted biomolecules. Moreover, the obtained results suggest that M. lutescens may be a source of bioantioxidants for industrial additives.