Phenolic Compounds of Phlomis tuberosa by LC–MS/MS-Determination of Antioxidant Activity, Molecular Docking, and Enzyme Inhibition Profiles

Phlomis species have traditionally been employed for the treatment of a number of ailments such as influenza, the common cold, asthma, bronchitis, coughs, hemorrhoids, ulcers, and gastrointestinal disorders. The goal of this study is to compare the anti-diabetic, anti-glaucoma, and anti-Alzheimer's properties and antioxidant activities of methanol (MEPT) and aqueous (WEPT) extracts from the aerial part of P. tuberosa L. Tandem mass spectrometry and liquid chromatography (LC–MS/MS) were used to investigate the compounds of MEPT and WEPT. The inhibitory effects of MEPT and WEPT on the enzymes acetylcholinesterase (AChE), carbonic anhydrase II (CA II) and α-glycosidase were investigated and molecular docking studies demonstrated binding interactions between the major compounds chlorogenic acid, cyanidin-3-O-glycoside, quinic acid, rosmarinic acid with AChE, CA II and α-glycosidase enzymes. In addition to that, the total content of phenols and flavonoids was analyzed. Furthermore, the antioxidant activity was evaluated by DPPH, ABTS, DMPD, ferrous ions (Fe2+) chelating, FRAP, CUPRAC, and ferric ions (Fe3+) reducing methods. This study is the first of its kind to show that MEPT and WEPT possess inhibitory effects on AChE, CA II and α-glycosidase, as well as displaying antioxidant properties.