Onosma inexspectata and Onosma armenum as Novel Sources of Phytochemicals with Determination by High-Performance Liquid Chromatography-Mass Spectrometry (HPLC-MS/MS) with Evaluation of the Antioxidant and Enzyme Inhibitory Capacities

The goal of the current work was to study the phytochemical content of Onosma inexspectata Teppner and O. armenum DC. The antioxidant properties using six assays and the enzyme inhibitory capacities against alpha-amylase, alpha-glucosidase, tyrosinase, and the anti-cholinesterase were also evaluated. The levels of phenolic compounds were approximately 22 and 28 mg gallic acid equivalent/g for O. inexspectata and O. armenum, respectively. Twenty-seven compounds were identified and quantified using liquid chromatography-electrospray ionization tandem mass spectrometry. Chlorogenic acid, apigenin 7-glucoside, and luteolin 7-glucoside were the major compounds in O. inexspectata. Onosma armenum contained an attractive level of hesperidin. The antioxidant assays showed significant differences between the two species, except for the phosphomolybdenum assay. The results of the inhibitory enzyme assays revealed no significant differences between the extracts, except for alpha-glucosidase inhibition. The present study may underline the possibility to use O. inexspectata and O. armenum as promising sources of phytochemicals that may serve against many body disorders.