Comprehensive bioactivity and chemical characterization of the endemic plant Scorzonera hieraciifolia Hayek extracts: A promising source of bioactive compounds.

Members of Scorzonera genus are known for their potential application in both food and pharmaceutical industries. The present study reports the chemical component and bioactivity of the dichloromethane, ethyl acetate, hexane, methanol and infused extracts of Scorzonera hieraciifolia Hayek aerial parts and roots. The methanolic extracts of both aerial parts and roots were good sources of total phenolic and flavonoid content. For the aerial parts, the infused and methanolic extracts showed highest (p < 0.05) free radical scavenging (2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS)), reducing (cupric reducing antioxidant capacity (CUPRAC))and ferric reducing antioxidant power (FRAP)) and metal chelating capacities. Whilst, for the root extracts, overall most remarkable free scavenging and reducing activity was observed for the methanolic extracts (p < 0.05) while the hexane extracts showed highest metal chelating activity. The inhibitory activity of the extracts was evaluated against key enzymes. Overall, the hexane extracts of both aerial parts (acetylcholinesterase (AChE): 2.27 ± 0.04 and butyrlcholinesterase (BChE): 5.75 ± 0.48 mg galantamine equivalent (GALAE)/g) and roots (AChE: 2.44 ± 0.35 and BChE: 53.17 ± 0.22 mg GALAE/g) were most potent against AChE and BChE, suggesting a role for the more lipophilic compounds in this regard. The highest inhibitory activity against tyrosinase was displayed by methanolic extracts of aerial parts (64.70 ± 0.26 mg kojic acid equivalent (KAE)/g) and roots (63.63 ± 0.20 mg KAE/g). Modest activity was observed against α-amylase and α-glucosidase, two major enzymes implicated in the pathology of diabetes. Liquid chromatography-mass spectrometry (LC-MS) and nuclear magnetic resonance (NMR) analysis showed the presence of 40 compounds such as caffeic, ursolic, betulinic and oleanolic acid and their derivatives in the studied extracts. Multivariate analysis showed that the biological activities were dependent on the plant parts used as well as on the type of solvent used. Overall, the results showed that S. hieraciifolia is a valuable source of phytochemicals for both the nutraceutical and pharmaceutical sectors.