A comparative study of chemical profiling and biological effects of Doronicum orientale extracts

In this study, the aerial part and root extracts obtained using solvents of different polarity (hexane, ethyl acetate, ethanol, ethanol/water, and water) of one of the species of Doronicum genus, D. orientale were subjected to phytochemical and pharmacological screening. For instance, the extracts yielded total phenolic and flavonoid contents in the range of 12.13−45.67 mg GAE/g and 0.75−12.44 mg QE/g, respectively, while the total antioxidant capacity of the extracts determined by the phosphomolybdenum assay ranged from 0.88−2.53 mmol TE/g. HPLC-MS/MS analysis revealed 5-caffeoylquinic acid (2.52−337.05 µg/g) and 3,5-dicaffeoylquinic acid (3.12−299.36 µg/g) to be the major components present in the investigated extracts. The ethanol and ethanol/water extracts of both the aerial parts (856.83 and 697.97 µg/g, respectively) and roots (500.43 and 425.59 µg/g, respectively) were found to contain the highest bioactive contents. Antioxidant activity in terms of radical scavenging ability of the extracts ranged from 0.82−45.56 mg TE/g in DPPH assay and from 5.07−104.58 mg TE/g in ABTS assay. Additionally, CUPRAC and FRAP revealed the extracts to display reducing activity in the range of 31.81−151.15 mg TE/g and 14.05−84.32 mg TE/g, respectively. Moreover, the extracts were found to display metal chelating power (7.13−36.17 mg EDTAE/g). The tested extracts were found to inhibit acetylcholinesterase (aerial part: 0.50−2.33 mg GALAE/g; roots: 0.40−2.43 mg GALAE/g), while with the exception of the water extracts, the other extracts showed butyrylcholinesterase inhibition (aerial part: 2.46−5.02 mg GALAE/g; root: 2.93−4.17 mg GALAE/g). Similarly, all extracts except the water extracts demonstrated anti-tyrosinase activity (24.72−61.02 mg KAE/g). Amylase and glucosidase inhibitions were also exhibited by all extracts (0.08−1.37 mmol ACAE/g and 0.23−2.26 mmol ACAE/g, respectively). In general, the enzyme inhibition assays revealed the water extracts to be weak inhibitors of the tested enzymes especially compared to the ethanol and ethanol/water extracts which yielded higher bioactive contents. Overall, this study presented an interesting scope of this species in phytomedicine with preliminary data demonstrating some of the tested extracts to possess high bioactive contents, antioxidant potential and enzyme inhibitory activity. Thus, additional investigations are necessary to confirm their safety in herbal drug applications.