α-Glucosidase, butyrylcholinesterase and acetylcholinesterase inhibitory activities of phenolic compounds from Carthamus tinctorius L. flowers: In silico and in vitro studies.

Chemical investigation of Carthamus tinctorius L. flowers resulted in isolation of seven metabolites that were identified as; p -Hydroxybenzoic acid ( 1 ), trans hydroxy cinnamic acid ( 2 ), kaempferol-6-C-glucoside ( 3 ), astragalin ( 4 ), cartormin ( 5 ), kaempferol-3- O -rutinoside ( 6 ), and kaempferol-3- O -sophoroside ( 7 ). Virtual screening of the isolated compounds against human intestinal α-glucosidase, acetylcholinesterase, and butyrylcholinesterase was carried out. Additionally, the antioxidant activity of the bioactive compounds was assessed. Compounds 1 and 5 exhibited moderate binding affinities to acetylcholinesterase (binding energy -5.33 and -4.18 kcal/mol, respectively), compared to donepezil (-83.33kcal/mol). Compounds 1 - 7 demonstrated weak affinity to butyrylcholinesterase. Compounds 2 and 4 displayed moderate binding affinity to human intestinal α-glucosidase,compared to Acarbose (reference compound), meanwhile compound 2 exhibited lower affinity. Molecular dynamic studies revealed that compound 4 formed a stable complex with the binding site throughout a 100 ns simulation period. The in-vitro results were consistent with the virtual experimental results, as compounds 1 and 5 showed mild inhibitory effects on acetylcholinesterase (IC 50 s 150.6 and 168.7 µM, respectively). Compound 4 exhibited moderate α-glucosidase inhibition with an IC 50 of 93.71 µM. The bioactive compounds also demonstrated notable antioxidant activity in ABTS [2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)], ORAC (oxygen radical-absorbance capacity), and metal chelation assays, suggesting their potential in improving dementia in Alzheimer's disease (AD) and mitigating hyperglycemia.