In vitro acetylcholinesterase, tyrosinase inhibitory potentials of secondary metabolites from Euphorbia schimperiana and Euphorbia balsamifera .

Acetylcholinesterase, tyrosinase, and α -glucosidase inhibition activities of Euphorbia schimperiana and  Euphorbia balsamifera extracts, fractions, and available pure compounds were evaluated for the first time. Acetylcholinesterase assay revealed a significant inhibitory activity of E. balsamifera total extract and n -hexane fraction with 47.7% and 43.3%, respectively, compared to the reference drug, which was 75%. The n -butanol fraction demonstrated tyrosinase inhibitory activity for E. balsamifera and E. schimperiana with 36.7% and 29.7%, respectively, compared to 60% for the reference drug. Quercetin-3- O-α -glucuronide, quercetin-3- O-β-D -glucuronide-methyl ester, quercetin-3- O-α-L -rhamnoside, 3,3'-di- O -methyl ellagic acid, 3,3' -di-O -methyl-ellagic acid-4- β-D -xylopyranoside, and 4- O -ethyl gallic acid were identified from E. schimperiana while quercetin-3- O -glucopyranoside and isoorientin were determined from E. balsamifera . The AChE inhibitory effect of pure compounds exhibited promising activity, where 4- O -ethylgallic acid demonstrated 51.1%, while the highest tyrosinase inhibition was demonstrated by isoorientin with 50.6% compared to the reference drug (60%). Finally, a molecular docking study was performed for the most promising AChE and tyrosinase inhibitors. The extracts, fractions, and isolated compounds showed no α-glucosidase inhibitory activity.