Identification of the enzyme inhibition effects of metabolites purified from Isatis glauca Aucher ex Boiss. subsp. glauca plant

In this study, inhibition effects of the IG-1 (β-sitosterol-3-O-β-D-glucopyranoside), IG-2 (tetratriacontan), IG-3 (an flavonoid mixture) and IG-4 (luteolin 7-O-glucoside) isolated by chromatographic methods from the dichloromethane:methanol (50:50) extract of the aerial parts of the Isatis glauca Aucher ex Boiss. subsp. glauca were investigated on human carbonic anhydrase I (hCA-I), human carbonic anhydrase I (hCA-II), acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and α-glucosidase enzymes activities. During the extraction process, dichloromethane:methanol (50:50) solvent mixture was added to the dried and ground plant sample was macerated by for 24 hours at room temperature. Thin layer chromatography (TLC) and silica gel column chromatography (SCC) methods were used in the isolation process of the compounds 1H NMR, 13C NMR, 1D and 2D-NMR spectroscopic methods were used to characterize the chemical structures of the isolated compounds. According to the results obtained from biological activity studies, the IC50 values for the BChE of β-sitosterol-3-O-β-D-glucopyranoside (IG-1), tetratriacontan (IG-2) and luteolin 7-O-glucoside (IG-4) are 1.98±0.019, respectively; it was calculated as 1.45±0.010 and 1.58±0.021 µM. It was determined that the compounds have a moderate inhibitory effect compared to the tacrine (IC50: 3.21±0.041 nM) showing more strong inhibition effect on the BChE. In studies performed on carbonic anhydrase enzymes, the compounds, IG-2 (tetratriacontan) and IG-3 (a flovonoid mixture) did not show any inhibition. Luteolin 7-O-glucoside (IG-4), showed the strongest inhibition effect on the hCA-I isoenzyme. However the tested compaunds did not have an inhibitory effect on the α-glycosidase enzyme. 2024, 72 pages Key Words: Isatis glauca Aucher ex Boiss. subsp. glauca, isolation, secondary metabolites, biological activity