title: α-Glucosidase activity of oleanolic acid and its oxidative metabolites: DFT and Docking studies.
abstract: A natural pentacyclic triterpenoid oleanolic acid 1 and its biotransformed metabolites 2-3 are potential α-glucosidase inhibitors. To elucidate the inhibitory mechanism of compounds 1, 2 and 3 against α-glucosidase, we calculated (i) their electronic and optical properties using DFT and TD-DFT at the B3LYP/6-31G(d) level in gas and IEF-PCM solvent; and (ii) their binding energies to α-glucosidase via docking study. DFT results showed that the α-glucosidase inhibtion is mainly depend on the polarity parameters of the studied compounds. Docking results revealed that the activity increased with binding energies (i.e. the stability of ligand-receptor complex). The specroscopic data of oleanolic acid 1 and its metabolites 2 and 3 are well predicetd for 13C NMR chemical shifts (R2=99%) and 1H NMR chemical shifts (R2=90%); and for (ii) UV/vis spectra. The assignments and interpretation of NMR chemical shifts and bathochromic shift of λMAX absorption bands are discussed.
authors.forename: El Hassane
authors.initials: el H
authors.lastname: Anouar
authors.forename: Nur Shahidatul Shida
authors.initials: NS
authors.lastname: Zakaria
authors.forename: Ali
authors.initials: A
authors.lastname: Alsalme
authors.affiliation: Atta-ur-Rahman Institute for Natural Product Discovery (AuRIns), Universiti Teknologi MARA Campus Puncak Alam, 42300 Bandar Puncak Alam, Selangor D.E, Malaysia. anouarelhassane@yahoo.fr.
authors.forename: Syed Adnan Ali
authors.initials: SA
authors.lastname: Shah
mesh_terms: D004789:Enzyme Activation / Q000187:drug effects; D065089:Glycoside Hydrolase Inhibitors / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology*; D006801:Humans; D008968:Molecular Conformation; D062105:Molecular Docking Simulation; D009828:Oleanolic Acid / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology*; D010084:Oxidation-Reduction; D011789:Quantum Theory; D000520:alpha-Glucosidases / Q000737:chemistry / Q000378:metabolism*
chemical_list: D065089:Glycoside Hydrolase Inhibitors; D009828:Oleanolic Acid; D000520:alpha-Glucosidases