title: Isolation and lipoxygenase-inhibition studies of phenolic constituents from Ehretia obtusifolia.
abstract: The phenolic compounds methyl 2-O-feruloyl-1a-O-vanillactate (1), caffeic anhydride (2), and trans 4-hydroxycyclohexyl-2-O-p-coumaroyl beta-D-glucopyranoside (3) have been isolated from the AcOEt-soluble fraction of Ehretia obtusifolia, along with methyl rosmarinate (4) and rosmarinic acid (5), which are reported for the first time from this species. Their structures were determined by means of 1D- and 2D-NMR techniques. Compounds 1-5 inhibited lipoxygenase in a concentration-dependent manner, with Ki values ranging from 0.85-57.6 microM. Compounds 1, 2, 4, and 5 showed noncompetitive inhibition, whereas 3 was found to be an uncompetitive inhibitor of lipoxygenase.
authors.affiliation: H.E.J. Research Institute of Chemistry, International Center for Chemical Sciences, University of Karachi, Karachi-75270, Pakistan.
authors.forename: Kiran
authors.initials: K
authors.lastname: Iqbal
authors.forename: Sarfraz Ahmad
authors.initials: SA
authors.lastname: Nawaz
authors.forename: Abdul
authors.initials: A
authors.lastname: Malik
authors.forename: Naheed
authors.initials: N
authors.lastname: Riaz
authors.forename: Naveen
authors.initials: N
authors.lastname: Mukhtar
authors.forename: Pir
authors.initials: P
authors.lastname: Mohammad
authors.forename: M Iqbal
authors.initials: MI
authors.lastname: Choudhary
mesh_terms: D028082:Boraginaceae / Q000737:chemistry*; D004305:Dose-Response Relationship, Drug; D008084:Lipoxygenase / Q000378:metabolism*; D016859:Lipoxygenase Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D010636:Phenols / Q000737:chemistry* / Q000494:pharmacology*
chemical_list: D016859:Lipoxygenase Inhibitors; D010636:Phenols; D008084:Lipoxygenase