Isolation and lipoxygenase-inhibition studies of phenolic constituents from Ehretia obtusifolia.
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.
Iqbal
Kiran
K
H.E.J. Research Institute of Chemistry, International Center for Chemical Sciences, University of Karachi, Karachi-75270, Pakistan.
Nawaz
Sarfraz Ahmad
SA
Malik
Abdul
A
Riaz
Naheed
N
Mukhtar
Naveen
N
Mohammad
Pir
P
Choudhary
M Iqbal
MI
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*
D016859:Lipoxygenase Inhibitors; D010636:Phenols; D008084:Lipoxygenase