Inhibitory effect on soybean lipoxygenase and docking studies of some secondary metabolites, isolated from Origanum vulgare L. ssp. hirtum

Figures & data

Figure 1 Chemical structures of the investigated compounds: caffeic acid (1), rosmarinic acid (2), lithospermic acid B (3), 12-hydroxyjasmonic acid 12-O-β-glucoside (4), and p-menth-3-ene-1,2-diol 1-O-β-glucopyranoside (5).

Table I.  Inhibition of soybean lipoxygenase in vitro IC₅₀ (mM), calculated binding energy for the highest ranked docking solution and calculated Log P value of the docked conformers.

Compounds	IC50 (mM)^a	Binding energy (Kcal/mol)	Log P
1	0.60 ± 0.015	− 9.70	1.56
2	1.15 ± 0.09	− 4.93	2.83
3	0.10 ± 0.006	− 19.52	4.11
4	0.56 ± 0.003	− 10.45	− 2.62
5	0.36 ± 0.002	− 12.57	− 1.38
quercetin	0.18 ± 0.003	–	–

^a Means ± s.d. of at least triplicate determinations

Figure 2 Chemical structure of 13-HPOD [9Z,11E-13(S)-hydroxyperoxy-9,11-octadecadienoic acid].

Figure 3 Conformational comparison between X-ray structure of 13-HPOD (colored by atom type) (PDB IK3) and predicted (colored yellow) by GLUE. Iron atom is illustrated as a sphere (colored magenta). Colour plate can be viewed in the online version.

Figure 4 Docked orientations of a. caffeic acid (1) b. rosmarinic acid (2) c. lithospermic acid B (3) d. 12-hydroxyjasmonic acid 12-O-β-glucopyranoside (4) and e. p-menth-3-ene-1,2-diol 1-O-β-glucopyranoside (5) (illustrated as a ball-and-stick model colored by atom type) with additional depiction of selected amino acid residues of soybean lipoxygenase (PDB IK3) as well as 13-HPOD (drawn as sticks). Hydrogen bonds and polar interactions are shown as dotted lines. White colored circles highlight double bond position of the compounds. Iron atom is illustrated as a sphere (colored magenta). Coloured plate can be viewed in the online version.