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Effects of Esterified Linoleic Acid and Conjugated Linoleic Acid on Pulmonary 15‐Lipoxygenase‐1 Activity
Author(s) -
Cho Hyejung,
Csallany A. Saari
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.5.lb101-b
Subject(s) - lipoxygenase , conjugated linoleic acid , chemistry , nordihydroguaiaretic acid , linoleic acid , substrate (aquarium) , biochemistry , enzyme , metabolite , stereochemistry , fatty acid , biology , ecology
15‐lipoxygenase‐1 (15‐LOX‐1) uses linoleic acid (LA) as substrate and its major metabolite 13(S)‐hydroxyoctadecadienoic acid (13S‐HODE) is involved in the cell proliferation and differentiation. Conjugated linoleic acid (CLA), c9, t11 and t10, c12 are the most biologically active isomers of CLA and have been found to reduce tumor growth in several animal models. Previously we reported that both c9, t11 and t10, c12‐CLA isomers were found to decrease 15‐LOX‐1 activity and 13(S)‐HODE production by dose‐dependent manners (8 to 33 %, and 26 to 57%, respectively). However, t10, c12 was found to be a more effective inhibitor of 15‐LOX‐1 than the c9, t11 isomer. In the present study, 15‐ LOX‐1 activity was measured when esterified LA and esterified c9, t11‐ CLA was used as substrate compared to activities of un‐esterified LA and c9, t11‐CLA. Esterified CLA did not affect 15‐LOX‐1 activity when LA used as substrate. However, when esterified LA used as substrate, 13(S)‐HODE production was increased due to the presence of c9, t11 but not t10, c12‐CLA. Verification of 15‐LOX‐1 activity was tested by nordihydroguaiaretic acid (NDGA), a LOX inhibitor, which decreased 13(S)‐HODE production in a dose‐dependent manner in both esterified LA and c9, t11‐CLA. Esterified c9, t11‐CLA exhibited only 1.2 % activity and esterified LA had 6.6% activity as substrate compared to LA. It has been shown that free and esterified forms of LA and CLA have differing effects on 15‐LOX‐1 activity. (Supported by the MN‐SD Dairy Food Res Ctr)