Lutein is a competitive inhibitor of cytosolic Ca²+-dependent phospholipase A₂.
OBJECTIVE
We have investigated the effect of lutein on phospholipase A₂ (PLA₂) isozymes.


METHODS
We measured arachidonic acid release in [³H]arachidonic acid-labelled Raw 264.7 cells and PLA₂ activity using 1-palmitoyl-2-[¹⁴C]arachidonyl phosphatidylcholine ([¹⁴C]AA-PC) and 10-pyrene phosphatidylcholine in vitro.


RESULTS
Lutein suppressed the release of arachidonic acid and inhibited Raw 264.7 cell-derived cytosolic Ca²+-dependent PLA₂ (cPLA₂-induced hydrolysis of [¹⁴C]AA-PC in a dose- and time-dependent manner. In contrast, lutein did not affect secretory Ca²+-dependent PLA₂ (sPLA₂)-induced hydrolysis of [¹⁴C]AA-PC. A Dixon plot showed that the inhibition by lutein on cPLA₂ appeared to be competitive with an inhibition constant, K(i) , of 13.6 µm.


CONCLUSIONS
We suggest that lutein acted as a competitive inhibitor of cPLA₂ but did not affect sPLA₂.
College of Pharmacy, Chung-Ang University, 221 Huksuk-dong, Dongjak-gu, Seoul 156-756, Korea.
Ho Sun
HS
Song
Hee Rae
HR
Kim
Myung Cheul
MC
Kim
Yeon Hee
YH
Hwang
Sang Soo
SS
Sim
D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology; D016718:Arachidonic Acid / Q000378:metabolism; D001798:Blood Proteins / Q000378:metabolism / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D003600:Cytosol / Q000201:enzymology; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000378:metabolism; D014975:Lutein / Q000494:pharmacology*; D051379:Mice; D010713:Phosphatidylcholines / Q000378:metabolism; D054467:Phospholipases A2 / Q000378:metabolism*
D000894:Anti-Inflammatory Agents, Non-Steroidal; D001798:Blood Proteins; D007527:Isoenzymes; C400481:PLIalpha; D010713:Phosphatidylcholines; D016718:Arachidonic Acid; D054467:Phospholipases A2; D002118:Calcium; D014975:Lutein