2.5. Determination of PGE2 and NO secretion
The anti-inflammatory activity of citrus samples was evaluated,
based on their inhibitory effect on the PGE2 and NO secretion in
LPS-activated RAW 264.7 macrophages. In brief, 6 105 RAW
264.7 cells were seeded into each well of a 24-well culture plate
and incubated for 24 h. After they were washed three times with
PBS, adherent cells were incubated with the peel extract (dissolved
in DMEM), with or without LPS (1 lg/ml). After incubation for a
further 20 h, the medium was collected for the PGE2 and NO assay,while cell viability was evaluated using the MTT method. The PGE2
concentration in the medium was measured by a commercial ELISA
kit (Cayman Chemical, Ann Arbor, MI, USA) and the NO concentration
was measured by use of the Griess reagent.