The effect of formulations of quercetin, a dose-dependent bioflavonoid, on COX-2 expression and NF-kB
activity in human epithelial MCF-10A cells was investigated. To protect quercetin from exposure to aqueous environment,
four formulations of quercetin-encapsulated liposomes were developed and tested with the MCF-10A cell line.
Phospholipids, cholesterol and Span 60 at a molar ratio of 1:1:1 were used to form liposomes with or without either piperine
or polyethylene glycol 400 (PEG) or alginate as additional ingredients. Overall, the liposomal particles averaged 200
nm in diameter with negative zeta potentials and encapsulation efficiencies of higher than 85%. Using Western blot analysis,
pretreatment of MCF-10A cells with these liposomes containing 7.5 and 15 μM of quercetin were compared with controls.
COX-2 expression induced by 12-O-tetradecanoylphorbol-13-acetate (TPA) was significantly reduced when PEG
was the additional ingredient of the quercetin liposomes. Also, quercetin at 7.5 μM was found to be effective in COX-2
inhibition provided that it was delivered in a liposomal encapsulation with PEG coating. Electrophoretic mobility shift assay
for NF-kB DNA binding activity confirmed the anti-inflammatory activity of quercetin in the nuclei after it was delivered
into the cells by this liposomal formulation. Therefore, some anti-inflammatory activities of quercetin in MCF-10A
cells were influenced by the physicochemical properties of its nanosized liposomes.