Effects of pelargonidin-3-O-glucoside and its metabolites on lipopolysaccharide-stimulated cytokine production by THP-1 monocytes and macrophages.

Epidemiological evidence suggests cardioprotective effects of anthocyanin consumption. This study examined the predominant strawberry anthocyanin, pelargonidin-3-O-glucoside (Pg-3-glc), and three of its plasma metabolites (protocatechuic acid [PCA], 4-hydroxybenzoic acid, and phloroglucinaldehyde [PGA]) for effects on the production of selected cytokines by lipopolysaccharide-stimulated THP-1 monocytes and macrophages. Concentrations of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6, IL-8 and IL-10 were determined using a cytometric bead array kit. PCA at 0.31, 1.25 and 20 μM and PGA at 5 and 20 μM decreased the concentration of IL-6 in the monocyte cultures, but there were no effects on TNF-α, IL-1β, IL-8 and IL-10 and there were no effects of the other compounds. In the macrophage cultures, PGA at 20 μM decreased the concentrations of IL-6 and IL-10, but there was no effect on TNF-α, IL-1β and IL-8 and there were no effects of the other compounds. In conclusion, while the effects of PGA were only observed at the higher, supraphysiological concentration and are thus considered of limited physiological relevance overall, the anti-inflammatory properties of PCA were observed at both the lower, physiologically relevant, and the higher concentrations; however, effects were modest and limited to IL-6 and monocytes. These preliminary data suggest potential for physiologically attainable PCA concentrations to modulate IL-6 production by monocytes.