Effects of Dietary Phenolic Compounds on Cytokine and Antioxidant Production by A549 Cells

Levels of inflammatory cytokines are raised in chronic obstructive pulmonary disease (COPD). A diet rich in antioxidant vitamins may protect against the development of COPD. This study examined the effects of phenolic compounds and food sources on cytokine and antioxidant production by A549 cells. The effects of the following phenolic compounds on basal and interleukin (IL)-1-stimulated release of IL-8, IL-6, and reduced glutathione (GSH) were examined: resveratrol; Bouvrage, a commercially available raspberry juice (Ella Drinks Ltd., Alloa, Clacksmannanshire, UK); and quercetin 3'-sulfate. Purification of the raspberry juice by high-performance liquid chromatography gave three fractions: Fraction 1 contained phenolic acid and vitamin C, Fraction 2 contained flavonoids and ellagic acid, and Fraction 3 contained anthocyanins and ellagitannins. IL-8 production was increased in the presence of IL-1 (165 vs. 6,011 pg/mL, P < .0001). None of the compounds tested had any significant effect on GSH. Resveratrol at concentrations > or =50 micromol/mL significantly inhibited IL-8 and IL-6 production. Similar findings were made with raspberry juice at concentrations > or =25 microL/mL, and Fractions 1 and 3 were best able to inhibit IL-8 production. Quercetin 3'-sulfate, at 25 micromol/mL, inhibited IL-8 and IL-6 production. The changes observed in IL-8 were paralleled by changes in tumor necrosis factor-alpha. Thus, phenolic compounds can significantly alter cytokine and antioxidant production.