Macrophages and microglia are thought to account for initial
disease progression in acute
myocardial infarction and
acute ischemic stroke. Before our study, the inhibitory effects of
naringenin, a
flavonoid, on
lipopolysaccharide (LPS)-induced
inflammation in macrophages and microglia have not been fully reported and compared. We hypothesized that
naringenin can effectively inhibit LPS-induced
inflammation of macrophages and microglia at different concentrations, the range of which is broader, with the lowest concentration more easily achieved in macrophages. In this study, we compared the anti-inflammatory effects of
naringenin on LPS-stimulated RAW 274.6 macrophages and BV2 microglia and the suppression effects of
naringenin and
vitamin C (a well-known
anti-inflammatory agent) on LPS-induced
nitrite production. The results show that macrophages could maintain cell viability at higher
naringenin concentrations and were more easily activated by LPS in comparison to microglia (200 vs 100 μmol/L; 0.1 vs 1 μg/mL). Under LPS (1 μg/mL) stimulation in both cell types,
naringenin (up to 200 μmol/L in macrophages and 100 μmol/L in microglia) inhibited
nitrite production and
inducible nitric oxide synthase and
cyclooxygenase-2 expression in a dose-dependent manner. The range of
naringenin concentrations for inhibition was broader, and the lowest concentration was more easily achieved in macrophages; the lowest effective concentrations of
naringenin to achieve constant suppression effect were 50 μmol/L in macrophages and 100 μmol/L in microglia, respectively.
Vitamin C (100 μmol/L), compared with
naringenin (100 μmol/L), had less and no suppression effect on LPS (1 μg/mL)-induced
nitrite production in macrophages and microglia, respectively. In conclusion,
naringenin more effectively inhibits the LPS-induced inflammatory status, including
nitrite production and
inducible nitric oxide synthase and
cyclooxygenase-2 expression, in macrophages than in microglia. The findings of the present study suggest that consumption of
naringenin-containing
flavonoids might be beneficial to the cardiovascular and cerebrovascular inflammatory process.