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Mouse macrophage cell line (RAW 264.7) was obtained from Bioresource Collection and Research Center (BCRC 60001) and cultured at 37C in Dulbecco’s Modified Eagle’s Medium (DMEM) supplemented with 10% fetal bovine serum (FBS; Gibco), 4.5 g/l glucose, 4 mm glutamine, penicillin (100 units/ml), and streptomycin (100 mg/ml) in a humidified atmosphere in a 5% CO2 incubator. The cells were treated with 10, 25, and 50 mm natural products (4-Hydroxy-6-methyl-2-pyrone) in the presence of 1 mg/ml LPS (Sigma Aldrich) for 20 h. The concentration of NO in culture supernatants was determined as nitrite, a major stable product of NO, by Griess reagent assay, and cell viabilities were determined using the MTT assay. Levels of IL-6 production were measured in cell culture supernatants with a Mouse IL-6 ELISA Ready-SET-Go ELISA kit (eBiosciencee) according to the manufacturer’s recommendations and quantified with a microplate reader (m-Quant, Bio-Tek Instruments Inc).