2.4.2.3. Measurement of nitrite production
NO production by RAW264.7 cells was determined by measuring the accumulation of nitrite in the culture supernatant using the Griess reagent as previously described (Tewtrakul et al., 2009). After 48 h of incubation, cells generated NO in the medium, the supernatant (100 µl) were collected and reacted with Griess reagent (100 µl). NO production was measured at 570 nm using a microplate reader, PowerWaveX from Bio-Tex Inc. The % inhibition was calculated based on the following equation and IC50 values were determined graphically (n=4):