Figure 2: Effects of solvent fractions of Zanthoxylum rhetsa extract on nitric oxide production in lipopolysaccharide-stimulated mouse RAW 264.7 macrophages. Nitric oxide production after incubation with indicated concentrations of fractions (methanol, butanol, ethyl acetate, chloroform, and hexane) for 24 h was quantified using Griess reagent. Nitric oxide levels are expressed in μM, and the values shown in the graphs are mean ± standard deviation obtained from triplicate experiments.^###P < 0.001, lipopolysaccharide-treated group versus control; **P < 0.01 and *P < 0.05, significant difference from the lipopolysaccharide-treated group