Figure 3.

Effects of lupeol cinnamate (compound 3) (A) and betulinic acid (compound 5) (B) on nitrite levels produced in the cell medium of J774A.1 murine macrophages in response to lipopolysaccharide (LPS; 1 μg/mL) for 24 h. Compounds 3 and 5 were given to the cell media 30 min before LPS insult. Results are reported as percentage of nitrites and expressed as mean ± SEM of three or four independent experiments. § p < 0.0001 vs. control (cells without LPS); * p < 0.05, ** p < 0.01, and **** p < 0.0001 vs. LPS as assessed by one-way ANOVA, followed by Dunnett’s multiple comparisons test. IC₅₀ curves (concentration of the compounds that caused the 50% inhibition of nitrite production) for lupeol cinnamate (compound 3) (C) and betulinic acid (compound 5) (D) were calculated by non-linear regression analysis using the sigmoid concentration–response curve.