Fig. 2

Subfractions of E. citriodora leaf essential oils inhibited NO generation. (a) RAW264.7 macrophages were treated for 0.5 h with 100 μg/ml Fractions A, B, C, D, E, F, G and H, followed by incubation with or without 1 μg/ml LPS for 24 h. NO production in the culture medium was measured by the Griess reaction. b RAW264.7 macrophages were treated for 0.5 h with 12.5 μg/ml, 25 μg/ml, 50 μg/ml or 100 μg/ml Fractions D, E, F or G, followed by incubation with or without 1 μg/ml LPS for 24 h. NO production in the culture medium was measured by the Griess reaction. c RAW264.7 macrophages were incubated for 24 h with or without Fractions F and G. Cell viability was measured by the Alamar Blue assay. Data are expressed as means ± SD of three independent experiments. *P < 0.05 compared to LPS alone. (n = 3)