Effect of Alchornea polysaccharide fractions on murine macrophage nitric oxide production. Murine J774.A1 macrophages were incubated for 24 h with the indicated concentrations of polysaccharide fractions AP-AU (○), AP-NU(□), AP-AB (●), AP-NB (■), AP-AU1 (△), AP-AU2 (▲), or 500 ng/ml LPS (panel A, ◆). NO production was quantified by measuring nitrite in the cell-free supernatants. Values are the mean ± S.D. of triplicate samples from one experiment, which is representative of two independent experiments.