Effect of Alchornea polysaccharide sub-fraction AP-AU1 on NF-κB activation. Human THP-1 monocytes were incubated for 24 h with the indicated concentrations of polysaccharide AP-AU1 (△), AP-AU2 (▲), or 500 ng/ml LPS (positive control, ◆). Alkaline phosphatase activity was analyzed spectrophotometrically (absorbance at 655 nm) in the cell supernatants, as described. Values are the mean ± S.D. of triplicate samples from one experiment, which is representative of two independent experiments.