Figure 3
Dose response curves for batches #9 (blue, squares), #3 (red, circles) and andrographolide (green, triangles). IC50 of pure andrographolide: 21.9 μM (n = 3; 95% confidence interval: 18.1 - 26.5 μM), extract #3: 16.4 μM (n = 3; 95% confidence interval: 13.8 - 18.8 μM), extract #9: 18.7 μM (n = 3; 95% confidence interval: 14.9 - 23.4 μM). The concentrations have been normalized to concentration of andrographolide in the batches. The data were fitted with a log (inhibitor) vs. normalized response with variable slope model. The IC50 was calculated from the fitted curve. F-test indicated that all data could be equally fitted with a single curve with IC50 = 18.5 μM (p = 0.51; 95% confidence interval: 16.7 to 20.7 μM).