Figure 3: Correlation between Papp-Caco-2 and Papp-PAMPA. All data were plotted in the presence and absence of a proton gradient (apical or donor pH, 6.0 or 7.4; basolateral or accepter pH, 7.4). Genistein in the presence (■) and absence (□) of a proton gradient, DHG in the presence (▲) and absence (△) of a proton gradient,daidzein in the presence (●) and absence (○) of a proton gradient, DHD in the presence (○) and absence (◇) of a proton gradient. DHG, dihydrogenistein; DHD, dihydrodaidzein; PAMPA, artificial membrane permeation assay.