In vitro permeability of saponins and sapogenins from seed extracts by the parallel artificial membrane permeability assay (PAMPA): effect of in vitro gastrointestinal digestion.

The permeability of saponins and sapogenins from fenugreek and quinoa extracts, as well as dioscin and diosgenin, was evaluated by the parallel artificial membrane permeability assay (PAMPA). The effect of the digestion process on permeability was determined, with previous development of a gastrointestinal process coupled to PAMPA. Saponins from both seeds displayed a moderate-to-poor permeability (>1 x 10(-6) cm/s), although the digestion enhanced their permeability values in the order of 10(-5) cm/s (p < 0.001). Sapogenins exhibited a similar permeability to that of saponins, although the digestion enhanced the permeability of sapogenins from quinoa (1.14 +/- 0.47 x 10(-5) cm/s) but not from fenugreek (2.33 +/- 0.99 x 10(-6) cm/s). An overall positive impact of coexisting lipids on the permeability was evidenced. PAMPA is shown as a useful, rapid, and easy tool for assessing the permeability of bioactive compounds from complex matrices, with the previous gastrointestinal process being a relevant step.