The saponin-mediated enhanced uptake of targeted saporin-based drugs is strongly dependent on the saponin structure.

Saponins are a group of plant glycosides consisting of a steroid or triterpenoid aglycone to which one or more sugar chains are attached. They exhibit cell membrane-permeabilizing properties and, thus, have been investigated for their therapeutic potential. Recently, at a non-permeabilizing concentration saponinum album from Gypsophila paniculata L.

Combined application of saponin and chimeric toxins drastically enhances the targeted cytotoxicity on tumor cells.

Immunotoxins have to be administered in high doses due to low cytosolic uptake with the consequence of severe side effects. Recently we found that the cytotoxic activity from Agrostemma githago seeds can be attributed to a synergistic toxicity of a triterpenoid saponin and a ribosome-inactivating protein. Here we investigated whether saponins are able to enhance the efficacy of a receptor-specific chimeric toxin consisting of saporin-3, epidermal growth factor and a molecular adapter previously shown to reduce side effects on non-target cells.

Cytotoxic activity of the seeds from Agrostemma githago var. githago.

In our investigations aqueous extracts of the seeds from Agrostemma githago L. proved to be remarkably more cytotoxic in comparison with isolated agrostemmasaponins in equal concentrations. A combination of agrostemmasaponin 1 with a formyl function attached to triterpene position 4 together with agrostin, a ribosome-inactivating protein (RIP type 1; M (r): 27 kDa) which we isolated from the seed material, resulted in a markedly increased cytotoxicity.