Saporins are so-called ribosome inactivating proteins (RIPs), due to its N-glycosidase activity, from the seeds of Saponaria officinalis (common name: soapwort).
Immunotoxins consisting of a monoclonal antibody linked to saporin have been developed and evaluated in formal clinical trials in patients with leukaemia and lymphoma in the UK and Germany.
During the past 15 years the research group of Dr David Flavell at Southampton General Hospital in the UK have been investigating various ways of improving the potency and widening the therapeutic window for saporin-based immunotoxins thereby opening up new possibilities for this class of drug.
Most recently saponins (not to be confused with saporin) from Gypsophila paniculata have been shown to significantly augment saporin-based immunotoxins directed against human cancer cells by several orders of magnitude.
In the last 15 years, in research begun by R. G. Wiley of Vanderbilt University, saporin has been used mainly to target specific neuronal populations in lab animals and eliminate them.