The in vitro effect of seed extracts (lectins) on tumor cells.

Specificity of action of antitumor agents is, of course, an ideal property for chemotherapeutic substances to be used in the treatment of neo plasms. In general, specificity in biological action is associated with macromolecular substances such as, for example, immune globulins; antigenic sub stances such as bacterial polysaccharides; or en zymes. Boyd (1) and others have demonstrated a high order of specificity of certain seed extracts (lectins) in agglutinating human erythrocytes of one or another major or minor blood group. This chance specificity of action of lectins on human erythrocytes stimulated the senior author to initi ate a study of the possible effects of these natural ly occurring substances on animal tumor cells. The first results of this program were published in 1953 (8). Investigations of naturally occurring sub stances for their possible action against tumors are numerous. Although plant seeds have been so in vestigated, their inclusion in an array of extracts of plant parts has been so infrequent as to appear incidental. An intentional, orderly attempt to study seeds from this standpoint was made, to the best of our knowledge, first in our laboratory (8) and subsequently by others (6). Plant seeds offer certain advantages in screening for naturally oc cunning antitumor agents in that (a) they are