Roland De Wilde

Inhibitory action of spray dried blood plasma and whole egg powder on lectins in extracts of several legume seeds : a qualitative approach

Samples of seeds from eight legume species and Triticum vulgaris grains were extracted with buffer and lectin activity in the extracts was determined in haemagglutination experiments using normal or Pronase-treated rabbit erythrocytes. The effect of the addition of spray dried porcine and bovine plasma powder, whole egg powder, galactosides, whey powder and specific inhibitors (eg mannose, galactose, N-acetyl galactosamine, fetuin) on haemagglutination activity (HA) was determined. Plasma powders were potent inhibitors of HA in extracts of Pisum sativum, Vicia faba, Vicia sativa, Lens culinaris and Phaseolus vulgaris. HA in extracts of Lupinus sp and Phaseolus vulgaris was efficiently decreased by whole egg powder, while the lectin of Glycine max could only be inhibited by addition of galactosides, whole and defatted milk powder and whey powder. Inhibitors (plasma and whole egg powder and fetuin) were subjected to SDS-PAGE and Western blotting and blots were incubated with biotinylated lectins, except for Lupinus lectin. Results of the HA experiments were confirmed: lectins which were not influenced by inhibitory compounds in HA experiments also showed no binding with proteins of the blotted inhibitor. There were strong indications that lectins were not bound to the albumin fraction of the plasma powders. Results are discussed in view of future in vivo experiments.