Examining the cancer preventing potential of lectin from legumes

A study published in the Journal of Food Science examines the chemical and biological profile of lectin isolated from Japanese red sword beans (Canavalia gladiata; RSBs), a tropical perennial legume, and its potential as a chemopreventive ingredient.

The researchers purified RSB lectin and evaluated the amino acid composition, partial amino acid sequence, blood and carbohydrate specificity, and mitogenic activity. They also evaluated the effects of the lectin on splenic natural killer (NK) cell activity and B16 melanoma cell proliferation in comparison to concanavalin A (Con A), which is a lectin originally extracted from the jack bean and considered to be a potential antihepatoma agent.

The researchers found that RSB lectin showed hemagglutinating activity, specificity for mouse, sheep, and rabbit erythrocytes, and specificity for mannose, glucose, methyl d-mannoside, and thyroglobulin, but not for rhamnose. The results also showed that the amino acid composition and, at least part of, the amino acid sequence of RSB lectin were similar to those of Con A. Additionally, RSB lectin and Con A showed similar levels of heat and protease resistance.

However, RSB lectin exhibited higher mitogenic activity, significantly higher splenic NK cell activity against YAC-1 cells, and significantly stronger effects on the proliferation of B16 melanoma cell lines than Con A. These results suggest that RSB exerts an immunomodulatory effect that is associated with the activation of NK cells and splenic cells.

The researchers concluded that “RSB lectin has the potential to be used in in vitro cancer research.” But they noted that further in vivo studies are needed to investigate the antitumor and immunological effects of RSB lectin when used as a bioactive component, as well as whether the regular consumption of RSB seeds provides a protective effect against cancers through the activation of immune-related cells.

Abstract