Effect of ingested winged bean lectin on gastrointestinal function in the rat.

Abstract

SummaryThe present study was undertaken to provide further evid ence for mechanisms proposed for the toxicity of ingested winged bean lectin in animals: to determine its effect on activities of some hydrolases localized in the brush border membrane of the small intestine. An adaptive increase in sucrase activity of rats given a high-sucrose diet (HSD) was restrained by the addition to HSD of a lectin fraction (WBLF) isolated from raw winged beans but not by that of heated WBLF or soybean trypsin inhibitor. Restraining effects of WBLF added to HSD on time course changes in activities of sucrase, alkaline phosphatase and leucine aminopeptidase of rats after giving HSD were similar to those of concanavalin A, which had been observed in the previous study. These results substantiate that the mechanism of the toxicity of ingested winged bean lectin involves its binding to the luminal surface of the small intestine and in turn disturbing the functional formation of the brush border membrane.

The interaction between plant lectins and the small intestinal epithelium: A primary cause of intestinal disturbance

“…These changes in enzyme activity occurred with lectin concentrations which were able to precipitate enzymes in vitro. Inhibitory sugars could prevent the disturbance of the enzyme activity, which suggests that the effect is due to the binding of lectins to specific carbohydrate structures (13,26) injury of the cytoskeleton of enterocytes by WGA and ConA. SBA added to a human colon carcinoma cell lina (Caco-2), had an effect on the cytoskeleton of these cells, consisting of a conversion of F-actin into G-actin (9).…”