Identification and Characterization of Phytohemagglutinins from White Kidney Beans (Phaseolus vulgarisL., var. Beldia) in the Rat Small Intestine

Abstract

Although kidney bean (Phaseolus vulgaris L.) lectin toxicity is widely known, its effects in the gastrointestinal tract require further study. This investigation aimed to identify and characterize phytohemagglutinins (PHAs) in the small intestine and sera of rats following oral challenge with ground white beans. Twenty young, adult male rats were divided randomly into two groups of 10 animals each. The control group underwent gavage with a suspension of 300 mg of rodent pellet flour. The experimental group was administered a 300 mg Beldia bean flour suspension (BBFS). After 10 days of daily treatment, jejunal rinse liquid (JRL) and ileum rinse liquid and secretions, as well as sera, were collected. All biological fluids were screened for lectin reactivity using competitive inhibition ELISA, Ouchterlony double immunodiffusion, and immunoelectrophoresis techniques. The results revealed the presence of immunogenic intraluminal PHAs 3-4 h after the oral intake of the BBFS in the JRLs as well as in the jejunal and ileal secretions; however, no PHA was detectable in the rat sera. Ingestion of raw Beldia beans may lead to interaction between PHAs and the mucosa of the small intestine, potentially resulting in an inflammatory response.

New research highlights: Impact of chronic ingestion of white kidney beans (Phaseolus vulgaris L. var. Beldia) on small-intestinal disaccharidase activity in Wistar rats

“…Since feces reported elsewhere were characterized upon their immuno-hemagglutination reactivities, it is very likely that the phytohemagglutinins (PHAs) were eliminated into the stools, but before day 10 (i.e., material collection day). Our preliminary immunobiochemical studies substantially evidenced the presence of bioactive PHAs in the jejunum and ileum of raw Beldia beans-fed rats [ 30 ]. However in the present study, no lectins were found in the feces and sera of animals on day 10 after 3 h of oral intubation.…”

“…Poor acceptability and digestibility, enzymes inhibitors (e.g., trypsin, chymotrypsin, and α-amylase), and lectins [ 71 ] could be responsible, but there is overwhelming evidence that the latter are at least one of the major causes. Since, an extensive mucosal hyperplasia was revealed along the jejunum and ileum of the rat small intestine [ 29 ], the damage noted on the disaccharidases activities could be attributed largely to the potent mitogens (i.e., growth factors); phytohemagglutinins (PHAs) [ 11 ], which were detected in immunologically intact form in the jejunal lumen, 3 h and 30 min after the orogastric gavage with BBFS [ 30 ].…”

“…The raw Beldia beans demonstrated when orally administered to growing rats for 10 days at dose of 300 mg induced substantial modification of the morphology and physiological functions of the small intestine (i.e., disruption of absorption process) [ 29 ]. Furthermore, serological data revealed effectively the presence of biologically active PHA in the rat jejunal lumen, 3 h and 30 min after oral challenge with 300 mg of Beldia bean flour suspension [ 30 ].…”

Public Health Hazards Associated With Naturally Occurring Toxins in Legume Seeds - Rapid Detection and Characterization of a Lectin From a Korean Cultivated Kidney Bean (Phaseolus Vulgaris L.)

“…nausea, vomiting, and diarrhea) in man [8]. It is generally believed that the lectins in P. vulgaris are the main causative agent responsible of these deleterious effects [9,10]. In this regard, some special attention should be given to the possible occurrence of bioactive lectins in human diets.…”

Neglected and Underutilized Legumes (NULs) Hazards and Probabilistic Risks Associated with Some Selected Dietary Lectins

“…However, legume lectins are particularly resistant to cooking thus, improper cooking, as might occur in street vendered foods or foods cooked in the field, leave substantial amounts of active lectins in the food. It is often argued that legumes are cooked and since lectins are proteins, their biological activities are supposed to be eliminated, but this is not always true because residual lectins have been isolated in many cooked foods [21]. These residual lectins are reckoned as hazards, as they pose risks.…”