The aim of this study was to determine whether a lectin fraction (LF) from Tepary bean seeds (Phaseolus acutifolius) exhibits apoptotic induction on colon cancer cells and its in vivo effect on tumorogenesis in rats. Median lethal concentration (0.402 mg protein/mL) on HT‐29 cells caused a significant increase in caspase 3 activity, an overexpression of caspase 3 (35%) and caspase 9 (78%) and a 36.6% apoptosis increase determined by flow cytometry. Colon cancer was induced on male Sprague Dawley rats treated for 8 weeks with 1,2‐dimethylhydrazine (DMH) (40 mg/body weight kg) and a subsequent administration of 50 mg of LF/body weight kg for 6 weeks. The LF provoked a decrease in food consumption and body weight of rats with a partial recovery at the end of the experiment. Histopathological analysis showed that LF decreased the incidence of early stages tumors in a 53% but no effect was observed on high grade carcinogenesis. The results show that LF induces apoptosis in colon cancer and it has inhibitory effect on early tumorogenesis.Founding: CONACYT Ciencia Básica (82349)

Our previous studies showed that a lectin fraction from Tepary bean exhibits low toxicity but antinutritional effects in rats. The aim of this study was to determine the in vivo effect of a lectin‐protease inhibitor fraction (LIP‐60). Three administration schedules were tested for intragastric administered LIP‐60 in Sprague Dawley rats: 1) acute toxicity was determined using a single dose of LIP‐60 per group (10, 100, 1000 mg/body weight kg), 2) for the subchronic toxicity a daily LIP‐60 dose (100 mg/body weight kg) was administered for 28 days, 3) for the long‐term scheme, LIP‐60 (100 mg/body weight kg) was administered twice a week for 6 weeks. The animals were sacrificed to obtain blood samples in order to determine markers for renal, hepatic and pancreatic damage and also the nutritional status. Acute toxicity did not show adverse effects, only the highest dose provoked lethargy for the first 12 h. Subchronic test showed piloerection, yellow hair pigmentation, diarrhea, abdominal distention, irritability, partial food intake decrease and stationary body weight gain with a 10% decrement, blood markers for toxicity or nutritional status did not show significant alterations. The long‐term scheme did not show adverse effects neither before sacrifice nor blood markers. Our results suggest that LIP‐60 present a low toxicological profile, further studies will focus on effects on gastrointestinal tract and against colon cancer. Founding: CONACYT FOMIX (QRO‐2011‐C02‐175340)

Studies from our group have shown that lectins and protease inhibitors (PIs ) of Tepary beans have individual effects on colon cancer cells. In order to know the in vivo effects of a combined fraction of lectins and protease inhibitor (LIP‐60), alterations in the hematopoietic system were determined. Sprague Dawley rats of 3 weeks old were administered intragastrically with LIP‐60 (100 mg/kg body weight) for 28 days. Blood samples were obtained on 0, 1, 3, 9, 14, 19 and 24 days, animals were sacrificed at day 30 and spleen, thymus and femur bone marrow were obtained for histopathological analysis. Body weight and food consumption decreased were observed respect to control group. Complete blood count showed decrease in lymphocytes while granulocytes increased, suggesting allergic process. Histopathological analyzes showed reduced white pulp of the spleen, related with an increase in the release of mature leukocytes. The results suggest that LIP‐60 provoke allergy‐like response. Grant Funding Source: CONACYT FOMIX (QRO‐2011‐C02‐175340)