Phaseolus acutifolius (Tepary bean) lectins have been studied as cytotoxic molecules on colon cancer cells. The toxicological profile of a Tepary bean lectin fraction (TBLF) has shown low toxicity in experimental animals; exhibiting anti-nutritional effects such as a reduction in body weight gain and a decrease in food intake when using a dose of 50 mg/kg on alternate days for six weeks. Taking this information into account, the focus of this work was to evaluate the effect of the TBLF on colon cancer using 1,2-dimethylhydrazine (DMH) or azoxy-methane/dextran sodium sulfate (AOM/DSS) as colon cancer inductors. Rats were treated with DMH or AOM/DSS and then administered with TBFL (50 mg/kg) for six weeks. TBLF significantly decreased early tumorigenesis triggered by DMH by 70%, but without any evidence of an apoptotic effect. In an independent experiment, AOM/DSS was used to generate aberrant cryptic foci, which decreased by 50% after TBLF treatment. TBLF exhibited antiproliferative and proapoptotic effects related to a decrease of the signal transduction pathway protein Akt in its activated form and an increase of caspase 3 activity, but not to p53 activation. Further studies will deepen our knowledge of specific apoptosis pathways and cellular stress processes such as oxidative damage.

Lectins can specifically recognize carbohydrates of cell membranes and some of them exhibit anticancer properties. In a previous work, we identified a cytotoxic lectin from tepary bean with differential antiproliferative effect on normal and transformed fibroblasts. The goal of the present work was to evaluate the effect of a concentrated tepary bean lectin fraction (TBLF) on human cancer cell lines growth. TBLF was obtained by molecular weight exclusion and ion exchange chromatography and it was tested on breast cancer cells (MCF‐7 and ZR‐75), cervix cancer cells (HeLa, SiHa and C33A) and colon cancer cells (CaCo2). All cell lines showed a cytotoxic effect, after 72 h of treatment. Inhibitory (IC50) and lethal (LC50) concentrations were calculated for each cell line. The most sensible cells were colon cancer cells with IC50 of 0.119 and LC50 of 3.0 μg protein/mL. CaCo2 and normal intestinal cells from rat illeon (IEC‐18), included as normal counterpart, were also tested at 24 h, LC50 did not change for CaCo2 but IC50 was of 0.563 μg protein/mL; for IEC‐18, IC50 and LC50 were of 0.993 and 7.95 μg protein/mL, respectively. Our results show that TBLF is able to recognize selectively different types of cancer cells, more over between normal and cancer cells. Current studies are focusing on TBLF mechanism action and on in vivo studies against colon cancer.

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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)

Angiogenesis, the formation of new blood vessels, underlies tissue development and repair. Some medicinal plant-derived compounds can modulate the angiogenic response. Heliopsis longipes, a Mexican medicinal plant, is widely used because of its effects on pain and inflammation. The main bioactive phytochemicals from H. longipes roots are alkamides, where affinin is the most abundant. Scientific studies show various medical effects of organic extracts of H. longipes roots and affinin that share some molecular pathways with the angiogenesis process, with the vasodilation mechanism of action being the most recent. This study investigates whether pure affinin and the ethanolic extract from Heliopsis longipes roots (HLEE) promote angiogenesis. Using the aortic ring rat assay (ex vivo method) and the direct in vivo angiogenesis assay, where angioreactors were implanted in CD1 female mice, showed that affinin and the HLEE increased vascular growth in a dose-dependent manner in both bioassays. This is the first study showing the proangiogenic effect of H. longipes. Further studies should focus on the mechanism of action and its possible therapeutic use in diseases characterized by insufficient angiogenesis.