Cytotoxic Activity of a Black Bean (Phaseolus vulgaris L.) Extract and its Flavonoid Fraction in Both In Vitro and In Vivo Models of Lymphoma

Black bean (Phaseolus vulgaris L.) is a very common legume seed in Mexican diet. Flavonoids and crude extracts from different plants have been reported as effective agents for chemoprevention and cytotoxicity in several cancer cell lines. We investigated the effects of black bean hulls extract (BBE) and its flavonoid fraction (FF) on lymphoma cells. BBE and FF were characterized by high-performance liquid chromatography. Viability and flow cytometry assays were carried out. Finally, a mouse model was generated to test the in vivo effect of both fractions. Both BBE and FF inhibited cell proliferation in a dose-dependent way. In addition, cells underwent apoptosis, and the cellular population at S-phase increased after exposure to these fractions. Furthermore, mice treated with BBE or FF increased the overall survival by 5 or 6 days, respectively, in comparison with a placebo group (p = 0.056). BBE and FF had cytotoxic action by driving OCI-Ly7 cells into apoptosis as well as blocking progression to G2/M phase. In addition, BBE and FF treatments were effective in xenograft models.