Hyperoside and rutin of Nelumbo nucifera induce mitochondrial apoptosis through a caspase-dependent mechanism in HT-29 human colon cancer cells

The present study demonstrates the mechanism of 2 flavonol glycosides, hyperoside and rutin, in the induction of apoptosis in HT-29 human colon cancer cells through the bioactivity-guided fractionation and isolation method. The chemical structure of hyperoside and rutin, isolated from the roots of Nelumbo nucifera, were established using extensive 1- and 2-dimensional nuclear magnetic resonance experiments and absolute high resolution fast-atom bombardment mass spectrometry, ultraviolet-visible and Fourier transform infrared spectroscopy spectral analytical methods. The treatment of HT-29 colon cancer cells with hyperoside and rutin significantly decreased cell viability in a dose-dependent manner. The concomitant activation of the mitochondria-dependent apoptotic pathway of hyperoside and rutin occurred via modulation of Bcl-2-associated X protein and B-cell lymphoma 2 expression, resulting in the activation of cleaved caspases-3, -8 and -9 and cleaved poly-(ADP-ribose) polymerase. The findings of the present study indicate that hyperoside and rutin induce apoptosis in HT-29 human colon cancer cells, and that this phenomenon is mediated via the death receptor-mediated and mitochondria-mediated apoptotic pathways. These results suggest that hyperoside and rutin may be useful in the development of a colon cancer therapy protocol.