An anticancer effect of a new saponin component from Gymnocladus chinensis Baillon through inactivation of nuclear factor-kappaB.

Gymnocladus chinensis Baillon is widely distributed in China, and its fruits have been used in the treatment of rheumatism, furunculosis, soreness and swelling in traditional Chinese medicine for a long time. Few biological components were, however, isolated. In this study, a new triterpenoid saponin (GC-1) was extracted from the fruit of Gymnocladus chinensis Baillon and its biological actions were investigated. The results showed that GC-1 inhibited growth of a panel of human cancer cell lines in vitro by 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyl tetrazolium bromide and sulforhodamine B assays. Furthermore, GC-1 was demonstrated to induce apoptosis in HL-60 cells in a dose-dependent manner. By using a reporter gene assay, nuclear factor-kappaB activity induced by tumor necrosis factor-alpha was decreased gradually by addition of increasing concentration of GC-1 (1-40 micromol/l). In parallel, the blockage of nuclear factor-kappaB translocation from cytoplasm to nucleus was determined by Western blotting. This is the first study investigating the link of antiproliferative action of the compound with the inhibition of nuclear factor-kappaB activation. The mechanism of the actions of GC-1 might be due to the interruption of nuclear factor-kappaB translocation in the signaling pathway, which contributes to the chemotherapy potential.