Momordin Ic is a natural
triterpenoid saponin enriched in various Chinese and Japanese natural medicines such as the fruit of Kochia scoparia (L.) Schrad. So far, there is little scientific evidence for
momordin Ic with regard to the anti-
tumor activities. The aim of this work was to elucidate the anti-
tumor effect of
momordin Ic and the signal transduction pathways involved. We found that
momordin Ic induced apoptosis in human
hepatocellular carcinoma HepG2 cells, which were supported by DNA fragmentation,
caspase-3 activation and PARP cleavage. Meanwhile,
momordin Ic triggered
reactive oxygen species (ROS) production together with collapse of mitochondrial membrane potential,
cytochrome c release, down-regulation of Bcl-2 and up-regulation of Bax expression. The activation of p38 and JNK, inactivation of Erk1/2 and Akt were also demonstrated. Although ROS production rather than NO was stimulated, the expression of iNOS and HO-1 were altered after
momordin Ic treatment for 4 h. Furthermore, the
cytochrome c release,
caspase-3 activation, Bax/Bcl-2 expression and PARP cleavage were promoted with
LY294002 and
U0126 intervention but were blocked by
SB203580,
SP600125, PI3K activator, NAC and 1,400 W pretreatment, demonstrating the mitochondrial disruption. Furthermore,
momordin Ic combination with NAC influenced MAPK, PI3K/Akt and HO-1, iNOS pathways, MAPK and PI3K/Akt pathways also regulated the expression of HO-1 and iNOS. These results indicated that
momordin Ic induced apoptosis through oxidative stress-regulated
mitochondrial dysfunction involving the MAPK and PI3K-mediated iNOS and HO-1 pathways. Thus,
momordin Ic might represent a potential source of anticancer candidate.