Synsepalum dulcificum extracts exhibit cytotoxic activity on human colorectal cancer cells and upregulate c-fos and c-jun early apoptotic gene expression

ABSTRACT

Objective:To explore cytotoxicity of Synsepalum dulcificum (S.dulcificum) Daniell (Sapotaceae) on human colon cancer (HCT-116 and HT-29),human monocytic leukemia (THP-1) and normal (HDFn) cell lines,and its effect on the expression of early apoptotic genes,c-fos and c-jun.Methods:Leaf,stem and berry of S.dulcificum were separately extracted by using 2 solvents,10％ ethanol (EtOH) and 80％ methanol (MeOH).PrestoBlue(R)cell viability assay and qRT-PCR assay were conducted to examine the above objectives respectively.Results:Stem MeOH,stem EtOH,and berry EtOH extracts of S.dulcificum were cytotoxic to HCT-116 and HT-29 human colon cancer cells.For HCT-116,IC50 values of these 3 extracts were not significantly different (P＞0.05) from that of the positive control bleomycin (IC5o of 33.57 μg/mL),while for HT-29,IC5o values of these 3 extracts were significantly lower (P＜0.05) than that of bleomycin (IC50 of 25.24 μg/mL).None of the extracts were cytotoxic to the THP-1 monocytic leukemia cells and HDFn normal human dermal fibroblasts.For both HCT-116 and HT-29,these extracts significantly up-regulated (P＜0.05) the expression of c-fos and c-jun compared to the untreated negative control.Conclusions:The results of this study suggest that cytotoxicity of stem MeOH,stem EtOH,and berry EtOH extracts of S.dulcificum on HCT-116 and HT-29 colon cancer cells is due to the induced apoptosis which is caused by the up-regulation of the expression of early apoptotic genes,c-fos and c-jun.