Abstract:
Nature is a main source for discovering new drugs and it has played a major role in the
development of new chemotherapeutic candidates. Natural products offer a wide variety of
chemical structures with different biological activities that can be used for the development of
novel drugs. Around 60% of the current anticancer drugs were isolated from natural products
(Newman and Cragg, 2006). In this study, I attempted to exploit five plant extracts, Euphorbia
hierosolymitana (herb), Sapium sebifera (branch), Cordyline fruticosa (leaf and branch),
Dracerna marginata (bark) and Dracaena marginata (leaf and branch), and show their
cytotoxic activities on different human cancer cell line including breast carcinoma (MCF-7),
hepatocellular carcinoma (HepG-2), colon carcinoma (HCT116) and prostate cancer (PC3),
and normal skin cell line (BJ-1). Methanol extracts of these plants underwent MTT cytotoxic
assay and found that E. hierosolymitana selectively inhibited HCT116 cell proliferation with
IC50 of 4.22 μg/ml, both Dracaena marginata extracts (bark and leaf & branches) showed
moderate cytotoxicity on MCF-7 with IC50 of 22.4 and 48.2 μg/ml, respectively. The remaining
two extracts showed minimal to insignificant percentage inhibition on all cell lines. E.
hierosolymitana extract was selected for further studying, where the effect of the extract on the
HCT116 cells showed a downregulation of her2 and Bcl-2 gene and an overexpression of the
Bax gene. Flow cytometry analysis were also performed to understand the effect of E.
hierosolymitana on the apoptosis induction and the cell cycle. And the results showed induction
of early and late apoptosis by 5.81 and 10.01%, respectively. Our results infer that E.
hierosolymitana have a promising chance in fighting colorectal cancer due to its high cytotoxic
effects on HCT116 cancer cells while having minimal effects on the BJ-1 normal cells lines.
