Nasser Elhawary, Ezzeldin2019-10-152019-10-152018Copyright © 2019 MSA University. All Rights Reserved.https://t.ly/23q2bNature 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.enOctober University for Modern Sciences and ArtsUniversity for Modern Sciences and ArtsMSA universityجامعة أكتوبر للعلوم الحديثة والآدابCytotoxicBiomolecularOther