In vitro evaluation of the apoptotic and antimitotic (cytostatic) effects of Arum palaestinum and Peganum harmala

The incidence of cancer is increasing in the developed countries and even more so in developing countries parallel to the increase in life expectancy. Cancer is a result of an accelerated and uncontrolled cellular proliferation and low rate of apoptosis (programmed cell death) leading to an increasing mass of cells termed as tumor. Mitochondria play a crucial role in the induction of this apoptosis. It is involved in the release of apoptogenic intermediates such as cytochrome c from the intermembrane space. These apoptogenic intermediates appear to play a central role in initiation of a cascade that leads to programmed cell death . Advanced tumors are treated usually by chemotherapy and although these drugs are effective, they are associated with severe adverse events and drug resistance. Several studies have revealed that natural products exhibit an extensive spectrum of biological activities such as stimulation of the immune system, antibacterial, antiviral, anti-hepatotoxic, anti-ulcer, anti-inflammatory, antioxidant, anti-mutagenic, anti-cancer effects, as well as apoptosis induction. The traditional Arab-Islamic herbal-based medicines might be promising candidates for new cancer therapeutics, especially natural herbal products with low toxicity and minimal side effects. Two medicinal plants were selected to investigate their anti-cancer effect: (Arum palaestinum and Peganum harmala (AP and PH). Three cancer cell lines: Colon, Prostate and Lung (HCT-116, PC3, A549) and one normal (control) cell line (skeletal muscle, L6) were selected to test the efficacy of AP and PH in apoptosis induction. The cells were treated with an increasing concentration of 50%water/50% ethanol plant extracts (0 , 8, 16, 32, 62, 125, 250, 500 and 1000 µg/ml) for 24h. Then we used MTT assay to test cytotoxicity of the extracts and Annexin V-Cy3 to test apoptosis. Results shows that Peganum harmala has non-toxic effect on all treated cell lines at concentrations less than 250 µg/ml. However, it had induced apoptosis in prostate cancer cell line (PC3), muscle cell line (L6), and lung cancer cell line (A549). Surprisingly, Arum palaestinum had no cytotoxic or apoptotic effect in all selected cell lines, even at 1000 µg/ml.