الفهرس 
Colorectal cancer and apoptosisOnly 14 pages are availabe for public view
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Abstract
Etiological studies showed that more than 85% colorectal cancer cases are associated with environmental factors, particularly the dietary factor. Among dietary constituents implicating in colorectal carcinogenesis, consumption of vegetables and fruits has a beneficial effect. Great advancements have been made in the treatment and control of cancer progression. Several undesired side effects occur during chemotherapy. Natural therapies, such as the use of plantderived products in cancer treatment, may reduce adverse side effects. Currently, a few plant products are being used to treat cancer. However, a myriad of many plant products exist that have shown very promising anti-cancer properties in vitro, but have to be evaluated in humans. Phytochemicals play nutritional roles in diets and possess medicinal properties. These bioactive agents manifest their usefulness over mono-therapy by working in consortium and exert synergistic, polyvalent and pharmacological effects in humans as nutraceutical that serve as functional foods; as crude drugs for health benefits including prevention and treatments of chronic metabolic diseases such as coronary heart disease, diabetes and obesity. The present study aimed to screen the phytochemical constituents of some natural products extract including red cabbage leaves, broccoli florets, peanuts seed coats and sweet red pepper. The study was extended to address the anti-proliferative effects of these extracts against colorectal cancer cell lines. Furthermore, the molecular mechanism of the antitumor effect was investigated by gene expression analysis of apoptotic (caspase 3 and Bax) and antiapoptotic (Bcl-2) genes by using real time polymerase chain reaction (RT-PCR). Results were statistically analyzed and can be summarized as the following • The results showed that the highest levels of phytochemical constituents were observed in red cabbage leaves and broccoli floaters plants ethanolic extract. Total phenolic levels in the aqueous ethanolic extracts of red cabbage leaves, broccoli florets, peanut coats and sweet red pepper were 1.532, 1.298, 1.086 and 1.191 mg/ml gallic acid equivalents (GAE) per 1 ml of extract, respectively. Determination of flavonoids levels were 0.169, 0.127, 0.136 and 0.158 mg/ml quercetin equivalent/ml extract, respectively. Furthermore, the present study was extended to estimate the total antioxidant capacity (TAC) in the different extracts under study. The data showed that red cabbage has the highest capacity of the total antioxidant power and the peanut coats showed the lowest values. The percentage of DPPH scavenging for free radicals was 61% in red cabbage leaves, 51% in broccoli floaters, 55% in peanuts coats and in sweet red pepper was 58%. The ethanol extracts from each showed a concentrationdependent DPPH scavenging activity with IC50 values of 0.081, 0.109, 0.197 and 0.098 mg/ml in red cabbage leaves, broccoli florets, peanut coats and red sweet pepper, respectively. • The results reported that red cabbage leaves, broccoli florets , the peanuts seed coats and sweet red pepper extracts exhibited selective cytotoxicity in the colon cancer cell line with IC50 value 30.04, 6.64, 30.5 and 25.1 μg/ml, respectively. • The levels of malondialdehyde (MDA) was significant decrease in the colorectal cell lysate at the different extract treatments including red cabbage, broccoli florets, peanut seed coats and sweet red pepper when compared with the control cells. Reduced glutathione (GSH) levels in colorectal cell lysate at different treatment conditions were significantly increased in cells treated with red cabbage leaves, broccoli florets and sweet red pepper extracts. Peanut seed coats extract showed non-significant increase in GSH levels when compared with the colorectal control cells. Catalase activity was significantly increased in cells treated with red cabbage leaves, broccoli florets and sweet red pepper extracts reached as compared to their control. Peanut seed coats extract showed non-significant increase in catalase activity when compared with the colorectal control cells. Superoxide dismutase (SOD) activity was increased significantly after red cabbage leaves and broccoli florets extracts exposure. • Data obtained from qPCR revealed a significant upregulation in the apoptotic gene expression level (Bax) in CaCo2 cells following the treatment of the four extracts under study with the highest significant upregulation in the extract from broccoli florets and the lowest upregulation was observed in the extract from peanut seed coats as compared to control human colon cancer cells. No significant difference in the expression level of Bax gene was shown between red cabbage leaves extract and sweet red pepper extract following treatment. Furthermore, there was a significant upregulation in the expression level of (caspase 3) in CaCO2 cells following administration of the four extracts with the highest significant upregulation in the extract of broccoli florets and the lowest in the peanut seed coats extract. There was a significant downregulation in the expression level of the anti-apoptotic gene (Bcl-2), in CaCO2 cells following administration of the four extracts under study with the lowest expression in the extract of broccoli florets and the highest expression in the ethanolic extract of red cabbage leaves as compared to CaCO2 cells alone as a control. No significant difference in the expression level of Bcl-2 gene was shown between the peanut seed coat extract and the sweet red pepper following treatment.