Medicinal Plants in the Prevention and Treatment of Colon Cancer
The standard treatment for cancer is generally based on using cytotoxic drugs, radiotherapy, chemotherapy, and surgery. However, the use of traditional treatments has received attention in recent years. The aim of the present work was to provide an overview of medicinal plants effective on colon cancer with special emphasis on bioactive components and underlying mechanisms of action. Various literature databases, including Web of Science, PubMed, and Scopus, were used and English language articles were considered. Based on literature search, 172 experimental studies and 71 clinical cases on 190 plants were included. The results indicate that grape, soybean, green tea, garlic, olive, and pomegranate are the most effective plants against colon cancer. In these studies, fruits, seeds, leaves, and plant roots were used for in vitro and in vivo models. Various anticolon cancer mechanisms of these medicinal plants include induction of superoxide dismutase, reduction of DNA oxidation, induction of apoptosis by inducing a cell cycle arrest in S phase, reducing the expression of PI3K, P-Akt protein, and MMP as well; reduction of antiapoptotic Bcl-2 and Bcl-xL proteins, and decrease of proliferating cell nuclear antigen (PCNA), cyclin A, cyclin D1, cyclin B1 and cyclin E. Plant compounds also increase both the expression of the cell cycle inhibitors p53, p21, and p27, and the BAD, Bax, caspase 3, caspase 7, caspase 8, and caspase 9 proteins levels. In fact, purification of herbal compounds and demonstration of their efficacy in appropriate in vivo models, as well as clinical studies, may lead to alternative and effective ways of controlling and treating colon cancer.
Overall, 1,150 articles were collected in the first step and unrelated articles were excluded later on according to title and abstract evaluation. Moreover, articles that did not have complete data along with congress and conference proceedings were excluded. Accordingly, a total of 1,012 articles were excluded in this step. Finally, 190 articles fulfilled the criteria and were included in this review. These papers were published within 2000-2017. A total of 190 plants were included in this study. Based on literature search, 172 experimental studies and 71 clinical cases were included.
Overall, results indicate that grape, soybean, green tea, garlic, olive, and pomegranate are the most effective plants against colon cancer. In these studies, fruits, seeds, leaves, and plant roots were used for in vitro and in vivo studies.
The findings of this review indicate that medicinal plants containing various phytochemicals, such as flavonoids, polyphenol compounds, such as caffeic acid, catechins, saponins, polysaccharides, triterpenoids, alkaloids, glycosides, and phenols, such as quercetin and luteolin, and kaempferol and luteolin glycosides, can inhibit tumor cell proliferation and also intduce apoptosis.