Reactive oxygen species (ROS) played an important role in cancer. Although low levels of ROS can be beneficial in normal physiological functions, chronic exposure to ROS is associated with increased risk of cancers. Increased ROS levels can also induce apoptosis and cell death in various types of cancer. Taken together, the role of ROS in cancer prevention, formation and therapy is extremely complex and very challenging to study. Although the antioxidant activity of phytochemicals is well recognized and generally used to prevent cancer, they can have pro-oxidant and ROS generating activities under certain conditions, especially at high doses or in the presence of metal ions. The basal redox levels of cancer cells are also different from those of normal cells. Therefore, higher levels of free form of metal ions and higher levels of endogenous ROS production in cancer cells sensitizes them to phytochemicals mediated pro-oxidant cytotoxicity. In conclusion, people tend to intake of antioxidant phytochemicals for the detrimental effects of ROS. However, excessive intake of phytochemicals could have cancer development or therapeutic potential by generating ROS. In this section, the role of phytochemicals in the prevention, development and removal of cancer has been discussed.
Part of the book: Reactive Oxygen Species (ROS) in Living Cells