Cancer is a complex disease and is currently the leading cause of mortality
and morbidity across the globe. Dysregulated bioenergetics is one of the hallmarks of
cancer cells and is characterized by increased activity of several enzymes of metabolic
pathways. Consequently, cancer cells produce higher levels of reactive oxygen species
(ROS) which contribute to their enhanced proliferation and survival over normal cells.
Elevated levels of ROS cause oxidative stress, redox imbalance, DNA damage,
activation of oncogenes, chronic inflammation and eventually cancer. Additionally,
ROS mediated oxidative stress activates several oncogenic signaling cascades
including PI3K/Akt pathway, NF-κB pathway, cyclooxygenase pathway, JAK/STAT
pathway, angiogenesis and metastasis. To maintain redox balance and neutralize the
detrimental effects of ROS, normal cells exhibit an antioxidant defence system,
comprising of both enzymatic and non-enzymatic division. Activation of Nrf2
signaling pathway is the key regulatory pathway that helps in restoring the cellular
redox homeostasis. Extensive research in the past decades has witnessed the potential
health benefits of dietary antioxidants alone or in combination in the prevention of
several chronic diseases, including cancer. A number of antioxidants from dietary
backgrounds such as epigallocatechin gallate, resveratrol, curcumin, phloretin,
berberine and lycopene have shown appreciable potential as a chemopreventive agent
without causing significant toxicity. This chapter presents an extensive analysis of
existing knowledge on the protective effects of various dietary antioxidants against
cancer with a focus on oxidative stress, redox homeostasis and dysregulated cellular
signaling leading to cancer cell proliferation, survival and metastasis.
Keywords: Antioxidants, Cancer, Oxidative stress, Reactive oxygen species,
Redox homeostasis.
