Natural Therapeutic Strategies for Modulating Oxidative Stress in Cancer

Abstract

The overproduction of free radicals provoked by oxidative stress is known to cause many diseases, including cancer, the latter being a significant health problem worldwide. Radical species like oxygen and nitrogen are reactive molecules that can damage biomolecules, such as DNA, RNA, lipids, nucleic acid, and proteins. Due to the presence of these reactive species, multiple signaling pathways might be activated. Cancer and other disorders caused by oxidative stress result from the disturbance in the balance between the production of reactive oxygen and nitrogen species (ROS, RNS) and their elimination. The antioxidant protection system is responsible for removing these reactive species from the body. Antioxidants are substances that protect cells against free radicals and reactive metabolites. They are produced endogenously by cells or obtained by food and supplement exogenously. Most antioxidants work by helping to eliminate pro-oxidants and scavenge the free radicals, resulting in reduced oxidative stress-mediated diseases. For centuries, diet, medicinal herbs, and spices are known as the major sources of antioxidants. Knowing that phenolic molecules are the well-known compounds responsible for the high contents of antioxidant activity, there are other natural compounds with similar or higher content. Recent studies have shown how natural products exhibiting antioxidant properties are revered as chemotherapeutic and radioprotective agents. These compounds are found in nature, such as in plants, nutraceuticals, bacteria, and fungi. Natural compounds used to treat cancer or being used in combination with traditional chemotherapies are reported in the present chapter.KeywordsCancerOxidative stressFree radicalsAntioxidantsChemotherapeutic plantNatural productsPolyphenolsMarine compoundsMicrobial antioxidative