Antioxidants antineoplastic agents

Ellagic acid is an astringent, hemostatic, antioxidant, antimutagenic, and possibly an antineoplastic agent from strawberries, raspberries, grapes, walnuts, and pecans. Its human dietary role in cancer prevention is uncertain and in planta function is unknown. 

Chemotherapy is a common method of treatment for many types of cancer. The side effects of chemotherapy come about in part because cancer cells are not the only dividing cells in the body. Chemotherapeutic agents cause increased production of free radicals that can be harmful for normal cells, and these free radicals can be bound by antioxidant vitamins and supplements, including lycopene. A large number of studies have reported the beneficial effects of a variety of antioxidants in antineoplastic agents-induced nephrotoxicity, hepatotoxicity, ototoxicity, and peripheral neuropathy [218, 219]. Chemoprotective activities of lycopene [219, 220], and other dietary components that scavenge free radicals induced by exposure to antineoplastic agents [218, 220] have been well documented (Table 129.2). 

Oxidative stress reduces the rate of cell proliferation, and that occurring during chemotherapy may interfere with the cytotoxic effects of antineoplastic drugs, which depend on rapid proliferation of cancer cells for optimal activity. Antioxidants detoxify ROS and may enhance the anticancer effects of chemotherapy. For some supplements, activities beyond their antioxidant properties, such as inhibition of topoisomerase II or protein tyrosine kinases, may also contribute. ROS cause or contribute to certain side effects that are common to many anticancer drugs, such as gastrointestinal toxicity and muagenesis. ROS also contribute to side effects that occur only with individual agents, such as doxorubicin-induced cardiotoxicity, cisplatin-induced nephrotoxicity, and bleomycin-induced pulmonary fibrosis. Antioxidants can reduce or prevent many of these side effects, and for some supplements the protective effect results from activities other than their antioxidant properties. Certain side effects, however, such as alopecia and myelosuppression, are not prevented... 

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