Doxorubicin-induced gastrointestinal

Fig. 8. The preventive effects of chitosan on doxorubicin-induced gastrointestinal toxicity in sarcoma 180-beanng mice, a) small intestine weight b) sucrase activity in small intestinal mucosa.

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... 

Cytotoxic antibiotics depress the bone marrow, cause gastrointestinal upsets and stomatitis, alopecia, cardiomyopathy (daunorubicin and doxorubicin) and pulmonary fibrosis and skin rashes (bleomycin). Some of these effects are dose-dependent, for example, doxorubicin-induced cardiomyopathy. Others may be potentiated by concomitant use of radiotherapy. 

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