**4. Effects of anthocyanins in the prevention and treatment of diseases**

#### **4.1 Antitumor effects of anthocyanins**

Environmental pollution, excessive intake of junk food, irregular life, and other bad habits can lead the human body to induce certain carcinogens. The cancerogens

### *Anthocyanins: Novel Antioxidants in Diseases Prevention and Human Health DOI: http://dx.doi.org/10.5772/intechopen.89746*

are metabolized and activated to produce free radicals to attack DNA to cause cancer; whereas, the carcinogenic ability of cancerogens is positively correlated to their ability of free radicals produced. At present, it has been confirmed that the increase of oxygen free radical and the change of antioxidant enzyme activity can result in the occurrence of tumors. Moreover, tumor patients usually show the imbalanced oxidoreduction state in the body and the interaction between tumors and antioxidant systems. Studies have shown that anthocyanins can exert antitumor activity by an antioxidant. The in vitro and in vivo experiments have exhibited that anthocyanins inhibit proliferation of tumor cell and development of tumor. The antitumor mechanism of anthocyanins may be related to their effective antioxidant capacity and cyclooxygenase inhibited. It is reported that *Nelumbo nucifera* Gaertn proanthocyanidins inhibited the colony formation and growth of melanoma B16 cells by a dose-dependent manner [15]. The in vitro studies by He et al. found that proanthocyanidins inhibited the proliferation of human colon cancer cell line SW620 in a concentration-dependent manner and activated the mitochondrial apoptosis pathway to promote the apoptosis of SW620 cells [16]. Many studies reported that proanthocyanidins can inhibit the proliferation and promote the apoptosis of SKOV3 cells by decreasing the expression of survival protein survivin and fight against the *Croton tiglium*-induced mouse skin papilloma formation and lessen tumor number and occurrence. Its mechanism of action is that proanthocyanidins can lower the content of NO of the skin in mice, and NO is regarded to be involved in the formation of dermal papilloma in mice [17, 18]. Studies by Zhang found that proanthocyanidins have a strong radiation sensitization action in SPC-A-1 cells of lung cancer [19]. In addition, proanthocyanidins showed good anticancer activity for liver cancer, prostate cancer, skin cancer, and other cancers. With the deepening of the research, proanthocyanidins will play a greater role in the prevention and treatment of cancer [20].
