**5.** *In vivo* **studies**

Reactive oxygen species (ROS) are produced by all aerobic cells and are important to the immune system, cell signaling, and many other normal body functions. They can elicit cellular damage, leading to degenerative diseases such as inflammation, cardiovascular disease, cancer, and aging if ROS are excessively produced [33–35]. As we mention previously, anthocyanins are potent antioxidants and their effectiveness has been tested *in vitro* and *in vivo*. They quench free radicals and terminate the chain reaction that is responsible for the oxidative damage. Because of the pH in the human body, their antioxidant activity at a neutral pH has a particular importance [36]. To assess the *in vivo* antioxidant activity of anthocyanins, an anthocyanin mixture was administered to mice/rats that were subjected to psychological stress [37, 38]. It was noticed that anthocyanins have similar antioxidant potency as vitamin E (α-tocopherol). Dietary anthocyanins have the potential to increase serum antioxidant capacity and thereby protect against LDL oxidation and prevent cardiovascular diseases as demonstrated in a human trial [39]. Deposits oxidized cholesterol into the artery wall can lead to atherosclerosis and eventually cardiovascular diseases [40]. Several studies have shown that anthocyanins have anti-obesity effect on high-fat diets and consequently may contribute to the prevention of type 2 diabetes. One of the studies demonstrates that black soybean anthocyanins were found to effectively reverse the weight gain of high-fat diet group rats [41]. Moreover, a number of different reports indicate that consumption of fruits and vegetables, especially rich in polyphenols, decrease the incidence of type-2 diabetes, a condition associated with insulin resistance [42, 43]. Nevertheless, evidence in the use of anthocyanins to

improve night vision was also revealed in other scientific articles [44, 45].

The uncontrolled growth of cells which can invade and spread to distant sites of the body is a global health problem, called cancer, with high mortality. Prevention and routine monitoring are critical to early and accurate diagnosis. Most therapeutic options do not offer cure but rather a deceleration of cancer progression. They not only aim at life extension and the improvement of patients' life quality but also often they have multiple side effects. In recent years, fruit and vegetables, including soft fruits such as berries, may represent a valid alternative than drugs with undesirable side and adverse effects, because of their chemopreventive or chemotherapeutic properties against certain diseases, such as cancer. Recent studies on the cancer preventative activities of the anthocyanins include results from *in vitro* cell culture and *in vivo* animal model tumor systems, as well as data from human epidemiological studies. Cancer cells differ from normal cells by a number of characteristics, thus being different in morphology and function. Anthocyanins can attack cancer cells due to these differences and cause a number of effects. A significant characteristic of cancer cells is their uncontrolled cell cycle, which leads to continuous division and proliferation. Pure anthocyanins and anthocyanin-rich extracts have demonstrated to inhibit cell proliferation by the ability of anthocyanins to block various stages of the cell cycle [46, 47]. Moreover, they can selectively inhibit the proliferation of cancer cells, but have little influence on the proliferation of normal cells [48, 49]. Anthocyanins have demonstrated to induce the apoptosis of cancer cells through the internal mitochondrial pathway and the external death receptor pathway. Usually, apoptosis,

**4. Anticancer properties of anthocyanins**

78 Phytochemicals - Source of Antioxidants and Role in Disease Prevention

In carcinogen-treated animals and also animals with a hereditary predisposition to cancer, anthocyanins have been shown to inhibit the development of cancer. Moreover, they have been proven effective in: esophageal cancer, colon cancer, skin cancer, and lung cancer. After treatment, administration in different forms, such as anthocyanin-rich tart cherry extract, black raspberry powder, lyophilized black raspberries or ethanol: H<sup>2</sup> O extract from berries, certain effects, were observed. All diets were equally effective in preventing the development of tumors, reducing tumor numbers by 42–47%, suggesting that anthocyanins in the fruits are important for their chemopreventive activity. A small summary of several types of cancer will be discussed further.
