Molecular Mechanisms Underlying the Anti-Cancer Effects of Tangeretin, a Phytochemical from Citrus Extracts

Cancer is one of the diseases with high incidence and mortality rates. As a result, many studies have led to the development of therapeutic agents such as immune checkpoint inhibitors. However, the research on cancer treatment is still essential because of problems including drug resistance, genetic variation among patients, and drug toxicity. To address these problems, several candidate chemicals, including phytochemicals, have been studied for cancer treatment. Phytochemicals exhibit a variety of biochemical and physiological functions in the body and have been studied as having lower toxicity than synthetic chemicals. These properties have led to research into their potential as anti-cancer agents as well as their therapeutic applications for a variety of other diseases. The structural diversity of phytochemicals leads to considerable variations in their mechanisms of action. Therefore, it is important to understand the mechanism of action of each phytochemical when studying phytochemicals. Tangeretin (TAN) is mainly extracted from citrus fruits and is characterized by the presence of a methyl group. The presence of a methyl group in TAN is thought to enhance its intracellular uptake and confer greater resistance to degradation compared with other phytochemicals. Previous studies on the use of TAN in cancer treatment have mainly focused on its ability to induce oxidative stress as the primary anti-cancer mechanism. In addition, some studies suggest that TAN also exerts various other anti-cancer effects, such as upregulating tumor suppressor proteins, inducing apoptosis, and reducing the proportion of cancer stem cells (CSCs). This review highlights the anti-cancer effects of TAN in different cancers and aims to provide data to support future research.