The main physiological actions of the biologically most active metabolite of vitamin C (ascorbate or ascorbic acid), is a nutrient essential to the biosynthesis of collagen and L-carnitine and the conversion of dopamine to norepinephrine. Other emergent areas of vitamin C action are in the control of immune functions, cellular growth and differentiation. Most animals are able to synthesize large quantities of ascorbate, but humans lost this ability due to mutations of the gulonolactone oxidase gene. As a pro-oxidant, ascorbate generates hydrogen peroxide–dependent cytotoxity in cancer cells without adversely affecting normal cells. It is well known that an acute lack of ascorbate leads to scurvy and causes death and vitamin C is an attractive marker of fruit and vegetable intake because these foods are the primary sources of dietary vitamin C. Evidence of ascorbate-sensing and -response mechanisms was found that could be hormonally mediated in animals. In vitro studies have already shown that pharmacologic ascorbate is effective in a large panel of tumor cell lines and that increasing tumor cells’ generation of hydrogen peroxide (H2O2) might be used to induce ascorbate-specific cytotoxicity, which has been found to mediate the mitochondrial release of cytochrome C, leads to H2O2-mediated activation of the caspase cascade and apoptotic process, and thence to a significant decrease in the growth rate of some solid tumors. Moreover, in vivo, high-dose ascorbate has been investigated to improve the health-related quality of life of terminal cancer and infectious diseases patients. In this research topic, we present different perspectives on the action of vitamin C and its transporters, ii) the physiological role of vitamin C in health, iii) biochemical effects and molecular mechanisms of vitamin C, iv) the involvement of vitamin C in infectious diseases, and v) the use of high dose of vitamin C as an anticancer agent.
The main physiological actions of the biologically most active metabolite of vitamin C (ascorbate or ascorbic acid), is a nutrient essential to the biosynthesis of collagen and L-carnitine and the conversion of dopamine to norepinephrine. Other emergent areas of vitamin C action are in the control of immune functions, cellular growth and differentiation. Most animals are able to synthesize large quantities of ascorbate, but humans lost this ability due to mutations of the gulonolactone oxidase gene. As a pro-oxidant, ascorbate generates hydrogen peroxide–dependent cytotoxity in cancer cells without adversely affecting normal cells. It is well known that an acute lack of ascorbate leads to scurvy and causes death and vitamin C is an attractive marker of fruit and vegetable intake because these foods are the primary sources of dietary vitamin C. Evidence of ascorbate-sensing and -response mechanisms was found that could be hormonally mediated in animals. In vitro studies have already shown that pharmacologic ascorbate is effective in a large panel of tumor cell lines and that increasing tumor cells’ generation of hydrogen peroxide (H2O2) might be used to induce ascorbate-specific cytotoxicity, which has been found to mediate the mitochondrial release of cytochrome C, leads to H2O2-mediated activation of the caspase cascade and apoptotic process, and thence to a significant decrease in the growth rate of some solid tumors. Moreover, in vivo, high-dose ascorbate has been investigated to improve the health-related quality of life of terminal cancer and infectious diseases patients. In this research topic, we present different perspectives on the action of vitamin C and its transporters, ii) the physiological role of vitamin C in health, iii) biochemical effects and molecular mechanisms of vitamin C, iv) the involvement of vitamin C in infectious diseases, and v) the use of high dose of vitamin C as an anticancer agent.
