Mitochondria are important organelles referred to as cellular powerhouses for their unique properties of cellular energy production. With many pathologic conditions and aging, mitochondrial function declines, and there is a reduction in the production of adenosine triphosphate. The energy carrying molecule generated by cellular respiration and by pentose phosphate pathway, an alternative pathway of glucose metabolism. D-ribose is a naturally occurring monosaccharide found in the cells and particularly in the mitochondria is essential in energy production. Without sufficient energy, cells cannot maintain integrity and function. Supplemental D-ribose has been shown to improve cellular processes when there is mitochondrial dysfunction. When individuals take supplemental D-ribose, it can bypass part of the pentose pathway to produce D-ribose-5-phosphate for the production of energy.
D-ribose is an energy producing substrate of the ATP mole- cule and is often called the “molecular currency” because of its role in intracellular energy transfer. Adenosine triphosphate consists of phosphate, ribose, and adenosine groups that are connected through two high-energy phosphoanhydride bonds within the molecule. As a pentose sugar, D-ribose has five carbons in its ring structure; the chemical structure (Figure 3), and the molecu- lar weight is 150.13 g/mol (35). The ATP molecule is able to store and transport chemical energy within cells and is essential for synthesis of nucleus acids such as DNA and RNA. Ribose is a naturally occurring five-carbon sugar produced in the body through the PPP, a metabolic pathway parallel to glycolysis that generates nicotinamide adenine dinucleotide phosphate (NADPH), pentoses, and ribose 5-phosphate. The PPP is a slow process that requires an enzyme called glucose-6-phosphate dehydroge- nase (G-6-PDH) that is often in short supply within the cells. This enzyme can have limited expression in the myocardial cells with cardiac disease leading to significant delay in the production of ribose.