For medicinal chemistry, the in-depth study of organic substances that are fundamentally important for the body is of great importance. Among a large number of such molecules, glucose deserves special attention because it comes with food and is consumed to form energy in the form of ATP molecules. In terms of its molecular structure, glucose is a typical monosaccharide of the hexose category. The chemical properties of glucose are justified by the presence of two types of active groups at once: one carbonyl group and five hydroxyl groups. Thus, glucose is a polyhydroxy aldehyde and can both be reduced to six-atomic alcohol (sorbitol) and oxidized to gluconic acid. Notably, glucose can be oxidized through other metabolic pathways in the body, forming either Penta-carbon sugars or pyruvic acid, which are involved in the energy cycle.
As the simplest hexose, glucose has isomers. Among them are galactose and fructose, with galactose being the optical isomer of glucose, while fructose is the structural isomer. However, having a standard formula does not mean that the conditions are the same. On the contrary, while glucose and fructose can be found in natural sugars, especially in fruits and berries, galactose is part of lactose or milk sugar. Consequently, the ingestion of galactose is associated with the consumption of dairy products, including breast milk. At the same time, it is noteworthy that when dissolved in water, glucose changes its shape from linear to circular, becoming a six-membered ring. This state contains more than 99% of all glucose in the body. Moreover, even in the ring form, glucose can be represented by alpha and beta variants, which differ in the location of the hydroxyl group at the first carbon.
There are several tests for determining glucose. A standard biochemical blood test quantifies blood glucose levels. This procedure is routine in clinical practice and helps predict the development of diabetes. With glucose meters, patients can determine blood glucose levels at the puncture point: this allows sugar levels to be monitored and measures are taken to regulate them. Finally, a scientific biochemical glucose test is called the Benedict test. It allows the qualitative detection of reducing sugars in solution by staining a mixture of glucose and Benedict’s reagent in yellow-red colors depending on the concentration.