Sorbitol is a polyhydric alcohol with about half the sweetness of sucrose. Sorbitol occurs naturally and is also produced synthetically from glucose. It was formerly used as a diuretic and may still be used as a laxative and in irrigating solutions for some surgical procedures. It is also used in many manufacturing processes, as a pharmaceutical aid, and in several research applications. L-Sorbitol is a sugar alcohol also known as glucitol. Used as a non-stimulant laxative via an oral suspension or enema. Sorbitol exerts its laxative effect by drawing water into the large intestine, thereby stimulating bowel movements. Sorbitol plays a vital step in the 'polyol pathway'. The sudden injection of extra sorbitol can ruin the equilibrium of enzymes that regulate the conversion of glucose to fructose in a process associated with the onset of diabetes and its complications. Further, the polyol pathway is involved with a complex network of metabolic activities; disruption leads to a cascade of problems (citations here, here and here) such as mitochondrial failure, cell apoptosis (cell death), and DNA fragmentation. In general, sorbitol induces cell hyperosmotic stress resulting in phosphorylation (uptake of phosphorus into cell) — an important on/off switch regulating enzymes and signaling networks. Bradyrhizobium japonicum sorbitol dehydrogenase is NADH-dependent and is active at elevated temperatures. The best substrate is D-glucitol, although L-glucitol (L-glucitol) is also accepted, giving it particular potential in industrial applications.

Lactic acid, D- is a natural optical isomer of lactic acid. It is a poorly utilized isomer – 30 to 40% of the dose ingested is excreted in the urine. Lactic acid, D- is known to be harmful to human metabolism and it can result in acidosis and decalcification. D-lactic acidosis, also referred as D-lactate encephalopathy, has been reported in patients with short bowl syndrome. Lactic acid, D- is an interesting precursor for manufacturing heat-resistant polylactic acid (PLA) bioplastics which can be widely used, for example as packaging material, coatings, for textiles or in the automotive industry.