Inositol

Absorption

Inositol is absorbed from the small intestine. In patients with inositol deficiency, the maximal plasma concentration after oral administration of inositol is registered to be of 4 hours. Inositol is taken up by the tissues via sodium-dependent inositol co-transporter which also mediates glucose uptake. Oral ingestion of inositol is registered to generate a maximal plasma concentration of 36-45 mcg.

Toxicity

Consumption of high doses of inositol is reported to only cause some gastrointestinal effects.

Description

Inositol (hexahydroxycyclohexane) is a widely distributed natural constituent of plant and animal tissues. The animal tissues richest in inositol are brain, heart, stomach, kidney, spleen, and liver, where it occurs free or as a component of phospholipids. Among plants, cereals are rich sources of inositol, particularly in the form of polyphosphoric acid esters, called phytic acids. Although there are several possible optically active and inactive isomers, considerations of inositol as a food additive refer specifically to optically inactive cis-1,2,3,5-trans-4,6-cyclohexanehexol, which is preferably designated myo-inositol. Pure inositol is a stable, white, sweet, crystalline compound. The Food Chemicals Codex specifies that it assay not less than 97.0 percent, melt between 224 and 227°, and contain not more than 3 ppm arsenic, 10 ppm lead, 20 ppm heavy metals (as Pb), 60 ppm sulfate, and 50 ppm chloride. Inositol was thought for a time to be a vitamin because experimental animals on a synthetic diet developed clinical signs that were corrected by inositol supplementation. However, no cofactor or catalytic function for inositol has been found; it can be synthesized and occurs in relatively high concentration in animal tissues. These factors argue against its classification as a vitamin. A dietary requirement in man has not been established.

The Uses of Inositol

Myo-Inositol is a growth factor for animals and microorganisms. It is the most abundant form of polyols that serves as a structural element of secondary messengers in eukaryotic cells. It is used as an adulterant in many illegal drugs like cocaine and methamphetamine. Further, it is used as a stand-in for cocaine on television and film.

Background

Inositol is a collection of nine different stereoisomers but the name is usually used to describe only the most common type of inositol, myo-inositol. Myo-inositol is the cis-1,2,3,5-trans-4,6-cyclohexanehexol and it is prepared from an aqueous extract of corn kernels by precipitation and hydrolysis of crude phytate. These molecules have structural similarities to glucose and are involved in cellular signaling. It is considered a pseudovitamin as it is a molecule that does not qualify to be an essential vitamin because even though its presence is vital in the body, a deficiency in this molecule does not translate into disease conditions. Inositol can be found as an ingredient of OTC products by Health Canada but all current product whose main ingredient is inositol are discontinued. By the FDA, inositol is considered in the list of specific substances affirmed as generally recognized as safe (GRAS).

Indications

Inositol may be used in food without any limitation. As a drug, inositol is used as a nutrient supplement in special dietary foods and infant formula. As it presents a relevant role in ensuring oocyte fertility, inositol has been studied for its use in the management of polycystic ovaries. Inositol is also being researched for the treatment of diabetes, prevention of metabolic syndrome, aid agent for weight loss, treatment of depression, psychiatric disorder and anxiety disorder and for prevention of cancer.

What are the applications of Application

myo-Inositol is a growth-factor and structural element of secondary messengers in eukaryotic cells

Pharmacokinetics

Inositol can stimulate glucose uptake in skeletal muscle cells which allows the decrease in blood sugar levels. This effect is later seen as a reduction in urine glucose concentration and indicates a decrease in high blood sugar levels.
In PCOS, the administration of inositol has produced the remission of symptoms as well as a reduction in male hormone secretion, a regulation of the cholesterol level, and a more efficient fat breakdown which allow to a significant reduction on body mass and appetite.
In the cases of infertility, inositol has been proven to increase sperm count and motility, as well as increase the overall quality of oocytes and embryos.
In the brain, inositol has been shown to produce an increase in serotonin receptor sensitivity. This activity produces an increase in GABA release. Some of the effects observed in the brain produced a relief in symptoms of anxiety and obsessive-compulsive disorders. In high doses, it has been shown to even reduce panic attacks.
In cancer research, inositol has gained interest as it can act as an antioxidant, anti-inflammatory and it seems to enhance immune properties.

Metabolism

It is thought that inositol is metabolized to phosphoinositol and then converted to phosphatylinositol-4,5-biphosphate which is a precursor of the second-messenger molecules. Inositol can be transformed to D-chiro-inositol via the actions of an epimerase. The normal modifications to inositol structure seem to be between all the different isomers.