inositol

myo-Inositol[1]
IUPAC name	cis-1,2,3,5-trans-4,6 -Cyclohexanehexol
Other names	(1r,2R,3S,4s,5R,6S)-cyclohexane-1,2,3,4,5,6-hexol, Cyclohexanehexol, Cyclohexitol, Dambose, Inosital, Inosite, iso-Inositol, Inositene, Inositina, i-Inositol, Inositol, MI, Meat sugar, Mesoinosit, Mesoinosite, meso-Inositol, Mesol, Mesovit, Myoinosite, Mouse antialopecia factor, Nucite, Phaseomannite, Phaseomannitol, Rat antispectacled eye factor, and Scyllite (for the structural isomer scyllo-Inositol)
Identifiers
CAS number	87-89-8 Y
SMILES	O[C@H]1[C@H](O)[C@@H](O)[C@H](O)[C@H](O)[C@@H]1O
Properties
Molecular formula	C6H12O6
Molar mass	180.16 g mol−1
Density	1.752 g/cm³
Melting point	225-227 °C
Y (what is this?)  (verify) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Inositol or cyclohexane-1,2,3,4,5,6-hexol is a chemical compound with formula C₆H₁₂O₆ or (-CHOH-)₆, a sixfold alcohol (polyol) of cyclohexane. It exists in nine possible stereoisomers, of which the most prominent form, widely occurring in nature, is cis-1,2,3,5-trans-4,6-cyclohexanehexol, or myo-inositol. Other naturally occurring isomers (though in minimal quantities) are scyllo-, muco-, D-chiro-, and neo-inositol. The other possible isomers are L-chiro-, allo-, epi-, and cis-inositol.

Myo-inositol plays an important role as the structural basis for a number of secondary messengers in eukaryotic cells, including inositol phosphates, phosphatidylinositol (PI) and phosphatidylinositol phosphate (PIP) lipids. It is found in many foods, in particular, in cereals with high bran content, nuts, beans, and fruit, especially cantaloupe melons and oranges. Inositol is not considered a vitamin itself because it can be synthesised by the body.

Myo-Inositol was classified as a member of the vitamin B complex (often referred to as vitamin B8), but was found to be synthesized by the human body (thus, declassifying it as a vitamin^{[citation needed]}). It should be noted, however, that substances such as niacin and choline can also be synthesized in the body, but are not made in amounts considered adequate for good health, and are classified as essential nutrients.

Structure

In its most stable geometry, the inositol ring is in the chair conformation. The natural myo isomer has a structure in which the 1^st, 3^rd, 4^th, 5^th, and 6^th hydroxyls are equatorial, whereas the 2^nd hydroxyl group is axial.^[2]

Synthesis

Myo-Inositol is synthesized from glucose-6-phosphate (G-6-P) in two steps. First, G-6-P is isomerised by ISYNA1 to myo-inositol 1-phosphate, which is then dephosphorylated by IMPase 1 to give free myo-inositol.

myo-	scyllo-	muco-	chiro-
neo-	allo-	epi-	cis-

Function

Inositol and a number of its mono and polyphosphates function as the basis for a number of signaling and secondary messenger molecules. They are involved in a number of biological processes, including:

• Insulin signal transduction^[3]
• Cytoskeleton assembly
• Nerve guidance (Epsin)
• Intracellular calcium (Ca²⁺) concentration control ^[4]
• Cell membrane potential maintenance^{[citation needed]}
• Serotonin activity modulation
• Breakdown of fats and reducing blood cholesterol^{[citation needed]}
• Gene expression^[5][6]

Phytic acid in plants

Phytic acid, which is inositol hexakisphosphate (IP6), also known as phytate when in salt form, is the principal storage form of phosphorus in many plant tissues, especially bran and seeds.^[7]

Inositol penta- (IP5), tetra- (IP4), and triphosphate (IP3) are also called "phytates."

Clinical implications

Psychiatric conditions

Patients suffering from clinical depression generally have decreased levels of inositol in their cerebrospinal fluid.^[8]

Some preliminary results of studies on high dose inositol supplements show promising results for people suffering from problems such as bulimia, panic disorder, obsessive-compulsive disorder, agoraphobia, and unipolar and bipolar depression.^[8]

Myo-inositol has been found, in a single double-blind study on 13 patients, to significantly reduce the symptoms of obsessive-compulsive disorder (OCD) with effectiveness equal to SSRIs and virtually without side-effects.^[9] In a double-blind, controlled trial, myo-inositol was superior to fluvoxamine for decreasing the number of panic attacks and had fewer side effects.^[10] A double-blind, placebo-controlled study of depressed patients showed that a high dose of inositol (12 grams daily) resulted in significant improvement of symptoms, with no changes noted in liver, kidney, or hematological function.^[8]

Research suggests that lithium functions primarily by decreasing myo-inositol concentrations in bipolar patients.^[11][12] Other studies suggest that lithium treatment may further inhibit the enzyme inositol monophosphatase leading to higher intracellular levels of inositol triphosphate,^[13] an effect which was enhanced further by administration of an inositol triphosphate reuptake inhibitor.

Other conditions

D-chiro-inositol (DCI) has been found in two double-blind studies to be an effective treatment for many of the clinical hallmarks of polycystic ovary syndrome (PCOS), including insulin resistance, hyperandrogenism, and oligo-amenorrhea.^[14][15] The impetuses for these studies were the observed defects in DCI metabolism in PCOS and the implication of DCI in insulin signal transduction.^[3][16]

Animal studies suggest inositol reduces the severity of the osmotic demyelination syndrome if given prior to rapid correction of chronic hyponatraemia.^[17] Further study is required prior to its application in humans for this indication.

Studies from in vitro experiments, animal studies, and limited clinical experiences, claim that inositol may be used effectively against some types of cancer, in particular, when used in combination with phytic acid.^[18]

Use in hair care

According to some reports, Inositol strengthens the cells of the hair helping it to retain moisture. It is available orally and is an ingredient in some shampoo formulas.^[19]

Common use as a "cutting" agent

Inositol is also commonly used as an adulterant (or cutting agent) in many illegal drugs, such as cocaine, methamphetamine, and sometimes heroin.^[20]

Nutritional sources

Myo-inositol is naturally present in a variety of foods.^[21] According to research, foods containing the highest concentrations of myo-inositol include fruits, beans, grains, and nuts.^[21]

See also

References

External links

• Cancer Inhibition by Inositol Hexaphosphate (IP6) and Inositol: From Laboratory to Clinic (scientific publication)
• Benefits of inositol for mental health disorders, especially bipolar disorder, including references to the relevant clinical studies.
• Myo-inositol Content of Various Foods