Inositol (myo-inositol) , is a carbocyclic sugar that is abundant in the brain and other mammalian tissues.
Myo-inositol mediates cell signal transduction in response to a variety of hormones, neurotransmitters, and growth factors and participates in osmoregulation.
Inositol is a naturally occurring substance that belongs to the vitamin B complex family.
It is often referred to as vitamin B8, although it is not officially recognized as a vitamin.
Inositol is found in various forms, with myo-inositol being the most common and biologically active form.
Inositol plays several important roles in the body:
Cell Signaling: Inositol is a precursor for the synthesis of inositol phosphates, which act as secondary messengers in cellular signaling pathways. These pathways are involved in various cellular functions such as cell growth, differentiation, and communication.
Neurotransmitter Signaling: Inositol is also involved in neurotransmitter signaling in the brain. It is a component of phosphatidylinositol, which is critical for the proper functioning of neurotransmitter receptors and the release of various neurotransmitters.
Insulin Sensitivity: Inositol has been studied for its potential benefits in improving insulin sensitivity and managing conditions like polycystic ovary syndrome (PCOS) and metabolic syndrome.
It may aid in regulating glucose metabolism and lipid levels.
4. Mental Health: Inositol has been investigated for its potential role in mental health conditions such as depression, anxiety, and obsessive-compulsive disorder (OCD).
It may have a positive impact on mood regulation and symptoms associated with these conditions.
5. Lipid Metabolism: Inositol is involved in the breakdown of fats in the body.
It assists in the emulsification of dietary fats in the digestive system and plays a role in transporting fats out of the liver.
It is a sugar alcohol with half the sweetness of sucrose.
It is made naturally in the human body from glucose.
A human kidney makes about two grams per day, but other tissues synthesize it as well.
It has the highest concentration is in the brain, where it plays an important role in making other neurotransmitters and some steroid hormones bind to their receptors.
myo-Inositol plays an important role as the structural basis for a number of secondary messengers in eukaryotic cells, inositol phosphates.
Inositol serves as an important component of the structural lipids phosphatidylinositol (PI) and its various phosphates, the phosphatidylinositol phosphate (PIP) lipids.
Inositol or its phosphates and associated lipids are found in many foods, in particular fruit, especially cantaloupe and oranges.
In plants, the hexaphosphate of inositol, phytic acid, and phytates, serve as phosphate stores in seed, for example in nuts and beans.
Phytic acid also occurs in cereals with high bran content.
myo-Inositol was once considered a member of the vitamin B complex, called Vitamin B8, in this.
However, because it is produced by the human body from glucose, it is not an essential nutrient.
myo-Inositol is synthesized from glucose 6-phosphate (G6P) in two steps.
Most inositol is synthesized in the kidneys, followed by testicles, typically in amounts of a few grams per day.
Inositol, phosphatidylinositol and some of their mono- and polyphosphates function as secondary messengers in a number of intracellular signal transduction pathways.
They are involved in a number of biological processes, including:
Insulin signal transduction
Cytoskeleton assembly
Nerve guidance
Intracellular calcium (Ca2+) concentration control
Cell membrane potential maintenance
Breakdown of fats
Gene expression
Phosphatidylinositol 4,5-bisphosphate (PIP2) is stored in cellular membranes until it is released by a number of signalling proteins and transformed into various secondary messengers, for example diacylglycerol and inositol triphosphate.
Inositol hexaphosphate, also called phytic acid or IP6, is a phytochemical and the principal storage form of phosphorus in many plant tissues, especially bran and seed.
Phosphorus and inositol in phytate form are not generally bioavailable because of a lack the digestive enzyme phytase required to remove the phosphate groups.
Ruminants are readily able to digest phytate because of the phytase produced by microorganisms in the rumen.
Phytic acid also chelates important minerals such as calcium, magnesium, iron, and zinc, making them unabsorbable, and contributing to mineral deficiencies in people whose diets rely highly on bran and seeds for their mineral intake, such as occurs in developing countries.
Inositol nitrate is used to gelatinize nitrocellulose in many modern explosives and solid rocket propellants.
Inositol has been found to have modest to moderate effects in patients with panic disorder or obsessive-compulsive disorder.
Myo-inositol helps prevent neural tube defects with particular efficacy in combination with folic acid.
Inositol is considered a safe and effective treatment for polycystic ovary syndrome (PCOS).
It works by increasing insulin sensitivity, which helps to improve ovarian function and reduce hyperandrogenism.
It has been shown to reduce the risk of metabolic disease in people with PCOS.
In addition, it has a role as a FSH second messenger, and myo-inositol is effective in restoring FSH/LH ratio and menstrual cycle regularization.
myo-Inositol’s role as FSH second messenger leads to a correct ovarian follicle maturation and consequently to a higher oocyte quality.
Improving the oocyte quality in both women with or without PCOS, myo-inositol can be considered as a possible approach for increasing the chance of success in assisted reproductive technologies.
D-chiro-inositol can impair oocyte quality in a dose-dependent manner.
The high level of DCI seems to be related to elevated insulin levels retrieved in about 70% of PCOS women.
Insulin stimulates the irreversible conversion of myo-inositol to D-chiro-inositol causing a drastic reduction of myo-inositol.
myo-Inositol depletion is particularly damaging to ovarian follicles because it is involved in FSH signaling, which is impaired due to myo-inositol depletion.
The use of inositols in PCOS has an efficacy higher than 70% with a strong safety profile.
About 30% of patients could show as inositol-resistant.
Phytic acid has potential uses in endodontics, adhesive, preventive, and regenerative dentistry, as it improves the characteristics and performance of dental materials.
It is used as an adulterant or cutting agent for many illegal drugs, such as cocaine, methamphetamine, sometimes heroin.
myo-Inositol is naturally present in a variety of foods.
Foods containing high concentrations of myo-inositol and its compounds include fruits, beans, grains, and nuts.
Fruits and especially cantaloupe, contain the highest amounts of myo-inositol.
Myo-inositol is also present in beans, nuts, and grains, however, these contain large amounts of myo-inositol in the phytate form, which is not bioavailable without transformation by phytase enzymes.
Bacillus subtilis produces the fermented food natto, produces phytase enzymes that may convert phytic acid to a more bioavailable form of inositol polyphosphate in the gut.
Additionally, Bacteroides species in the gut secrete vesicles containing an active enzyme which converts the phytate molecule into bioavailable phosphorus and inositol polyphosphate, which is an important signaling molecule in the human body.
myo-Inositol can also be found as an ingredient in energy drinks, in conjunction with or as a substitute for glucose.
In humans, myo-inositol is naturally made from glucose-6-phosphate through enzymatic dephosphorylation.