The Healing-Promoting Properties of Selected Cyclitols-A Review

Biological Properties of Cyclitols and Their Derivatives

Cyclitols are polyhydroxy cycloalkanes, each containing at least three hydroxyls attached to a different ring carbon atom. The most important cyclitol derivatives are inositols, quercitols, conduritols and pinitols, which form a group of naturally occurring polyhydric alcohols and are widely found in plants. In addition, synthetic production of cyclitols has gained importance in recent years. Cylitols are molecules synthesized in plants as a precaution against salt or water stress. They have important functions in cell functioning as they exhibit important properties such as membrane biogenesis, ion channel physiology, signal transduction, osmoregulation, phosphate storage, cell wall formation and antioxidant activity. The biological activities of these very important molecules, obtained both synthetically and from the extraction of plants, are described in this review.

Changes in the Carbohydrate Profile in Common Buckwheat (Fagopyrum esculentum Moench) Seedlings Induced by Cold Stress and Dehydration

Plant species are sensitive to stresses, especially at the seedling stage, and they respond to these conditions by making metabolic changes to counteract the negative effects of this. The objectives of this study were to determine carbohydrate profile in particular organs (roots, hypocotyl, and cotyledons) of common buckwheat seedlings and to verify whether carbohydrate accumulation is similar or not in the organs in response to cold stress and dehydration. Roots, hypocotyl, and cotyledons of common buckwheat seedlings have various saccharide compositions. The highest concentrations of cyclitols, raffinose, and stachyose were found in the hypocotyl, indicating that they may be transported from cotyledons, although this needs further studies. Accumulation of raffinose and stachyose is a strong indicator of the response of all buckwheat organs to introduced cold stress. Besides, cold conditions reduced d-chiro-inositol content, but did not affect d-pinitol level. Enhanced accumulation of raffinose and stachyose were also a distinct response of all organs against dehydration at ambient temperature. The process causes also a large decrease in the content of d-pinitol in buckwheat hypocotyl, which may indicate its transformation to d-chiro-inositol whose content increased at that time. In general, the sucrose and its galactosides in hypocotyl tissues were subject to the highest changes to the applied cold and dehydration conditions compared to the cotyledons and roots. This may indicate tissue differences in the functioning of the protective system(s) against such threats.

Cyclitols: From Basic Understanding to Their Association with Neurodegeneration

One of the most common cyclitols found in eukaryotic cells-Myo-inositol (MI) and its derivatives play a key role in many cellular processes such as ion channel physiology, signal transduction, phosphate storage, cell wall formation, membrane biogenesis and osmoregulation. The aim of this paper is to characterize the possibility of neurodegenerative disorders treatment using MI and the research of other therapeutic methods linked to MI's derivatives. Based on the reviewed literature the researchers focus on the most common neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, Huntington's disease and Spinocerebellar ataxias, but there are also works describing other seldom encountered diseases. The use of MI, d-pinitol and other methods altering MI's metabolism, although research on this topic has been conducted for years, still needs much closer examination. The dietary supplementation of MI shows a promising effect on the treatment of neurodegenerative disorders and can be of great help in alleviating the accompanying depressive symptoms.

Neurobiology and Applications of Inositol in Psychiatry: A Narrative Review

Inositol is a natural sugar-like compound, commonly present in many plants and foods. It is involved in several biochemical pathways, most of them controlling vital cellular mechanisms, such as cell development, signaling and nuclear processes, metabolic and endocrine modulation, cell growth, signal transduction, etc. In this narrative review, we focused on the role of inositol in human brain physiology and pathology, with the aim of providing an update on both potential applications and current limits in its use in psychiatric disorders. Overall, imaging and biomolecular studies have shown the role of inositol levels in the pathogenesis of mood disorders. However, when administered as monotherapy or in addition to conventional drugs, inositol did not seem to influence clinical outcomes in both mood and psychotic disorders. Conversely, more encouraging results have emerged for the treatment of panic disorders. We concluded that, despite its multifaceted neurobiological activities and some positive findings, to date, data on the efficacy of inositol in the treatment of psychiatric disorders are still controversial, partly due to the heterogeneity of supporting studies. Therefore, systematic use of inositol in routine clinical practice cannot be recommended yet, although further basic and translational research should be encouraged.

Biosynthesis of cyclitols

Review covering up to 2021Cyclitols derived from carbohydrates are naturally stable hydrophilic substances under ordinary physiological conditions, increasing the water solubility of whole molecules in cells. The stability of cyclitols is derived from their carbocyclic structures bearing no acetal groups, in contrast to sugar molecules. Therefore, carbocycle-forming reactions are critical for the biosynthesis of cyclitols. Herein, we review naturally occurring cyclitols that have been identified to date and categorize them according to the type of carbocycle-forming enzymatic reaction. Furthermore, the cyclitol-forming enzymatic reaction mechanisms and modification pathways of the initially generated cyclitols are reviewed.

Tonoplast inositol transporters: Roles in plant abiotic stress response and crosstalk with other signals

Inositol transporters (INT) are thought to be the pivotal transporters for vital metabolites, in particular lipids, minerals, and sugars. These transporters play an important role in transitional metabolism and various signaling pathways in plants through regulating the transduction of messages from hormones, neurotransmitters, and immunologic and growth factors. Extensive studies have been conducted on animal INT, with promising outcomes. However, only few recent studies have highlighted the importance and complexity of INT genes in the regulation of plant physiology stages, including growth and tolerance to stress conditions. The present review summarizes the most recent findings concerning the role of INT or inositol genes in plant metabolism and the response mechanisms triggered by external stressors. Moreover, we highlight the emerging role of vacuoles and vacuolar INT in plant molecular transition and their related roles in plant growth and development. INTs are the essential mediators of inositol uptake and its intracellular broadcasting for various metabolic pathways where they play crucial roles. Additionally, we report evidence on Na⁺/inositol transporters, which until now have only been characterized in animals, as well as H⁺/inositol symporters and their kinetic functions and physiological role and suggest their roles and operating mode in plants. A more comprehensive understanding of the INT functioning system, in particular the coordinated movement of inositol and the relation between inositol generation and other important plant signaling pathways, would greatly advance the study of plant stress adaptation.

Beneficial In Vitro Effects of a Low Myo-Inositol Dose in the Regulation of Vascular Resistance and Protein Peroxidation under Inflammatory Conditions

Oxidative stress induces functional changes in arteries. Therefore, the effect of myo-inositol, a possible anti-inflammatory/antioxidant agent was studied on human plasma and rat thoracic arteries. Aortic rings from male Wistar rats (3 months of age) were incubated with myo-inositol (1, 10 and 100 μM, 120 min) and analyzed using the gas chromatography (GC) method. In another experiment, aortic rings were protected first with myo-inositol (1 µM, 60 min) and then subjected to a thromboxane receptor agonist (U-46619, 0.1 nM, 60 min). Therefore, these four groups under the following conditions were studied: (i) the control in the vehicle; (ii) myo-inositol; (iii) the vehicle plus U-46619; (iv) myo-inositol plus U-46619. The hemostatic parameters of human plasma and an H2O2/Fe2+ challenge for lipid and protein peroxidation were also performed. Myo-inositol was not absorbed into the pre-incubated aortic rings as measured by the GC method (0.040 µg/mg, p ≥ 0.8688). The effect of myo-inositol was more significant in the impaired arteries due to U-46619 incubation, which resulted in an improved response to acetylcholine (% Emax: 58.47 vs. 86.69), sodium nitroprusside (logEC50: −7.478 vs. −8.076), CORM-2 (% Emax: 44.08 vs. 83.29), pinacidil (logEC50: −6.489 vs. −6.988) and noradrenaline (logEC50: −7.264 vs. −6.525). This was most likely a possible response to increased nitric oxide release (×2.6-fold, p < 0001), and decreased hydrogen peroxide production (×0.7-fold, p = 0.0012). KCl-induced membrane depolarization was not modified (p ≥ 0.4768). Both the plasma protein carbonylation (×0.7-fold, p = 0.0006), and the level of thiol groups (×3.2-fold, p = 0.0462) were also improved, which was not significant for TBARS (×0.8-fold, p = 0.0872). The hemostatic parameters were also not modified (p ≥ 0.8171). A protective effect of myo-inositol was demonstrated against prooxidant damage to human plasma and rat thoracic arteries, suggesting a strong role of this nutraceutical agent on vasculature which may be of benefit against harmful environmental effects.

Novel Chemical and Biological Insights of Inositol Derivatives in Mediterranean Plants

Inositols (Ins) are natural compounds largely widespread in plants and animals. Bio-sinthetically they derive from sugars, possessing a molecular structure very similar to the simple sugars, and this aspect concurs to define them as primary metabolites, even though it is much more correct to place them at the boundary between primary and secondary metabolites. This dichotomy is well represented by the fact that as primary metabolites they are essential cellular components in the form of phospholipid derivatives, while as secondary metabolites they are involved in a plethora of signaling pathways playing an important role in the surviving of living organisms. myo-Inositol is the most important and widespread compound of this family, it derives directly from d-glucose, and all known inositols, including stereoisomers and derivatives, are the results of metabolic processes on this unique molecule. In this review, we report the new insights of these compounds and their derivatives concerning their occurrence in Nature with a particular emphasis on the plant of the Mediterranean area, as well as the new developments about their biological effectiveness.

Analyses of Antioxidative Properties of Selected Cyclitols and Their Mixtures with Flavanones and Glutathione

The conditions for determining the antioxidant properties of cyclitols (d-pinitol, l-quebrachitol, myo-, l-chiro-, and d-chiro-inositol), selected flavanones (hesperetin, naringenin, eriodictyol, and liquiritigenin) and glutathione by spectrophotometric methods—CUPRAC and with DPPH radical, and by a chromatographic method DPPH-UHPLC-UV, have been identified. Interactions of the tested compounds and their impact on the ox-red properties were investigated. The RSA (%) of the compounds tested was determined. Very low antioxidative properties of cyclitols, compared with flavanones and glutathione alone, were revealed. However, a significant increase in the determined antioxidative properties of glutathione by methyl-ether derivatives of cyclitols (d-pinitol and l-quebrachitol) was demonstrated for the first time. Thus, cyclitols seem to be a good candidate for creating drugs for the treatment of many diseases associated with reactive oxygen species (ROS) generation.

GC-MS screening and antiparasitic action of Putranjiva roxburghii leaves against sensitive and resistant strains of Leishmania donovani

Looming drug resistance cases of leishmaniasis infection are an undeniably serious danger to worldwide public health, also jeopardize the efficacy of available drugs. Besides this, no successful vaccine is available till date. Since the ancient era, many plants and their parts have been used as medicines against various ailments. Hence, the importance of drug development for new molecules against Leishmania infection is significant that is a cost-effective and safer drug preferably from the natural herbal resources. We evaluated the GC-MS screening and efficacy of Putranjiva roxburghii (PR) against the sensitive and resistant promastigotes of L. donovani. GC-MS profiling revealed that the extract was rich in myo-inositol-4-C-methyl, azulene and desulphosinigrin. Quantitative investigation of phytoconstituents confirmed that PR was rich in phenols, flavonoids and terpenoids. We found an IC50 25.61 ± 0.57 µg/mL and 29.02 ± 1.21 µg/mL of PR against sodium stibogluconate sensitive and resistant strain respectively. It was found to be safer in cytotoxicity assay and generated ROS mediated oxidative stress in the parasitic cells which was evidenced by the increased and decreased levels of superoxide radicals, lipid peroxidation products, lipid bodies and levels of thiol, plasma membrane integrity respectively. Therefore, our results support the importance of P. roxburghii as a medicinal plant against L. donovani and showed potential for exploration as an antileishmanial agent.

Osmoprotectant and antioxidant effects of new synthesized 6-(2-hydroxyethyl)cyclohex-3-enol on barley under drought stress

The aim of present study was synthesize 6-(2-hydroxyethyl)cyclohex-3-enol (11) and investigate its antioxidant properties in barley plants under drought stress. For this aim, 1,4-cyclohexadiene (7) was subjected to [2 + 2] ketene addition reaction with dichloro ketene and the chlorine atoms were reduced. After that, the cyclobutanone ring was converted to a lactone ring and the lactone ring was reduced with LiAlH₄. Subsequently, 6-(2-hydroxyethyl)cyclohex-3-enol (13) was obtained with high yield. The structures of the synthesized molecules were clarified by NMR, FTIR, GCMS spectroscopic methods. Two different methods were used to evaluate antioxidant activity of cyclohexenediol 11. One of them was DPPH radical scavenging activity which was used extensively. Also, osmoprotectant and antioxidant effects of 6-(2-hydroxyethyl)cyclohex-3-enol (13) were investigated in barley under drought stress. Drought decreased the relative water content (RWC) and water potential (WP) in barley leaves. Cyclohexenediol 11 treatment remarkably increased RWC and WP in leaves under drought conditions. Superoxide [Formula: see text] and nitric oxide (NO) accumulated under drought. In cyclohexenediol 11 treated-plants, the accumulation [Formula: see text] and NO were strongly reduced under drought conditions. Our results showed that cyclohexenediol 11 helped barley plants for maintaining water under drought stress; this makes synthetic cyclitol cyclohexenediol 11 as a good osmoprotectant candidate. Another important result in this study was the strong radical scavenging potential of cyclohexenediol 11. We think that much more comprehensive biochemical studies should be conducted to determine how cyclohexenediol 11 performs the radical scavenge role.

Production of myo-inositol: Recent advance and prospective

Myo-inositol and its derivatives have been extensively used in the pharmaceutics, cosmetics, and food and feed industries. In recent years, compared with traditional chemical acid hydrolysis, biological methods have been taken as viable and cost-effective ways to myo-inositol production from cheap raw materials. In this review, we provide a thorough overview of the development, progress, current status, and future direction of myo-inositol production (e.g., chemical acid hydrolysis, microbial fermentation, and in vitro enzymatic biocatalysis). The chemical acid hydrolysis of phytate suffers from serious phosphorous pollution and intricate product separation, resulting in myo-inositol production at a high cost. For microbial fermentation, creative strategies have been provided for the efficient myo-inositol biosynthesis by synergetic utilization of glucose and glycerol in Escherichia coli. In vitro cascade enzymatic biocatalysis is a multienzymatic transformation of various substrates to myo-inositol. Here, the different in vitro pathways design, the source of selected enzymes, and the catalytic condition optimization have been summarized and analyzed. Also, we discuss some important existing challenges and suggest several viewpoints. The development of in vitro enzymatic biosystems featuring low cost, high volumetric productivity, flexible compatibility, and great robustness could be one of the promising strategies for future myo-inositol industrial biomanufacturing.

Leaf nutrient content and transcriptomic analyses of endive (Cichorium endivia) stressed by downpour-induced waterlog reveal a gene network regulating kestose and inulin contents

Endive (Cichorium endivia L.), a vegetable consumed as fresh or packaged salads, is mostly cultivated outdoors and known to be sensitive to waterlogging in terms of yield and quality. Phenotypic, metabolic and transcriptomic analyses were used to study variations in curly- ('Domari', 'Myrna') and smooth-leafed ('Flester', 'Confiance') cultivars grown in short-term waterlog due to rainfall excess before harvest. After recording loss of head weights in all cultivars (6-35%), which was minimal in 'Flester', NMR untargeted profiling revealed variations as influenced by genotype, environment and interactions, and included drop of total carbohydrates (6-50%) and polyols (3-37%), gain of organic acids (2-30%) and phenylpropanoids (98-560%), and cultivar-specific fluctuations of amino acids (-37 to +15%). The analysis of differentially expressed genes showed GO term enrichment consistent with waterlog stress and included the carbohydrate metabolic process. The loss of sucrose, kestose and inulin recurred in all cultivars and the sucrose-inulin route was investigated by covering over 50 genes of sucrose branch and key inulin synthesis (fructosyltransferases) and catabolism (fructan exohydrolases) genes. The lowered expression of a sucrose gene subset together with that of SUCROSE:SUCROSE-1-FRUCTOSYLTRANSFERASE (1-SST) may have accounted for sucrose and kestose contents drop in the leaves of waterlogged plants. Two anti-correlated modules harbouring candidate hub-genes, including 1-SST, were identified by weighted gene correlation network analysis, and proposed to control positively and negatively kestose levels. In silico analysis further pointed at transcription factors of GATA, DOF, WRKY types as putative regulators of 1-SST.

A review of the role of inositols in conditions of insulin dysregulation and in uncomplicated and pathological pregnancy

Inositols, a group of 6-carbon polyols, are highly bioactive molecules derived from diet and endogenous synthesis. Inositols and their derivatives are involved in glucose and lipid metabolism and participate in insulin-signaling, with perturbations in inositol processing being associated with conditions involving insulin resistance, dysglycemia and dyslipidemia such as polycystic ovary syndrome and diabetes. Pregnancy is similarly characterized by substantial and complex changes in glycemic and lipidomic regulation as part of maternal adaptation and is also associated with physiological alterations in inositol processing. Disruptions in maternal adaptation are postulated to have a critical pathophysiological role in pregnancy complications such as gestational diabetes and pre-eclampsia. Inositol supplementation has shown promise as an intervention for the alleviation of symptoms in conditions of insulin resistance and for gestational diabetes prevention. However, the mechanisms behind these affects are not fully understood. In this review, we explore the role of inositols in conditions of insulin dysregulation and in pregnancy, and identify priority areas for research. We particularly examine the role and function of inositols within the maternal-placental-fetal axis in both uncomplicated and pathological pregnancies. We also discuss how inositols may mediate maternal-placental-fetal cross-talk, and regulate fetal growth and development, and suggest that inositols play a vital role in promoting healthy pregnancy.

D-chiro-inositol as a treatment in plaque psoriasis: A randomized placebo-controlled clinical trial

Cyclitols are widely available natural sugars which do not exert toxic effects. Their anti-inflammatory and antioxidant properties may be used in the treatment of psoriasis. The aim of this placebo-controlled, double-blind study was to evaluate the clinical effects of D-chiro-inositol (DCI) in mild plaque psoriasis (46 psoriatic patients and 10 healthy volunteers). Three stable psoriatic plaques were selected for evaluation in every patient. Different samples were applied on each lesion twice a day: vehiculum without an active agent, containing 1% DCI and 0.25% DCI. The lesions were assessed using the PSI, VAS scale, and the objective measurement of hydration, transepidermal water loss (TEWL), elasticity, and thickness (DermaLab Combo) at 0, 3, and 6 weeks. PSI and VAS were improved in all groups without significant statistical differences. 1% DCI sample presented the highest statistically significant increase in the hydration of 50%, but it was still significantly lower than in healthy controls. TEWL increased for 1% DCI, which was a statistically significant difference compared to 0.25% DCI and still higher than in controls. An improvement in elasticity was observed in all lesions-it was statistically significant for 1% DCI. The thickness of the lesion decreased for 1% DCI, but the change was not statistically significant. Subepidermal low-echogenic band showed a decreasing tendency in all groups, but it was not statistically significant. Favorable 1% DCI sample results indicate that it may be used as an adjuvant to the local treatment of psoriasis.

Role of Inositols and Inositol Phosphates in Energy Metabolism

Recently, inositols, especially myo-inositol and inositol hexakisphosphate, also known as phytic acid or IP6, with their biological activities received much attention for their role in multiple health beneficial effects. Although their roles in cancer treatment and prevention have been extensively reported, interestingly, they may also have distinctive properties in energy metabolism and metabolic disorders. We review inositols and inositol phosphate metabolism in mammalian cells to establish their biological activities and highlight their potential roles in energy metabolism. These molecules are known to decrease insulin resistance, increase insulin sensitivity, and have diverse properties with importance from cell signaling to metabolism. Evidence showed that inositol phosphates might enhance the browning of white adipocytes and directly improve insulin sensitivity through adipocytes. In addition, inositol pyrophosphates containing high-energy phosphate bonds are considered in increasing cellular energetics. Despite all recent advances, many aspects of the bioactivity of inositol phosphates are still not clear, especially their effects on insulin resistance and alteration of metabolism, so more research is needed.

Direct Effects of D-Chiro-Inositol on Insulin Signaling and Glucagon Secretion of Pancreatic Alpha Cells

The insulin resistance state of pancreatic α-cells seems to be related to glucagon hypersecretion in type 2 diabetes. Treatment that can improve the insulin sensitivity of α-cells could control glucagon levels in patients with diabetes mellitus. The aim of this study was to investigate the preventive role of D-chiro-inositol (DCI), which has insulin receptor-sensitizer effects on insulin signaling pathways and glucagon secretion in pancreatic α-TC1 clone 6 cells. Cells were chronically treated with palmitate to induce insulin resistance in the presence/absence of DCI. DCI treatment improved the insulin signaling pathway and restored insulin-mediated glucagon suppression in α-TC1-6 cells exposed to palmitate. These results indicate that DCI treatment prevents the insulin resistance of α-TC1-6 cells chronically exposed to palmitate. Our data provide evidence that DCI could be useful to improve the insulin sensitivity of pancreatic α-cells in diabetes treatment.

The Biomedical Uses of Inositols: A Nutraceutical Approach to Metabolic Dysfunction in Aging and Neurodegenerative Diseases

Inositols are sugar-like compounds that are widely distributed in nature and are a part of membrane molecules, participating as second messengers in several cell-signaling processes. Isolation and characterization of inositol phosphoglycans containing myo- or d-chiro-inositol have been milestones for understanding the physiological regulation of insulin signaling. Other functions of inositols have been derived from the existence of multiple stereoisomers, which may confer antioxidant properties. In the brain, fluctuation of inositols in extracellular and intracellular compartments regulates neuronal and glial activity. Myo-inositol imbalance is observed in psychiatric diseases and its use shows efficacy for treatment of depression, anxiety, and compulsive disorders. Epi- and scyllo-inositol isomers are capable of stabilizing non-toxic forms of β-amyloid proteins, which are characteristic of Alzheimer’s disease and cognitive dementia in Down’s syndrome, both associated with brain insulin resistance. However, uncertainties of the intrinsic mechanisms of inositols regarding their biology are still unsolved. This work presents a critical review of inositol actions on insulin signaling, oxidative stress, and endothelial dysfunction, and its potential for either preventing or delaying cognitive impairment in aging and neurodegenerative diseases. The biomedical uses of inositols may represent a paradigm in the industrial approach perspective, which has generated growing interest for two decades, accompanied by clinical trials for Alzheimer’s disease.

Pathogenesis of psoriasis in the "omic" era. Part III. Metabolic disorders, metabolomics, nutrigenomics in psoriasis

Psoriasis is a systemic disease that is strictly connected with metabolic disorders (insulin resistance, atherogenic dyslipidemia, arterial hypertension, and cardiovascular diseases). It occurs more often in patients with a more severe course of the disease. Obesity is specially an independent risk factor and it is associated with a worse treatment outcome because of the high inflammatory activity of visceral fatty tissue and the production of inflammatory mediators involved in the development of both psoriasis and metabolic disorders. However, in psoriasis the activation of the Th17/IL-17 and the abnormalities in the Th17/Treg balance axis are observed, but this pathomechanism does not fully explain the frequent occurrence of metabolic disorders. Therefore, there is a need to look for better biomarkers in the diagnosis, prognosis and monitoring of concomitant disorders and therapeutic effects in psoriasis. In addition, the education on the use of a proper diet as a prophylaxis for the development of the above disorders is an important element of holistic care for a patient with psoriasis. Diet may affect gene expression due to epigenetic modification which encompasses interactions of environment, nutrition and diseases. Patients with psoriasis should be advised to adopt proper diet and dietician support.

Anticancer Properties of Inositol Hexaphosphate and Inositol: An Overview

Inositol hexaphosphate (IP₆) and its parent compound myo-inositol (Ins) are active compounds from rice and other grains, with a broad spectrum of biological activities important in health and diseases. However, the most striking is the anticancer effect of IP₆ and Ins that has been actively investigated during the last decades. A consistent and reproducible anticancer action of IP₆ has been demonstrated in various experimental models. IP₆ reduces cell proliferation, induces apoptosis and differentiation of malignant cells via PI3K, MAPK, PKC, AP-1 and NF-kappaB. Very few clinical studies in humans and case reports have indicated that IP₆ is able to enhance the anticancer effect of conventional chemotherapy, control cancer metastases, and improve quality of life. Reduced burden of chemotherapy side-effects in patients receiving IP₆ alone or in combination with Ins has been reported. Because of the highly promising preclinical and emerging clinical data, large clinical trials and further mechanistic studies are warranted.

Inositols' Importance in the Improvement of the Endocrine-Metabolic Profile in PCOS

Polycystic ovary syndrome (PCOS) is one of the most common causes of infertility and metabolic problems among women of reproductive age. The mechanism of PCOS is associated with concurrent alterations at the hormonal level. The diagnosis assumes the occurrence of three interrelated symptoms of varying severity, namely ovulation disorders, androgen excess, or polycystic ovarian morphology (PCOM), which all require a proper therapeutic approach. The main symptom seems to be an increased androgen concentration, which in turn may contribute to different metabolic disorders. A number of papers have demonstrated the significant role of inositol therapy in PCOS. However, there is a lack of detailed discussion about the importance of myo-inositol (MI) and d-chiro-inositol (DCI) in reference to particular symptoms. Thus, the aim of this review is to present the effectiveness of MI and DCI treatment for PCOS symptoms. Moreover, the review is focused on analyzing the use of inositols, taking into account their physiological properties, together with the mechanism of individual PCOS symptom formation.

Health-Promoting Properties of Selected Cyclitols for Metabolic Syndrome and Diabetes

Cyclitols play a particularly important role in cell functioning because they are involved in ion channel physiology, phosphate storage, signal transduction, cell wall formation, membrane biogenesis, osmoregulation and they have antioxidant activity. They are involved in the cell membranes as a phosphatidyl myo-inositol, an inositol triphosphate precursor, which acts as a transmitter that regulates the activity of several hormones, such as follicle-stimulating hormone, thyrotropin, and insulin. The aim of this paper is to characterize the selected cyclitols: myo-inositol, D-chiro-inositol, and D-pinitol in type-2 metabolic syndrome and diabetes treatment. Results and discussion: Cyclitols have certain clinical applications in the treatment of metabolic syndromes and are considered to be an option as a dietary supplement for the treatment or prevention of gestational diabetes mellitus and type-2 diabetes. Improved metabolic parameters observed after using cyclitols, like myo-inositol, in the treatment of polycystic ovary syndrome and type-2 diabetes suggest that they may have a protective effect on the cardiovascular system. Pinitol, together with myo-inositol,maybe responsible for improving lipid profiles by reducing serum triglyceride and total cholesterol. Pinitol is also well-researched and documented for insulin-like effects. Myo-inositol, D-chiro-inositol, and D-pinitol indicate a number of therapeutic and health-promoting properties.