D-Pinitol mitigates post-traumatic stress disorder-like behaviors induced by single prolonged stress in mice through mineralocorticoid receptor antagonism

Post-traumatic stress disorder (PTSD) is a mental illness that can occur in individuals who have experienced trauma. Current treatments for PTSD, typically serotonin reuptake inhibitors, have limited effectiveness for patients and often cause serious adverse effects. Therefore, a novel class of treatment with better pharmacological profile is necessary. D-Pinitol has been reported to be effective for depression and anxiety disorders, but there are no reports associated with PTSD. In the present study, we investigated the effects of D-pinitol in a mouse model of PTSD induced by a single prolonged stress (SPS) protocol. We examined the therapeutic effects of D-pinitol on emotional and cognitive impairments in the SPS mouse model. We also investigated the effects of D-pinitol on fear memory formation. Mineralocorticoid receptor transactivation assay, Western blot, and quantitative PCR were employed to investigate how D-pinitol exerts its pharmacological activities. D-Pinitol ameliorated PTSD-like behaviors in a SPS mouse model. D-Pinitol also normalized the increased mRNA expression levels and protein levels of the mineralocorticoid receptor in the amygdala. A mineralocorticoid receptor agonist reversed the effects of D-pinitol on fear extinction and recall, and the antagonistic property of D-pinitol against the mineralocorticoid receptor was confirmed in vitro. Our findings suggest that D-pinitol could serve as a potential therapeutic agent for PTSD due to its antagonistic effect on the mineralocorticoid receptor.

Novel insights into D-Pinitol based therapies: a link between tau hyperphosphorylation and insulin resistance

Alzheimer's disease is a neurodegenerative disorder characterized by the amyloid accumulation in the brains of patients with Alzheimer's disease. The pathogenesis of Alzheimer's disease is mainly mediated by the phosphorylation and aggregation of tau protein. Among the multiple causes of tau hyperphosphorylation, brain insulin resistance has generated much attention, and inositols as insulin sensitizers, are currently considered candidates for drug development. The present narrative review revises the interactions between these three elements: Alzheimer's disease-tau-inositols, which can eventually identify targets for new disease modifiers capable of bringing hope to the millions of people affected by this devastating disease.

D-Pinitol improves cognitive dysfunction and neuronal damage induced by isoproterenol via modulation of NF-κB/BDNF/GFAP signaling in Swiss albino mice

Objectives

Neurological disorders are the world's most distressing problem. The adverse effects of current medications continue to compel scientists to seek safer, more effective, and economically affordable alternatives. In this vein, we explored the effect of D-Pinitol on isoproterenol-induced neurotoxicity in mice.

Materials and Methods

Forty-two mice were randomly distributed into 7 groups each having 6 animals. Group I; received saline. Group II; received isoproterenol (ISO) 15 mg/kg/day, s.c. for 20 days. Group III, IV; received 50 and 100 mg/kg/day/oral of D-Pinitol, respectively along with ISO for 20 days. Group V; received D-Pinitol 100 mg/kg/day/oral for 20 days. Group VI; received propranolol 20 mg/kg/day/oral and ISO for 20 days. Group VII; received propranolol 20 mg/kg/day/oral for 20 days. On the 21st day after behavioral tests, blood was collected and mice were sacrificed for various biochemical, histopathological, and immunohistochemical analyses.

Results

Chronic administration of isoproterenol caused neurotoxicity, cognitive dysfunction, and histopathological changes in the brain as evidenced by increase in GFAP, oxidative stress (via SOD, CAT, TBARS, and GSH), neuroinflammation (NF-kB, TNF-α, IL-6, and IL-10), and decrease in AchE and BDNF. Co-administration of D-Pinitol (100 mg/kg) significantly prevented these pathological alterations. The cognitive improvement was also observed through the forced swim test, elevated plus maze test, and rotarod test.

Conclusion

Our findings on D-Pinitol thus clearly established its neuroprotective role in ISO-induced neurodegeneration in Swiss albino mice.

Effect of D-pinitol on MK-801-induced schizophrenia-like behaviors in mice

Schizophrenia is a chronic brain disorder characterized by positive symptoms (delusions or hallucinations), negative symptoms (impaired motivation or social withdrawal), and cognitive impairment. In the present study, we explored whether D-pinitol could ameliorate schizophrenia-like behaviors induced by MK-801, an N-methyl-D-aspartate receptor antagonist. Acoustic startle response test was conducted to evaluate the effects of D-pinitol on sensorimotor gating function. Social interaction and novel object recognition tests were employed to measure the impact of D-pinitol on social behavior and cognitive function, respectively. Additionally, we examined whether D-pinitol affects motor coordination. Western blotting was conducted to investigate the mechanism of action of D-pinitol. Single administration of D-pinitol at 30, 100, or 300 mg/kg improved the sensorimotor gating deficit induced by MK801 in the acoustic startle response test. D-Pinitol also reversed social behavior deficits and cognitive impairments induced by MK-801 without causing any motor coordination deficits. Furthermore, D-pinitol reversed increased expression levels of pNF-kB induced by MK-801 treatment and consequently increased expression levels of TNF-α and IL-6 in the prefrontal cortex. These results suggest that D-pinitol could be a potential candidate for treating sensorimotor gating deficits and cognitive impairment observed in schizophrenia by down-regulating transcription factor NF-κB and pro-inflammatory cytokines in the prefrontal cortex.

D-Pinitol attenuates postmenopausal symptoms in ovariectomized mice

AIMS

Menopause is a natural process in women that can lead to post-menopausal syndrome with symptoms such as hot flushes, weight gain, anxiety, cognitive decline, and depression. Hormonal replacement therapy is commonly prescribed. However, it has serious adverse effects. Herbal medicinal products and isoflavones are used as alternatives. D-Pinitol found in Pinaceae and Fabaceae families has anti-inflammatory and antioxidant effects. However, it has not received as much attention as isoflavones. In this study, we investigated whether D-pinitol could alleviate post-menopausal symptoms using an ovariectomized (OVX) mouse model.

MAIN METHODS

Female ICR mice were divided into six groups: sham (vehicle), OVX (vehicle), OVX + D-pinitol (10, 30, 100 mg/kg, p.o.), and OVX + estradiol (0.5 mg/kg, s.c.). Treatment with vehicle, D-pinitol, and estradiol began at seven weeks post ovariectomy. We employed several behavioral tests, hot-flush test, and Western blot analysis.

KEY FINDINGS

We found that D-pinitol treatment (30, 100 mg/kg, p.o.) reversed cognitive dysfunction in OVX mice (novel object recognition and Y-maze test). Additionally, D-pinitol alleviated anxiety-like behaviors (elevated plus-maze) and reversed depressive-like behaviors (splash test, tail suspension test). It also normalized increased basal tail skin temperature in OVX mice. Moreover, D-pinitol administration reversed decreased expression of ERβ and synaptophysin and phosphorylation of ERK and PI3K-Akt-GSK-3β induced by OVX in the hippocampus and prefrontal cortex.

SIGNIFICANCE

These findings indicate that D-pinitol might be a promising candidate for treating post-menopausal symptoms by increasing ERβ and synaptophysin expression levels and activation of ERK or PI3K-Akt-GSK-3β signaling pathway, at least in part.

Pharmacokinetics and Endocrine Effects of an Oral Dose of D-Pinitol in Human Fasting Healthy Volunteers

The present study characterizes the oral pharmacokinetics of D-Pinitol, a natural insulin mimetic inositol, in human healthy volunteers (14 males and 11 females). D-Pinitol absorption was studied in (a) subjects receiving a single oral dose of 15 mg/kg (n = 10), or (b) 5 mg/kg pure D-Pinitol (n = 6), and (c) subjects receiving D-Pinitol as part of carbohydrate-containing carob pods-derived syrup with a 3.2% D-Pinitol (Dose of 1600 mg/subject, n = 9). The volunteers received a randomly assigned single dose of either D-Pinitol or carob pod-derived syrup. Blood samples were collected at 0, 15, 30, 45, 60, 90, 120, 180, 240, 360 and 1440 min after intake. Plasma concentration of D-Pinitol was measured and pharmacokinetic parameters obtained. The data indicate that when given alone, the oral absorption of D-Pinitol is dose-dependent and of extended duration, with a Tmax reached after almost 4 h, and a half-life greater than 5 h. When the source of D-Pinitol was a carob pods-derived syrup, Cmax was reduced to 40% of the expected based on the data of D-Pinitol alone, suggesting a reduced absorption probably because of competition with monosaccharide transport. In this group, Tmax was reached before that of D-Pinitol alone, but the estimated half-life remained the same. In the D-Pinitol groups, plasma concentrations of glucose, insulin, glucagon, ghrelin, free fatty acids, and pituitary hormones were additionally measured. A dose of 15 mg/kg of D-Pinitol did not affect glucose levels in healthy volunteers, but reduced insulin and increased glucagon and ghrelin concentrations. D-Pinitol did not increase other hormones known to enhance plasma glucose, such as cortisol or GH, which were surprisingly reduced after the ingestion of this inositol. Other pituitary hormones (gonadotropins, prolactin, and thyroid-stimulating hormone) were not affected after D-Pinitol ingestion. In a conclusion, D-Pinitol is absorbed through the oral route, having an extended half-life and displaying the pharmacological profile of an endocrine pancreas protector, a pharmacological activity of potential interest for the treatment or prevention of insulin resistance-associated conditions.

D-Pinitol-Active Natural Product from Carob with Notable Insulin Regulation

Carob is one of the major food trees for peoples of the Mediterranean basin, but it has also been traditionally used for medicinal purposes. Carob contains many nutrients and active natural products, and D-Pinitol is clearly one of the most important of these. D-Pinitol has been reported in dozens of scientific publications and its very diverse medicinal properties are still being studied. Presently, more than thirty medicinal activities of D-Pinitol have been reported. Among these, many publications have reported the strong activities of D-Pinitol as a natural antidiabetic and insulin regulator, but also as an active anti-Alzheimer, anticancer, antioxidant, and anti-inflammatory, and is also immune- and hepato-protective. In this review, we will present a brief introduction of the nutritional and medicinal importance of Carob, both traditionally and as found by modern research. In the introduction, we will present Carob’s major active natural products. The structures of inositols will be presented with a brief literature summary of their medicinal activities, with special attention to those inositols in Carob, as well as D-Pinitol’s chemical structure and its medicinal and other properties. D-Pinitol antidiabetic and insulin regulation activities will be extensively presented, including its proposed mechanism of action. Finally, a discussion followed by the conclusions and future vision will summarize this article.

Activation of PI3K/Akt Signaling Pathway in Rat Hypothalamus Induced by an Acute Oral Administration of D-Pinitol

D-Pinitol (DPIN) is a natural occurring inositol capable of activating the insulin pathway in peripheral tissues, whereas this has not been thoroughly studied in the central nervous system. The present study assessed the potential regulatory effects of DPIN on the hypothalamic insulin signaling pathway. To this end we investigated the Phosphatidylinositol-3-kinase (PI3K)/Protein Kinase B (Akt) signaling cascade in a rat model following oral administration of DPIN. The PI3K/Akt-associated proteins were quantified by Western blot in terms of phosphorylation and total expression. Results indicate that the acute administration of DPIN induced time-dependent phosphorylation of PI3K/Akt and its related substrates within the hypothalamus, indicating an activation of the insulin signaling pathway. This profile is consistent with DPIN as an insulin sensitizer since we also found a decrease in the circulating concentration of this hormone. Overall, the present study shows the pharmacological action of DPIN in the hypothalamus through the PI3K/Akt pathway when giving in fasted animals. These findings suggest that DPIN might be a candidate to treat brain insulin-resistance associated disorders by activating insulin response beyond the insulin receptor.

D-Pinitol from Ceratonia siliqua Is an Orally Active Natural Inositol That Reduces Pancreas Insulin Secretion and Increases Circulating Ghrelin Levels in Wistar Rats

To characterize the metabolic actions of D-Pinitol, a dietary inositol, in male Wistar rats, we analyzed its oral pharmacokinetics and its effects on (a) the secretion of hormones regulating metabolism (insulin, glucagon, IGF-1, ghrelin, leptin and adiponectin), (b) insulin signaling in the liver and (c) the expression of glycolytic and neoglucogenesis enzymes. Oral D-Pinitol administration (100 or 500 mg/Kg) resulted in its rapid absorption and distribution to plasma and liver compartments. Its administration reduced insulinemia and HOMA-IR, while maintaining glycaemia thanks to increased glucagon activity. In the liver, D-Pinitol reduced the key glycolytic enzyme pyruvate kinase and decreased the phosphorylation of the enzymes AKT and GSK-3. These observations were associated with an increase in ghrelin concentrations, a known inhibitor of insulin secretion. The profile of D-Pinitol suggests its potential use as a pancreatic protector decreasing insulin secretion through ghrelin upregulation, while sustaining glycaemia through the liver-based mechanisms of glycolysis control.