Pinitol Research Articles

D-Pinitol Improves Diabetic Sarcopenia by Regulation of the Gut Microbiome, Metabolome, and Proteome in STZ-Induced SAMP8 Mice.

d-Pinitol (DP) is primarily found in Vigna sinensis, which has been shown to have hypoglycemic and protective effects on target organs. However, the mechanism of DP in treating diabetic sarcopenia (DS) is still unclear. To explore the underlying mechanism of DS and the protective targets of DP by high-throughput analysis of 16S rRNA gene, metabolome, and the proteome. Streptozotocin-induced SAMP8 mice were intragastrically administrated DP (150 mg/kg) for 8 weeks. Fecal 16S rRNA gene sequencing and gastrocnemius muscle metabolomic and proteomic analyses were completed to investigate the gut-muscle axis interactions. DP significantly alleviated the muscle atrophy in diabetic mice. Dysfunction of the gut microbiota was observed in the DS mice. DP significantly reduced the Parabacteroides, Akkermansia, and Enterobacteriaceae, while it increased Lachnospiraceae_NK4A136. Metabolome and proteome revealed that 261 metabolites and 626 proteins were significantly changed in the gastrocnemius muscle of diabetic mice. Among these, DP treatment restored 44 metabolites and 17 proteins to normal levels. Functional signaling pathways of DP-treated diabetic mice included nucleotide metabolism, β-alanine, histidine metabolism, ABC transporters, and the calcium signaling pathway. We systematically explored the molecular mechanism of DS and the protective effect of DP, providing new insights that may advance the treatment of sarcopenia.

The regulation of MFG-E8 on the mitophagy in diabetic sarcopenia via the HSPA1L-Parkin pathway and the effect of D-pinitol.

Diabetic sarcopenia is a disease-related skeletal muscle disorder that causes progressive symptoms. The complete understanding of its pathogenesis is yet to be unravelled, which makes it difficult to develop effective therapeutic strategies. This study investigates how MFG-E8 affects mitophagy and the protective role of D-pinitol (DP) in diabetic sarcopenia. In vivo, streptozotocin-induced diabetic SAM-R1 (STZ-R1) and SAM-P8 (STZ-P8) mice (16-week-old) were used, and STZ-P8 mice were administrated of DP (150mg/kg per day) for 6weeks. Gastrocnemius muscles were harvested for histological analysis including transmission electron microscopy. Proteins were evaluated via immunohistochemistry (IHC), immunofluorescence (IF), and western blotting (WB) assay. In vitro, advanced glycation end products (AGEs) induced diabetic and D-galactose (DG) induced senescent C2C12 models were established and received DP, MFG-E8 plasmid (Mover)/siRNA (MsiRNA), or 3-MA/Torin-1 intervention. Proteins were evaluated by IF and WB assay. Immunoprecipitation (IP) and co-immunoprecipitation (CO-IP) were used for hunting the interacted proteins of MFG-E8. In vivo, sarcopenia, mitophagy deficiency, and up-regulated MFG-E8 were confirmed in the STZ-P8 group. DP exerted protective effects on sarcopenia and mitophagy (DP+STZ-P8 vs. STZ-P8; all P<0.01), such as increased lean mass (8.47±0.81g vs. 7.08±1.64g), grip strength (208.62±39.45g vs. 160.87±26.95g), rotarod tests (109.7±11.81s vs. 59.3±20.97s), muscle cross-sectional area (CSA) (1912.17±535.61μm2 vs. 1557.19±588.38μm2), autophagosomes (0.07±0.02 per μm2 vs. 0.02±0.01 per μm2), and cytolysosome (0.07±0.03 per μm2 vs. 0.03±0.01 per μm2). DP down-regulated MFG-E8 in both serum (DP+STZ-P8: 253.19±34.75pg/mL vs. STZ-P8: 404.69±78.97pg/mL; P<0.001) and gastrocnemius muscle (WB assay. DP+STZ-P8: 0.39±0.04 vs. STZ-P8: 0.55±0.08; P<0.01). DP also up-regulated PINK1, Parkin and LC3B-II/I ratio, and down-regulated P62 in gastrocnemius muscles (all P<0.01). In vitro, mitophagy deficiency and MFG-E8 up-regulation were confirmed in diabetic and senescent models (all P<0.05). DP and MsiRNA down-regulated MFG-E8 and P62, and up-regulated PINK1, Parkin and LC3B-II/I ratio to promote mitophagy as Torin-1 does (all P<0.05). HSPA1L was confirmed as an interacted protein of MFG-E8 in IP and CO-IP assay. Mover down-regulated the expression of Parkin via the HSPA1L-Parkin pathway, leading to mitophagy inhibition. MsiRNA up-regulated the expression of PINK1 via SGK1, FOXO1, and STAT3 phosphorylation pathways, leading to mitophagy stimulation. MFG-E8 is a crucial target protein of DP and plays a distinct role in mitophagy regulation. DP down-regulates the expression of MFG-E8, reduces mitophagy deficiency, and alleviates the symptoms of diabetic sarcopenia, which could be considered a novel therapeutic strategy for diabetic sarcopenia.

D-pinitol alleviates diabetic cardiomyopathy by inhibiting the optineurin-mediated endoplasmic reticulum stress and glycophagy signaling pathway.

Diabetic cardiomyopathy (DCM) is an important complication resulting in heart failure and death of diabetic patients. However, there is no effective drug for treatments. This study investigated the effect of D-pinitol (DP) on cardiac injury using diabetic mice and glycosylation injury of cardiomyocytes and its molecular mechanisms. We established the streptozotocin-induced SAMR1 and SAMP8 mice and DP (150 mg/kg/day) intragastrically and advanced glycation end-products (AGEs)-induced H9C2 cells. H9C2 cells were transfected with optineurin (OPTN) siRNA and overexpression plasmids. The metabolic disorder indices, cardiac dysfunction, histopathology, immunofluorescence, western blot, and immunoprecipitation were investigated. Our results showed that DP reduced the blood glucose and AGEs, and increased the expression of heart OPTN in diabetic mice and H9C2 cells, thereby inhibiting the endoplasmic reticulum stress (GRP78, CHOP) and glycophagy (STBD1, GABARAPL1), and alleviating the myocardial apoptosis and fibrosis of DCM. The expression of filamin A as an interaction protein of OPTN downregulated by AGEs decreased OPTN abundance. Moreover, OPTN siRNA increased the expression of GRP78, CHOP, STBD1, and GABARAPL1 and inhibited the expression of GAA via GSK3β phosphorylation and FoxO1. DP may be helpful to treat the onset of DCM. Targeting OPTN with DP could be translated into clinical application in the fighting against DCM.

Integrated proteomics and metabolomics analysis of D-pinitol function during hippocampal damage in streptozocin-induced aging-accelerated mice.

Diabetes can cause hippocampal damage and lead to cognitive impairment. Diabetic cognitive impairment (DCI) is a chronic complication of diabetes associated with a high disability rate; however, its pathogenesis and therapeutic targets are unclear. We aimed to explore the mechanism of hippocampal damage during diabetes and evaluate the potential role of D-pinitol (DP) in protecting hippocampal tissue and improving cognitive dysfunction. DP (150 mg/kg/day) was administered intragastrically to streptozocin-induced aging-accelerated mice for 8 weeks. Hippocampal tissues were examined using tandem mass tag (TMT)-based proteomics and liquid chromatography-mass spectrometry (LC-MS)/MS-based non-targeted metabolomic analysis. Differentially expressed proteins (DEPs) and differentially regulated metabolites (DRMs) were screened for further analysis, and some DEPs were verified using western blotting. Our results showed that 329 proteins had significantly altered hippocampal expression in untreated diabetic mice (DM), which was restored to normal after DP treatment in 72 cases. In total, 207 DRMs were identified in the DM group, and the expression of 32 DRMs was restored to normal post-DP treatment. These proteins and metabolites are involved in metabolic pathways (purine metabolism, arginine and proline metabolism, and histidine metabolism), actin cytoskeleton regulation, oxidative phosphorylation, and Rap1-mediated signaling. Our study may help to better understand the mechanism of diabetic hippocampal damage and cognitive impairment and suggest a potential therapeutic target.

D-pinitol ameliorated H2O2-induced oxidative damage in PC12 cells and prolonged the lifespan by IIS pathway in Caenorhabditis elegans

D-pinitol (DP) has been extensively regarded as the main active component of legumes for anti-aging. In this study, we intended to explore the anti-aging mechanism of DP, utilizing computer modeling techniques. The results demonstrated that DP significantly delayed H2O2-induced cellular senescence. Model PC12 cells treated with DP exhibited increased cell viability, increased antioxidant enzyme activity (SOD, CAT), and reduced ROS and MDA levels. Furthermore, DP was discovered to have a positive effect on healthy longevity. In C. elegans, DP treatment enhanced lifespan, stress capacity, antioxidant capacity (T-SOD/CAT/GSH-Px/MDA/ROS), and altered aging-related indicators of lipofuscin accumulation, pharyngeal pump rate, motility, and reproduction. Moreover, DP could reduce the toxicity Aβ in transgenic C. elegans CL4176, CL2355, and CL2331. Further mechanistic studies indicated DP increased transcription factor (daf-16, skn-1, hsf-1) expression of insulin/insulin-like growth factor-1 signaling (IIS) pathway. As expected, DP also extended the downstream target genes of the three transcription factors (sod-3, ctl-1, ctl-2, gst-4, hsp-16.1, and hsp-16.2). Further mutant lifespan experiments, network pharmacology, and molecular docking revealed that DP might be life-extending through the IIS pathway. DP deserves extensive investigation and development as a potential anti-aging drug in the future.

D-Chiro-Inositol extends the lifespan of male Drosophila melanogaster better than d-Pinitol through insulin signaling and autophagy pathways.

d-Pinitol (DP) is the methylated product of d-Chiro-Inositol (DCI), which is one of the nine isomers of inositol with optical activity. Both substances possess antioxidant activity. This study was conducted to investigate and compare the antioxidant and life-prolonging effects of DCI and DP on male Drosophila melanogaster. Results showed that DCI and DP prolonged the lifespan and improved the climbing, anti-stress, and antioxidant activities. After treatment with DCI and DP, intestinal homeostasis was improved and the abnormal proliferation of intestinal stem cells (ISCs) was attenuated. Furthermore, real-time PCR revealed downregulated expression levels of PI3K and Akt and upregulated expression levels of Dilp5 and FOXO, which consequently activated Atg1, Atg5, Atg8a, and Atg8b and increased the number of lysosomes. Altogether, DCI exerts a slightly better effect than DP based on various indicators. RNAi D. melanogaster lifespan and molecular docking results further suggested that DCI and DP could prolong longevity through insulin signaling (IIS) and autophagy pathways.

Phosphoproteomics analysis of diabetic cardiomyopathy in aging-accelerated mice and effects of D-pinitol.

The molecular mechanisms of diabetic cardiomyopathy (DCM) development and D-pinitol (DP) in its treatment remain unclear. The present study is to explore the underlying mechanism of DCM in an elderly diabetic mouse model and to seek the protective targets of DP by phosphoproteomics. We used streptozotocin to induce diabetes in SAMP8 and DP (150mg/kg/day) intragastrically administrated to diabetic mice for 8weeks. The heart tissues were harvested for label-free phosphoproteomic analysis from diabetic mice. Some differentially regulated phosphorylation sites were confirmed by parallel reaction monitoring. Our results showed that 612 phosphorylation sites on 454 proteins had their phosphorylation levels significantly changed in the heart of untreated diabetic mice (DM). Of these phosphorylation sites, 216 phosphorylation sites on 182 proteins were normalized after DP treatment. We analyzed the functional signaling pathways in the heart of DP treated diabetic mice (DMT), including glucagon signaling pathway, insulin signaling pathway, mitophagy, apoptosis, and longevity regulating pathway. Two consensus motifs identified were targeted by Src and epidermal growth factor receptor between DMT and DM groups. Our study might help to better understand the mechanism of DCM, provide novel targets for estimating the protective effects of DP.

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.

Effects of D-pinitol on myocardial apoptosis and fibrosis in streptozocin-induced aging-accelerated mice.

Diabetic cardiomyopathy (DCM) causes heart failure and increases the mortality in diabetic patients. Myocardial apoptosis and fibrosis are the main features of DCM and aging. The aim is to study the underlying mechanism of D-pinitol (DP) on myocardial apoptosis and fibrosis in an elderly diabetic mouse model. The diabetic model was established by SAMP-8 mice that were injected with streptozotocin daily for five consecutive days. The mice were administrated of DP (150mgkg-1 day-1 ) by gavage for 10weeks. The common metabolic disorder indices, cardiac dysfunction, oxidative stress, myocardial apoptosis and fibrosis, and PI3K/Akt/mTOR pathway were investigated. Our findings suggested that DP has a protective effect on DCM, which may be related to regulating oxidative stress, and PI3K/Akt/mTOR pathway involving cardiac fibrosis and apoptosis. DP may be a novel clinical application in fighting against DCM. PRACTICAL APPLICATIONS: D-pinitol (DP) was found in large quantities in soybean and legume foods. DP has a variety of functions, including hypoglycemic, anti-oxidation, anti-inflammatory, cardioprotective, and anti-tumor activity. We used the streptozotocin-induced SAMP8 mice as the diabetic model and treated with DP. We found that DP can improve cardiac dysfunction and inhibits the oxidative stress, myocardial apoptosis and fibrosis. DP has a significant effect on diabetic cardiomyopathy (DCM). The molecular mechanisms are related to regulating oxidative stress, and PI3K/Akt/mTOR pathway involving cardiac fibrosis and apoptosis. DP can prevent and/or delay the onset of DCM.

The protective mechanism of D-pinitol on advanced glycation end products-induced proliferation and migration in vascular smooth muscle cells

Objective To investigate the effect and its mechanism of D-pinitol on advanced glycation end products(AGEs)-induced proliferation and migration in mouse aortic vascular smooth muscle cells(VSMC). Methods VSMCs were isolated from mouse aorta and cultured in vitro.Effects of different concentrations of D-pinitol on proliferation and migration of VSMCs were observed by using the AGEs-induced glycosylation injury model of VSMCs.Cell proliferation and migration were detected by CCK-8 assay and cell scratch, respectively.The protein expression levels of transforming growth factor-β1(TGF-β1), p-smad2, p-smad3 and asporin were determined by Western blot. Results Compared with control group, AGEs group showed the increased protein expression levels of asporin, TGF-β1, p-smad2 and p-smad3(40.06±4.50 vs.17.47±0.57), (55.25±2.07 vs.14.42±2.07), (0.97±0.02 vs.0.47±0.02), (0.45±0.01 vs.0.26±0.02), all P<0.01.Compared to AGEs group, D-pinitol group could inhibit the cell proliferation and migration and cause dose-dependent decreases of protein expressions of TGF-β1, p-smad2, p-smad3 and asporin(P<0.05 or P<0.01). Conclusions D-pinitol can inhibit AGEs-induced cell proliferation and migration in mouse aortic VSMCs.Asporin may participate in the VSMCs extracellular matrix remodeling via TGF-β/smad pathway. Key words: D-pinitol; Muscle, smooth, vascular; Glycosylation end products, advanced; Extracellular matrix

D-pinitol mitigates tumor growth by modulating interleukins and hormones and induces apoptosis in rat breast carcinogenesis through inhibition of NF-κB

Breast cancer is the most prevalent malignant neoplasm in the world, and chemoprevention through dietary intervention strategy is an emerging option to reduce the incidence. D-pinitol (DP), a major component of soya bean, possesses attractive biological actions. We have investigated whether D-pinitol have an effect on tumor growth in vivo against 7,12-dimethylbenz(a)anthracene (DMBA)-initiated rat mammary carcinogenesis and investigated its mechanism of action. Tumors were induced in Sprague-Dawley (SD) rats by a gastric dose of 20 mg/kg DMBA, and after 13 weeks of induction period, the rats were orally administered with D-pinitol for 45 days. At the end of the assay, animals in carcinogen control group prompted a tumor incidence of 100 % and developed a tumor volume of 8.35 ± 0.56, which was significantly reduced to 5.74 ± 0.32 for the animals treated with D-pinitol. The D-pinitol treatment not only decreased the tumor volume but also further examination revealed that tumors from animals that received D-pinitol reduced nuclear factor kappa B (NF-κB) activation which in turn results in modulation of its downstreaming p53 and proteins of caspase-3 family. Bcl-2 expression and caspase-3 activation were also decreased after D-pinitol supplementation leading to induction of apoptosis and finally cell death. Furthermore, the status of the inflammatory cytokines such as tumor necrosis factor-α (TNF-α), interleukin (IL)-2, IL-6, and tumor markers, lipid profile, and hormones was also significantly declined up on D-pinitol administration. Thus, it reveals the collective involvement of the above-mentioned parameters along with NF-κB signaling through which D-pinitol induces apoptosis and subsequently suppresses breast cancer during DMBA-induced rat breast carcinogenesis.

Chemical constituents of Allophylus africanus

Four new compounds, alloeudesmenol (1), hanocokinoside (3), allotaraxerolide (4), and alloaminoacetaldehyde (5), together with two known compound, stigmastane-3β,4β-diol (2) and pinitol 6 (a and b) were isolated and identified from the whole plant of Allophylus africanus.

Biochemistry and physiology of raffinose family oligosaccharides and galactosyl cyclitols in seeds

Raffinose family oligosaccharides (RFOs) are of almost ubiquitous occurrence in plant seeds. They accumulate during seed development and disappear rapidly during germination. The biosynthesis of raffinose, the first member of the series, proceeds by addition of a galactosyl unit to sucrose. Galactinol, a galactosyl derivative of myo-inositol, acts as a galactosyl donor. It is synthesized from UDP-D-galactose and myo-inositol. Stachyose, verbascose and ajugose, the next higher RFOs, are either synthesized by galactinol-dependent galactosyltransferases or by transfer of galactosyl units between two RFO molecules. In seeds, the metabolism of methylated inositols, such as D-ononitol and D-pinitol, is linked with the RFO pathway. In contrast to myoinositol, these cyclitols are galactosylated by transfer of galactosyl residues from galactinol and not from UDP-Dgalactose. However, the resulting galactosyl cyclitols can replace galactinol as galactosyl donors for the biosynthesis of stachyose. These recently discovered branches of the RFO pathway are active in seeds of a range of crop species, especially in legumes. We focus here on the biochemistry and molecular biology of the enzymes of RFO and galactosyl cyclitol biosynthesis. The metabolic control and hormonal regulation of the pathway during seed development and germination is discussed. The controversial role of � -galactosidases, which are believed to hydrolyse RFOs during germination, is reviewed critically.

Glass Formation by Galactopinitol with Other Sugars and Their Ability to Protect Phospholipid Vesicles from Drying Damage

A galactopinitol (Galpi), O-α-D-galactopyranosyl-(1→1)-3-O-methyl-D-chiro-inositol, together with sucrose, raffinose, and stachyose were extracted from seeds of Leucaena leucocephala (Lam.) de Wit and characterized for glass formation and phospholipid vesicle stabilization during dehydration. Raffinose, stachyose, and Galpi were found to have good glass forming properties, and their glass transition temperatures (Tgs) were 67.4, 66.4, and 33.40℃, respectively. The Tgs were much higher than those of glucose and sucrose. The Tg for a mass ratio mixture of Galpi and sucrose of 0.3/1 was greater than 0 and was similar to that of the same ratio mixture of raffinose to sucrose, indicating that Galpi as well as oligosaccharides plays an important role in glass formation. The mixture of Galpi plus sucrose appeared to protect phospholipid vesicles during dehydration and rehydration to the same degree as did raffinose or the stachyose plus sucrose mixture. The percent protection (leakage of isocitrate) of vesicles provided by sucrose, Galpi, raffinose, and stachyose was in the approximate range of 38 to 48%. The results suggest that Galpi may prevent cellular collapse during the desiccation of leucaena seeds and function much the same as oligosaccharides.