Overview of Inositol and Inositol Phosphates on Chemoprevention of Colitis-Induced Carcinogenesis

Impact of milling on the nutrients and anti-nutrients in browntop millet (Urochloa ramosa) and its milled fractions: evaluation of their flour functionality

BACKGROUND

Browntop millet has gained popularity in recent years owing to its nutritional superiority and health benefits. However, the usage of browntop millet flours as ingredients in composite flours and functional foods is constrained due to a lack of information regarding the grain composition and its flour functionality. Therefore, the distribution of nutrients, anti-nutrients in browntop millet milled fractions and their flour functionality was evaluated in comparison to whole grain flour.

RESULTS

Bran fraction comprised the highest protein (13.7%) and fat contents (27%) among other fractions. Pearling of dehulled grains considerably reduced phytic acid, saponins and flatulence-causing oligosaccharides in pearled grain flours. Besides, this led to the enrichment of soluble fibre, minerals, phenolics and trypsin inhibitors in bran fraction. Milling also impacted flour functionality. Despite its lower water holding ability, dehulled grain flour exhibited significantly higher oil absorption capacity than whole grain flour due to the removal of fibre-rich hull fraction. Although emulsion (45.2%) and foaming capacities (12.5%) were superior in bran flour, foam stability was greater in pearled grain flours.

CONCLUSION

These findings suggest the potential utilisation of browntop millet milled flours as ingredients in the development of distinct food formulations and as partial substitutes to wheat flour in confectionary and bakery products. © 2024 Society of Chemical Industry.

Activated Inositol Phosphate, Substrate for Synthesis of Prostaglandylinositol Cyclic Phosphate (Cyclic PIP)-The Key for the Effectiveness of Inositol-Feeding

The natural cyclic AMP antagonist, prostaglandylinositol cyclic phosphate (cyclic PIP), is biosynthesized from prostaglandin E (PGE) and activated inositol phosphate (n-Ins-P), which is synthesized by a particulate rat-liver-enzyme from GTP and a precursor named inositol phosphate (pr-Ins-P), whose 5-ring phosphodiester structure is essential for n-Ins-P synthesis. Aortic myocytes, preincubated with [3H] myo-inositol, synthesize after angiotensin II stimulation (30 s) [3H] pr-Ins-P (65% yield), which is converted to [3H] n-Ins-P and [3H] cyclic PIP. Acid-treated (1 min) [3H] pr-Ins-P co-elutes with inositol (1,4)-bisphosphate in high performance ion chromatography, indicating that pr-Ins-P is inositol (1:2-cyclic,4)-bisphosphate. Incubation of [3H]-GTP with unlabeled pr-Ins-P gave [3H]-guanosine-labeled n-Ins-P. Cyclic PIP synthase binds the inositol (1:2-cyclic)-phosphate part of n-Ins-P to PGE and releases the [3H]-labeled guanosine as [3H]-GDP. Thus, n-Ins-P is most likely guanosine diphospho-4-inositol (1:2-cyclic)-phosphate. Inositol feeding helps patients with metabolic conditions related to insulin resistance, but explanations for this finding are missing. Cyclic PIP appears to be the key for explaining the curative effect of inositol supplementation: (1) inositol is a molecular constituent of cyclic PIP; (2) cyclic PIP triggers many of insulin's actions intracellularly; and (3) the synthesis of cyclic PIP is decreased in diabetes as shown in rodents.

The myo-inositol biosynthesis rate-limiting enzyme ISYNA1 suppresses the stemness of ovarian cancer via Notch1 pathway

Cancer stem cells (CSCs) play a central role in ovarian cancer (OC), understanding regulatory mechanisms governing their stemness is critical. Here, we report ISYNA1, the rate-limiting enzyme in myo-inositol biosynthesis, as a suppressor of OC regulating cancer stemness. We identified ISYNA1 as a differentially expressed gene in normal ovary and ovarian cancer tissues, as well as OC cells and OCSCs. Low ISYNA1 expression correlated with poor prognosis in OC patients. In addition, ISYNA1 was negatively correlated with CSC markers, and ISYNA1-related pathways were enriched in Wnt, Notch, and other critical cancer pathways. ISYNA1 deficiency promoted OC cell growth, migration, and invasion ability in vitro and in vivo. Knockdown of ISYNA1 increased stemness of OC cells, including self-renewal, CSC markers expression, ALDH activity, and proportion of CD44⁺/CD117⁺ CSCs. Conversely, ectopic overexpression of ISYNA1 suppresses cell proliferation, migration, invasion and stemness of OC cells. Mechanistically, ISYNA1 inhibits OC stemness by regulating myo-inositol to suppress Notch1 signaling. In summary, these data provide evidence that ISYNA1 act as a tumor suppressor in OC and a regulator of stemness, providing insight into potentially targetable pathways for ovarian cancer therapy.

Inositol in Disease and Development: Roles of Catabolism via myo-Inositol Oxygenase in Drosophila melanogaster

Inositol depletion has been associated with diabetes and related complications. Increased inositol catabolism, via myo-inositol oxygenase (MIOX), has been implicated in decreased renal function. This study demonstrates that the fruit fly Drosophila melanogaster catabolizes myo-inositol via MIOX. The levels of mRNA encoding MIOX and MIOX specific activity are increased when fruit flies are grown on a diet with inositol as the sole sugar. Inositol as the sole dietary sugar can support D. melanogaster survival, indicating that there is sufficient catabolism for basic energy requirements, allowing for adaptation to various environments. The elimination of MIOX activity, via a piggyBac WH-element inserted into the MIOX gene, results in developmental defects including pupal lethality and pharate flies without proboscises. In contrast, RNAi strains with reduced levels of mRNA encoding MIOX and reduced MIOX specific activity develop to become phenotypically wild-type-appearing adult flies. myo-Inositol levels in larval tissues are highest in the strain with this most extreme loss of myo-inositol catabolism. Larval tissues from the RNAi strains have inositol levels higher than wild-type larval tissues but lower levels than the piggyBac WH-element insertion strain. myo-Inositol supplementation of the diet further increases the myo-inositol levels in the larval tissues of all the strains, without any noticeable effects on development. Obesity and blood (hemolymph) glucose, two hallmarks of diabetes, were reduced in the RNAi strains and further reduced in the piggyBac WH-element insertion strain. Collectively, these data suggest that moderately increased myo-inositol levels do not cause developmental defects and directly correspond to reduced larval obesity and blood (hemolymph) glucose.

Investigating Genetic Determinants of Plasma Inositol Status in Adult Humans

BACKGROUND

Myo-inositol (MI) is incorporated into numerous biomolecules, including phosphoinositides and inositol phosphates. Disturbance of inositol availability or metabolism is associated with various disorders, including neurological conditions and cancers, whereas supplemental MI has therapeutic potential in conditions such as depression, polycystic ovary syndrome, and congenital anomalies. Inositol status can be influenced by diet, synthesis, transport, utilization, and catabolism.

OBJECTIVES

We aimed to investigate potential genetic regulation of circulating MI status and to evaluate correlation of MI concentration with other metabolites.

METHODS

GC-MS was used to determine plasma MI concentration of >2000 healthy, young adults (aged 18-28 y) from the Trinity Student Study. Genotyping data were used to test association of plasma MI with single nucleotide polymorphisms (SNPs) in candidate genes, encoding inositol transporters and synthesizing enzymes, and test for genome-wide association. We evaluated potential correlation of plasma MI with d-chiro-inositol (DCI), glucose, and other metabolites by Spearman rank correlation.

RESULTS

Mean plasma MI showed a small but significant difference between males and females (28.5 and 26.9 μM, respectively). Candidate gene analysis revealed several nominally significant associations with plasma MI, most notably for SLC5A11 (solute carrier family 5 member 11), encoding a sodium-coupled inositol transporter, also known as SMIT2 (sodium-dependent myo-inositol transporter 2). However, these did not survive correction for multiple testing. Subsequent testing for genome-wide association with plasma MI did not identify associations of genome-wide significance (P < 5 × 10^-8). However, 8 SNPs exceeded the threshold for suggestive significant association with plasma MI concentration (P < 1 × 10^-5), 3 of which were located within or close to genes: MTDH (metadherin), LAPTM4B (lysosomal protein transmembrane 4 β), and ZP2 (zona pellucida 2). We found significant positive correlation of plasma MI concentration with concentration of dci and several other biochemicals including glucose, methionine, betaine, sarcosine, and tryptophan.

CONCLUSIONS

Our findings suggest potential for modulation of plasma MI in young adults by variation in SLC5A11, which is worthy of further investigation.

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.