4-Hydroxyisoleucine from Fenugreek (Trigonella foenum-graecum): Effects on Insulin Resistance Associated with Obesity

Fenfuro®-mediated arrest in the formation of protein-methyl glyoxal adducts: a new dimension in the anti-hyperglycemic potential of a novel fenugreek seed extract

The fenugreek plant (Trigonella foenum-graecum) is traditionally known for its anti-diabetic properties owing to its high content of furostanolic saponins, which can synergistically treat many human ailments. Non-enzymatic protein glycation leading to the formation of Advanced Glycation End products (AGE) is a common pathophysiology observed in diabetic or prediabetic individuals, which can initiate the development of neurodegenerative disorders. A potent cellular source of glycation is Methyl Glyoxal, a highly reactive dicarbonyl formed as a glycolytic byproduct. We demonstrate the in vitro glycation arresting potential of Fenfuro®, a novel patented formulation of Fenugreek seed extract with clinically proven anti-diabetic properties, in Methyl-Glyoxal (MGO) adducts of three abundant amyloidogenic cellular proteins, alpha-synuclein, Serum albumin, and Lysozyme. A 0.25% w/v Fenfuro® was able to effectively arrest glycation by more than 50% in all three proteins, as evidenced by AGE fluorescence. Glycation-induced amyloid formation was also arrested by more than 36%, 14% and 15% for BSA, Alpha-synuclein and Lysozyme respectively. An increase in MW by attachment of MGO was also partially prevented by Fenfuro® as confirmed by SDS-PAGE analysis. Glycation resulted in enhanced aggregation of the three proteins as revealed by Native PAGE and Dynamic Light Scattering. However, in the presence of Fenfuro®, aggregation was arrested substantially, and the normal size distribution was restored. The results cumulatively indicated the lesser explored potential of direct inhibition of glycation by fenugreek seed in addition to its proven role in alleviating insulin resistance. Fenfuro® boosts its therapeutic potential as an effective phytotherapeutic to arrest Type 2 diabetes.

Diabetes and diabesity in the view of proteomics, drug, and plant-derived remedies

Diabetes and obesity are highly prevalent in the world. Proteomics is a promising approach to better understanding enzymes, proteins, and signaling molecules involved in diabetes processes which help recognize the basis of the disease better and find suitable new treatments. This study aimed to summarize the molecular mechanisms from the beginning of insulin secretion in response to stimuli to the pathology of the insulin signaling pathway and, finally, the mechanisms of drugs/chemicals remedies that affect this process. The titles and subtitles of this process were determined, and then for each of them, the articles searched in PubMed and ScienceDirect were used. This review article starts the discussion with the molecular basis of insulin biosynthesis, secretion, insulin's mechanism of action, and molecular aspect of diabetes and diabesity (a new term showing the relation between diabetes and obesity) and ends with the drug and plant-derived intervention for hyperglycemia.

Simultaneous pharmacokinetic assessment of phytopharmaceuticals in fenugreek extract using LC-MS/MS in Sprague-Dawley rats

Fenugreek seeds are used in numerous marketed herbal formulations with therapeutic benefits. Some of its bioactive components such as 4-hydroxyisoleucine, trigonelline, raffinose, and pinitol are reported to possess potential therapeutic activities, such as antibacterial, antidiabetic, stomach stimulant, and anti-invasive, against hyperandrogenism and other allied diseases, including polycystic ovary syndrome. A fully validated, selective, and sensitive bioanalytical method for the simultaneous rapid quantification of the aforementioned bioactive components has been developed using hyphenated liquid chromatography electrospray tandem mass spectrometry. The analytes were separated within 5 min using gradient elution in a C18 column at a flow rate of 0.5 ml/min. Plasma protein precipitation technique was employed to isolate the analytes from the samples. Oral pharmacokinetic profile of the four bioactive components in Sprague-Dawley rats was further evaluated using noncompartmental analysis using Phoenix WinNonlin software.

Quality-controlled LC-ESI-MS food metabolomics of fenugreek (Trigonella foenum-graecum) sprouts: Insights into changes in primary and specialized metabolites

Fenugreek (Trigonella foenum-graecum L.) is an important food and spice with bioactive compounds against diabetes. In this study, fenugreek seeds germinating in darkness for 72 h were studied using quantification of trigonelline and 4-hydroxyisoleucine and an LC-ESI-MS/MS-based metabolomic approach capable of accurately estimating 237 features from various primary and specialized compound classes. During germination, the concentrations of trigonelline and 4-hydroxyisoleucine rose by 33.5% and 33.3%, respectively. At the same time, untargeted metabolomics revealed 9 putative flavonoids increasing 1.19- to 2.77-fold compared to the dormant seeds. A set of 19 steroid saponins rose by 1.08- to 31.86-fold. Primary metabolites however showed much more variability: abundance changes in amino acid derivatives, peptides and saccharides fell in the 0.09- to 22.25-fold, 0.93- to 478.79-fold and 0.36- to 941.58-fold ranges, respectively. To increase biosynthesis of specialized metabolites during germination, sprouts were exposed to 1-100 mM methyl jasmonate (MeJA) and methyl salicylate (MeSA). The hormone treatments affected normal metabolism: 67.1-83.1 % and 64.1-83.5 % of compounds showed a reduction compared to the controls in 100 mM MeJA and MeSA treatments at different sampling time points. Contrary to expectations, the abundance of flavonoids decreased, compared to the control sprouts (0.75- and 0.68-fold change medians, respectively). The same was observed for most, but not all steroid saponins. The quality-controlled untargeted metabolomics approach proved to yield excellent insight into the metabolic changes during germination of fenugreek. The results suggest that although fenugreek germination causes major shifts in plant metabolism, there are no major qualitative changes in bioactive specialized metabolites during the first three days. This stability likely translates into good bioactivity that is similar to that of the seeds. Because the large changes in the primary metabolites likely alter the nutritive value of the seed, further studies are warranted.

Computational pharmacology and computational chemistry of 4-hydroxyisoleucine: Physicochemical, pharmacokinetic, and DFT-based approaches

Computational pharmacology and chemistry of drug-like properties along with pharmacokinetic studies have made it more amenable to decide or predict a potential drug candidate. 4-Hydroxyisoleucine is a pharmacologically active natural product with prominent antidiabetic properties. In this study, ADMETLab 2.0 was used to determine its important drug-related properties. 4-Hydroxyisoleucine is compliant with important drug-like physicochemical properties and pharma giants' drug-ability rules like Lipinski's, Pfizer, and GlaxoSmithKline (GSK) rules. Pharmacokinetically, it has been predicted to have satisfactory cell permeability. Blood-brain barrier permeation may add central nervous system (CNS) effects, while a very slight probability of being CYP2C9 substrate exists. None of the well-known toxicities were predicted in silico, being congruent with wet lab results, except for a "very slight risk" for respiratory toxicity predicted. The molecule is non ecotoxic as analyzed with common indicators such as bioconcentration and LC₅₀ for fathead minnow and daphnia magna. The toxicity parameters identified 4-hydroxyisoleucine as non-toxic to androgen receptors, PPAR-γ, mitochondrial membrane receptor, heat shock element, and p53. However, out of seven parameters, not even a single toxicophore was found. The density functional theory (DFT) study provided support to the findings obtained from drug-like property predictions. Hence, it is a very logical approach to proceed further with a detailed pharmacokinetics and drug development process for 4-hydroxyisoleucine.

4-hydroxyisoleucine mediated IGF-1/GLP-1 signalling activation prevents propionic acid-induced autism-like behavioural phenotypes and neurochemical defects in experimental rats

Autism is a neuropsychiatric disorder characterized by a neurotransmitter imbalance that impairs neurodevelopment processes. Autism development is marked by communication difficulties, poor socio-emotional health, and cognitive impairment. Insulin-like growth factor-1 (IGF-1) and glucagon-like growth factor-1 (GLP-1) are responsible for regular neuronal growth and homeostasis. Autism progression has been linked to dysregulation of IGF-1/GLP-1 signalling. 4-hydroxyisoleucine (HI), a pharmacologically active amino acid produced from Trigonella foenum graecum, works as an insulin mimic and has neuroprotective properties. The GLP-1 analogue liraglutide (LRG) was employed in our investigation to compare the efficacy of 4-HI in autism prevention. The current study explores the protective effects of 4-HI 50 and 100 mg/kg orally on IGF-1/GLP-1 signalling activation in a PPA-induced experimental model of autism. Propionic acid (PPA) injections to rats by intracerebroventricular (ICV) route for the first 11 days of the experiment resulted in autism-like neurobehavioral, neurochemical, gross morphological, and histopathological abnormalities. In addition, we investigated the dose-dependent neuroprotective effects of 4-HI on the levels of several neurotransmitters and neuroinflammatory cytokines in rat brain homogenate and blood plasma. Neuronal apoptotic and anti-oxidant cellular markers were also studied in blood plasma and brain homogenate samples. Furthermore, the luxol fast blue (LFB) staining results demonstrated significant demyelination in the brains of PPA-induced rats reversed by 4-HI treatment. Rats were assessed for spontaneous locomotor impairments, neuromuscular coordination, stress-like behaviour, learning, and memory to assess neurobehavioral abnormalities. The administration of 4-HI and LRG significantly reversed the behavioural, gross and histological abnormalities in the PPA-treated rat brains. After treatment with 4-HI and LRG, LFB-stained photomicrographs of PPA-treated rats' brains demonstrated the recovery of white matter loss. Our findings indicate that 4-HI protects neurons in rats with autism by enhancing the IGF-1 and GLP-1 protein levels.

The role of selected nutraceuticals in management of prediabetes and diabetes: An updated review of the literature

Dysglycemia is a disease state preceding the onset of diabetes and includes impaired fasting glycemia and impaired glucose tolerance. This review aimed to collect and analyze the literature reporting the results of clinical trials evaluating the effects of selected nutraceuticals on glycemia in humans. The results of the analyzed trials, generally, showed the positive effects of the nutraceuticals studied alone or in association with other supplements on fasting plasma glucose and post-prandial plasma glucose as primary outcomes, and their efficacy in improving insulin resistance as a secondary outcome. Some evidences, obtained from clinical trials, suggest a role for some nutraceuticals, and in particular Berberis, Banaba, Curcumin, and Guar gum, in the management of prediabetes and diabetes. However, contradictory results were found on the hypoglycemic effects of Morus, Ilex paraguariensis, Omega-3, Allium cepa, and Trigonella faenum graecum, whereby rigorous long-term clinical trials are needed to confirm these data. More studies are also needed for Eugenia jambolana, as well as for Ascophyllum nodosum and Fucus vesiculosus which glucose-lowering effects were observed when administered in combination, but not alone. Further trials are also needed for quercetin.

4-Hydroxyisoleucine inhibits tumor growth by triggering endoplasmic reticulum stress and autophagy

4-Hydroxyisoleucine（4-HIL）is a non-protein amino acid that is able to reduce obesity and improve insulin sensitivity in mice, and recently emerged as a drug candidate against hypoglycemia. For the first time, we found that 4-HIL exhibits a potent anti-tumor activity in various cancer cell lines in vitro and in vivo. Most importantly, 4-HIL has no cytotoxic effect on normal or non-malignant cells. Proteomic data analysis revealed changes in endoplasmic reticulum stress（ERS）related protein and autophagy related protein. Western blot revealed that molecular components of the ERS pathway were activated, including phosphorylation of perk and EIF2a increased, while levels of GRP78 reduced, the cellular process of ERS potentially contributed to the activation of autophagy, Transmission electron microscopy revealed the formation of autophagic vesicles under 4-HIL treatment, and LC3B was increased. Meanwhile, activation of ERS inhibits intracellular protein synthesis rate, our results suggest that 4-HIL exhibits anti-tumor activity in various cancer cell lines by increasing ERS and triggering autophagy responses without causing damage to normal cells.

Exploring the medicinally important secondary metabolites landscape through the lens of transcriptome data in fenugreek (Trigonella foenum graecum L.)

Fenugreek (Trigonella foenum-graecum L.) is a self-pollinated leguminous crop belonging to the Fabaceae family. It is a multipurpose crop used as herb, spice, vegetable and forage. It is a traditional medicinal plant in India attributed with several nutritional and medicinal properties including antidiabetic and anticancer. We have performed a combined transcriptome assembly from RNA sequencing data derived from leaf, stem and root tissues. Around 209,831 transcripts were deciphered from the assembly of 92% completeness and an N50 of 1382 bases. Whilst secondary metabolites of medicinal value, such as trigonelline, diosgenin, 4-hydroxyisoleucine and quercetin, are distributed in several tissues, we report transcripts that bear sequence signatures of enzymes involved in the biosynthesis of such metabolites and are highly expressed in leaves, stem and roots. One of the antidiabetic alkaloid, trigonelline and its biosynthesising enzyme, is highly abundant in leaves. These findings are of value to nutritional and the pharmaceutical industry.

Activation of IGF-1/GLP-1 Signalling via 4-Hydroxyisoleucine Prevents Motor Neuron Impairments in Experimental ALS-Rats Exposed to Methylmercury-Induced Neurotoxicity

Amyotrophic lateral sclerosis (ALS) is a severe adult motor neuron disease that causes progressive neuromuscular atrophy, muscle wasting, weakness, and depressive-like symptoms. Our previous research suggests that mercury levels are directly associated with ALS progression. MeHg+-induced ALS is characterised by oligodendrocyte destruction, myelin basic protein (MBP) depletion, and white matter degeneration, leading to demyelination and motor neuron death. The selection of MeHg+ as a potential neurotoxicant is based on our evidence that it has been connected to the development of ALS-like characteristics. It causes glutamate-mediated excitotoxicity, calcium-dependent neurotoxicity, and an ALS-like phenotype. Dysregulation of IGF-1/GLP-1 signalling has been associated with ALS progression. The bioactive amino acid 4-hydroxyisoleucine (HI) from Trigonella foenum graecum acts as an insulin mimic in rodents and increases insulin sensitivity. This study examined the neuroprotective effects of 4-HI on MeHg+-treated adult Wistar rats with ALS-like symptoms, emphasising brain IGF1/GLP-1 activation. Furthermore, we investigated the effect of 4-HI on MBP levels in rat brain homogenate, cerebrospinal fluid (CSF), blood plasma, and cell death indicators such as caspase-3, Bax, and Bcl-2. Rats were assessed for muscular strength, locomotor deficits, depressed behaviour, and spatial learning in the Morris water maze (MWM) to measure neurobehavioral abnormalities. Doses of 4-HI were given orally for 42 days in the MeHg+ rat model at 50 mg/kg or 100 mg/kg to ameliorate ALS-like neurological dysfunctions. Additionally, neurotransmitters and oxidative stress markers were examined in rat brain homogenates. Our findings suggest that 4-HI has neuroprotective benefits in reducing MeHg+-induced behavioural, neurochemical, and histopathological abnormalities in ALS-like rats exposed to methylmercury.

Association between SNPs in Leptin Pathway Genes and Anthropometric, Biochemical, and Dietary Markers Related to Obesity

Obesity is one of the main public health problems in Mexico and the world and one from which a large number of pathologies derive. Single nucleotide polymorphisms (SNPs) of various genes have been studied and proven to contribute to the development of multiple diseases. SNPs of the leptin pathway have been associated with the control of hunger and energy expenditure as well as with obesity and type 2 diabetes mellitus. Therefore, the present work focused on determining the association between anthropometric markers and biochemical and dietary factors related to obesity and SNPs of leptin pathway genes, such as the leptin gene (LEP), the leptin receptor (LEPR), proopiomelanocortin (POMC), prohormone convertase 1 (PCSK1), and the melanocortin 4 receptor (MC4R). A population of 574 young Mexican adults of both sexes, aged 19 years old on average and without metabolic disorders previously diagnosed, underwent a complete medical and nutritional evaluation, biochemical determination, and DNA extraction from the blood; DNA samples were subsequently genotyped. Association analyses between anthropometric, biochemical, and dietary variables with SNPs were performed using binary logistic regressions (p-value = 0.05). Although the sampled population did not have previously diagnosed diseases, the evaluation results showed that 33% were overweight or obese according to BMI and 64% had non-clinically elevated levels of body fat. From the 74 SNP markers analyzed from the five previously mentioned genes, 62 showed polymorphisms within the sampled population, and only 35 of these had significant associations with clinical variables. The risk associations (OR > 1) occurred between clinical markers with elevated values for waist circumference, waist−height index, BMI, body fat percentage, glucose levels, insulin levels, HOMA-IR, triglyceride levels, cholesterol levels, LDL-c, low HDL-c, carbohydrate intake, and protein intake and SNPs of the LEP, LEPR, PCSK1, and MC4R genes. On the other hand, the protective associations (OR < 1) were associated with markers including elevated values for insulin, HOMA-IR, cholesterol, c-LDL, energy intake > 2440 Kcal/day, and lipid intake and SNPs of the LEP and LEPR genes and POMC. The present study describes associations between SNPs in leptin pathway genes, revealing positive and negative interactions between reported SNPs and the clinical markers related to obesity in a sampled Mexican population. Hence, our results open the door for the further study of new genetic variants and their influence on obesity.

Formulation, Characterization and Permeability Studies of Fenugreek (Trigonella foenum-graecum) Containing Self-Emulsifying Drug Delivery System (SEDDS)

Fenugreek is used as a spice and a traditional herbal medicine for a variety of purposes, given its antidiabetic and antioxidant effects. Self-emulsifying drug delivery systems (SEDDS) of herbal drugs are targets of extensive research aiming to increase bioavailability and stability. The study’s objective was to formulate SEDDS containing Trigonella foenum-graecum extract to improve the stability of herbal extract and to increase their permeability through a Caco-2 monolayer. A characterized fenugreek dry extract was used for the formulations, while the SEDDS properties were examined by particle size analysis and zeta potential measurements. Permeability assays were carried out on Caco-2 cell monolayers, the integrity of which was monitored by follow-up trans-epithelial electric resistance measurements (TEER). Cytocompatibility was tested by the MTT method, and an indirect dissolution test was performed, using DPPH antioxidant reagent. Two different SEDDS compositions were formulated from a standardized fenugreek dry extract at either the micro- or the nanoemulsion scale with sufficient stability, enhanced bioavailability of the compounds, and sustained release from HPMC capsules. Based on our results, a modern, non-toxic, cytocompatible fenugreek SEDDS formulation with high antioxidant capacity was developed in order to improve the permeability and bioavailability of all components.

Characterization of Possible α-Glucosidase Inhibitors from Trigonella stellata Extract Using LC-MS and In Silico Molecular Docking

The current study accentuates the significance of performing the multiplex approach of LC-HRESIMS, biological activity, and docking studies in drug discovery, taking into consideration a review of the literature. In this regard, the investigation of antioxidant and cytotoxic activities of Trigonella stellata collected from the Egyptian desert revealed a significant antioxidant capacity using DPPH with IC₅₀ = 656.9 µg/mL and a moderate cytotoxicity against HepG2, MCF7, and CACO2, with IC₅₀ values of 53.3, 48.3, and 55.8 µg/mL, respectively. The evaluation of total phenolic and flavonoid contents resulted in 32.8 mg GAE/g calculated as gallic acid equivalent and 5.6 mg RE/g calculated as rutin equivalent, respectively. Chemical profiling of T. stellata extract, using LC-HRESIMS analysis, revealed the presence of 15 metabolites, among which eleven compounds were detected for the first time in this species. Interestingly, in vitro testing of the antidiabetic activity of the alcoholic extract noted an α-glucosidase enzyme inhibitory activity (IC₅₀ = 559.4 µg/mL) better than that of the standard Acarbose (IC₅₀ = 799.9 µg/mL), in addition to a moderate inhibition of the α-amylase enzyme (IC₅₀ = 0.77 µg/mL) compared to Acarbose (IC₅₀ = 0.21 µg/mL). α-Glucosidase inhibition was also virtualized by binding interactions through the molecular docking study, presenting a high binding activity of six flavonoid glycosides, as well as the diterpenoid compound graecumoside A and the alkaloid fenugreekine. Taken together, the conglomeration of LC-HRESIMS, antidiabetic activity, and molecular docking studies shed light on T. stellata as a promising antidiabetic herb.

Neuroprotective efficacy of 4-Hydroxyisoleucine in experimentally induced intracerebral hemorrhage

Intracerebral hemorrhage (ICH) is a severe form of brain injury, which is a major cause of mortality in humans. Hydrocephalus and cerebral hematoma lead to severe neurological deficits. A single autologous blood (ALB) injection in rats' brains induces hemorrhage and other conditions that regularly interfere with the standard treatment of several cellular and molecular pathways. Several studies have found that IGF-1/GLP-1 decreases the production of inflammatory markers in peripheral tissues, while some have found that they also have pro-inflammatory functions. Since these receptors are down-regulated in hemorrhagic situations, we looked into the potential neuroprotective effect of 4-hydroxyisoleucine (4-HI); 50 mg/kg and 100 mg/kg, an active compound Trigonellafoenum-graecum, on post-hemorrhagic deficits in rats. Long-term oral administration of 4-HI for 35 days has improved behavioral and neurochemical deficits and severe pathological changes and improved cellular and molecular markers, apoptotic markers in the ALB-induced ICH experimental model.

Furthermore, the findings revealed that 4-HI also improved the levels of other neurotransmitters (Ach, DOPA, GABA, glutamate); inflammatory cytokines (TNF-alpha, IL-1β, IL-17), and oxidative stress markers (MDA, nitrite, LDH, AchE, SOD, CAT, GPx, GSH) in the brain when evaluated after Day 35. There is no proven treatment available for the prevention of post-brain hemorrhage and neurochemical malfunction; available therapy is only for symptomatic relief of the patient. Thus, 4-HI could be a potential clinical approach for treating post-brain haemorrhage and neurochemical changes caused by neurological damage. Furthermore, 4-HI may be linked to other standard therapeutic therapies utilized in ICH as a potential pharmacological intervention.

Omega-3 Rich Oils Attenuate ADHD-Like Behaviour Induced by Dietary Monosodium Glutamate in Rats

&lt;b&gt;Background and Objective:&lt;/b&gt; Attention Deficit Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder characterized by inattention, hyperactivity and cognitive dysfunction. The present study was designed to examine the possible modulatory effect of Fish, Walnuts or Fenugreek Oils against Attention Deficit Hyperactivity Disorder (ADHD)-like Behavior induced by Monosodium Glutamate (MSG) in Rats. &lt;b&gt;Materials and Methods:&lt;/b&gt; Fifty weaning rats were divided into five groups, (each group contain 10 rats) as follows: Group 1: Normal control rats were fed on a balanced diet. Groups from 2-5 rats were fed on a balanced diet+MSG (0.4 g kg&lt;sup&gt;&lt;/sup&gt;&lt;sup&gt;1&lt;/sup&gt; diet), Group 2 served as a positive control group whereas group 3, 4 and 5 treated with Fish, Walnuts and Fenugreek oil, respectively, (200 mg kg&lt;sup&gt;&lt;/sup&gt;&lt;sup&gt;1&lt;/sup&gt; b.wt.) by intra-gastric tube. Biochemical and behavioural parameters were tested as well as microscopic examination of brain tissue was done. &lt;b&gt;Results:&lt;/b&gt; MSG ingestion caused marked disruption in locomotors activity, memory function and brain tissue structure along with significant abnormalities in some bio-markers and reduction in the gene expression level of Bcl-2 in brain tissue. However, treatment with the tested oils showed remarkable effect by reversing the condition. &lt;b&gt;Conclusion:&lt;/b&gt; Dietary supplementation with walnut; fenugreek or fish oils at the tested dose could modulate the condition of ADHD in rats.

The Possible Role of Saponin in Type-II Diabetes- A Review

BACKGROUND

The possible role of secondary metabolites in the management of diabetes is a great concern and constant discussion. This characteristic seems relevant and should be the subject of thorough discussion with respect to saponin.

OBJECTIVE

The current data mainly focus on the impact of saponin in the treatment of type-II diabetes. The majority of studies emphasize on other secondary metabolites such as alkaloids and flavonoids, but very few papers are there representing the possible role of saponin as these papers express the narrow perspective of saponin phytoconstituents but lacking in providing the complete information on various saponin plants. The aim of the study was to summarize all available data concerning the saponin containing plant in the management of type-II diabetes.

METHODS

All relevant papers on saponin were selected. This review summarizes the saponin isolation method, mechanism of action, clinical significance, medicinal plants and phytoconstituents responsible for producing a therapeutic effect in the management of diabetes.

RESULTS

The saponin is of high potential with structural diversity and inhibits diabetic complications along with reducing the hyperglycemia through different mechanisms thereby providing scope for improving the existing therapy and developing the novel medicinal agents for curing diabetes.

CONCLUSION

Saponins having potential therapeutic benefits and are theorized as an alternative medication in decreasing serum blood glucose levels in the patient suffering from diabetes.

4-Hydroxyisoleucine relieves inflammation through iRhom2-dependent pathway in co-cultured macrophages and adipocytes with LPS stimulation

Background

4-Hydroxyisoleucine (4-HIL) is an active ingredient extracted from Trigonella foenum-graecum L., a Chinese traditional herbal medicine, which exerts the efficacy of anti-obesity and anti-diabetes. We previously reported that 4-HIL potentiates anti-inflammatory and anti-insulin resistance effects through down-regulation of TNF-α and TNF-α converting enzyme (TACE) in 3 T3-L1 adipocytes and HepG2 cells. In the present study, we further investigate the effects and mechanisms of 4-HIL on obesity-induced inflammation in RAW264.7 macrophages and 3 T3-L1 adipocytes co-culture system.

Methods

RAW264.7 macrophages and 3 T3-L1 adipocytes were co-cultured to mimic the microenvironment of adipose tissue. siRNA-iRhom2 transfection was performed to knockdown iRhom2 expression in RAW264.2 macrophages. The mRNA and protein expression of iRhom2 and TACE were measured by real-time quantitative PCR (RT-qPCR) and western blotting. The production of tumor necrosis factor-α (TNF-α), monocyte chemotactic protein-1 (MCP-1), IL-6 and IL-10 were evaluated by ELISA. The ratio of M2/M1 was detected by flow cytometry.

Results

4-HIL significantly repressed the mRNA and protein levels of iRhom2 and TACE in RAW264.7 macrophages after LPS stimulated. Meanwhile, the levels of pro-inflammatory cytokines, including TNF-α, MCP-1, and IL-6, were substantially suppressed by 4-HIL in the co-culture system. Moreover, the level of anti-inflammatory cytokine IL-10 was increased significantly by 4-HIL in the co-culture system after LPS stimulation. Additionally, the ratio of M2/M1 was also increased by 4-HIL in the co-culture system after LPS stimulation. Finally, these effects of 4-HIL were largely enhanced by siRNA-iRhom2 transfection.

Conclusion

Taken together, our results indicated that obesity-induced inflammation was potently relieved by 4-HIL, most likely through the iRhom2-dependent pathway.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-020-03166-1.

Efficacy of a novel extract of fenugreek seeds in alleviating vasomotor symptoms and depression in perimenopausal women: A randomized, double-blinded, placebo-controlled study

The present randomized, double-blinded, placebo-controlled study investigated the effect of a standardized fenugreek extract (FHE) on perimenopausal discomforts and its influence on hormonal balance and safety. Healthy women characterized with perimenopausal symptoms (n = 48), as assessed by MRS questionnaire, were randomized either to FHE (n = 24) or placebo (n = 24) and supplemented with 250 mg × 2/day for 42 days. Both inter and intra-group comparison revealed a significant improvement in somatic, psychological, and urogenital scores in FHE group, especially for hot flashes (25.9%), night sweats (26.5%), depression (31.8%), and insomnia (21.6%). Further hormone analysis revealed an enhancement in serum estradiol (18.9%), free testosterone (38.2%), and progesterone (19.9%) concentrations and a significant decrease in FSH (38.2%) and SHBG (21.1%) concentrations toward establishing a hormonal balance among FHE-group; without significant changes in other clinical safety parameters. Thus, FHE supplementation offered a significant reduction in vasomotor effects and depression in perimenopausal women, without any adverse effects PRACTICAL APPLICATIONS: Fenugreek is a popular kitchen spice and Ayurvedic medicine for a variety of health conditions including diabetes, hypercholesterolemia, hepatotoxicity, gastritis, and also for a variety of hormone-related health conditions such as sexual functions, lactation, osteoporosis, PCOS, and post/perimenopausal discomforts. Fenugreek is rich in alkaloids, steroidal saponins, flavonoids and 4-hydroxyisoleucine. The present randomized-controlled study investigated the plausible application of a standardized hydro-ethanolic extract of fenugreek seeds (FHE) having a unique 3:1 ratio for protodioscin to trigonelline in the management of perimenopausal discomforts. It was observed that FHE at a dosage of 250 mg × 2/day for 42 days significantly reduced the discomforts, especially vasomotor symptoms and depression, and helped to attain a hormonal balance without any adverse effects or deviations in clinical safety parameters. Thus, FHE could be a potential natural agent for the management of post and perimenopausal discomforts and has to be explored in future studies.

In vitro studies on different extracts of fenugreek (Trigonella spruneriana BOISS.): Phytochemical profile, antioxidant activity, and enzyme inhibition potential

The side effects of synthetic antioxidants make it necessary to find a natural alternative. Therefore, the current study investigates the potential of T. spruneriana as a new alternative in terms of natural bioactive components. In this context, antioxidant activity, enzyme inhibition, and phenolic compounds of different extracts including ethanol, methanol, ethyl acetate, and aqueous were identified. The results show that the ethyl acetate (113.59 ± 2.73 mg GAE/g) has the highest phenolic content, but ethanol extract has the highest scavenging activity for DPPH and TAC. The ethanol extract showed stronger inhibition on cholinesterase and α-amylase compared to other extracts. Besides, 12 bioactive compounds were characterized in T. spruneriana extracts by HPLC-DAD. Our findings support that T. spruneriana could be considered as a new source of active phytochemicals, as well as provide remarkable data on biological activities of some main enzymes playing role in the healing of hyperpigmentation, Alzheimer, and diabetes. PRACTICAL APPLICATIONS: This study reports the total content, types and amounts of bioactive compounds and potential beneficial bioactivities of the different extracts of T. spruneriana. Trigonella is abundant in nature and spread over a wide geographical area, and is used in making cheese, pastries, spices, and sausages in different countries, as well as for antidiabetic purposes. Trigonella leaves are a good source of bioactive compounds that contain compounds like quercetin, catechin, cinnamic acid, and coumaric acid, along with it have also a high content of soluble fibers and is suggested for body weight control. Apart from being the first study conducted to point out the potential of T. spruneriana as being a natural food additive, this study also demonstrated its medicinal importance by revealing the anti-hyperpigmentation, antidiabetic, neuroprotective, and antioxidant properties of T. spruneriana.

Optimization of ribosomal binding site sequences for gene expression and 4-hydroxyisoleucine biosynthesis in recombinant corynebacterium glutamicum

4-Hydroxyisoleucine (4-HIL) has potential value for treating diabetes. α-Ketoglutarate (α-KG)-dependent l-isoleucine dioxygenase (IDO) can convert l-isoleucine (Ile) into 4-HIL. In our previous study, 4-HIL was de novo synthesized from glucose by expressing the ido gene in Corynebacterium glutamicum strain SN01, an Ile producer, and neither Ile nor α-KG was added. In this study, ribosomal binding site (RBS) engineering was applied for gene expression and 4-HIL biosynthesis in C. glutamicum. The 18 tested RBS sequences showed greatly differing strengths for expressing ido, and 8.10-104.22 mM 4-HIL was produced. To supply the cosubstrate α-KG at different levels, the odhI gene was then expressed using the RBS sequences of high, medium, and low strength in the above mentioned optimal strain SF01 carrying R8-ido. However, 4-HIL production decreased to varying amounts, and in some strains, the α-KG was redirected into l-glutamate synthesis. Next, the O₂ supply was further enhanced in three ido-odhI coexpressing strains by overexpressing the vgb gene, and 4-HIL production changed dramatically. 4-HIL (up to 119.27 ± 5.03 mM) was produced in the best strain, SF08, suggesting that the synchronic supply of cosubstrates α-KG and O₂ is critical for the high-yield production of 4-HIL. Finally, the avtA gene and the ldhA-pyk2 cluster were deleted separately in SF08 to reduce pyruvate-derived byproducts, and 4-HIL production increased to 122.16 ± 5.18 and 139.82 ± 1.56 mM, respectively, indicating that both strains were promising candidates for producing 4-HIL. Therefore, fine-tuning ido expression and the cosubstrates supply through RBS engineering is a useful strategy for improving 4-HIL biosynthesis in C. glutamicum.

Comparison of the efficacy of oral fenugreek seeds hydroalcoholic extract versus placebo in nonalcoholic fatty liver disease; a randomized, triple-blind controlled pilot clinical trial

OBJECTIVES

The aim of this study is to investigate the therapeutic property of hydroalcoholic extract of Fenugreek seeds in nonalcoholic fatty liver disease (NAFLD) in adult patients.

METHODS

This randomized, placebo-controlled, parallel trial was conducted from November 2014 to June 2017. Patients aged between 18 and 70 years old with confirmed NAFLD were recruited from the Motahhari clinic, affiliated to Shiraz University of Medical Sciences, Iran. Participants either received 1 g hydroalcoholic extract of Fenugreek seeds or placebo daily for 3 months. The primary outcomes were changes in serum alanine transaminase and FibroScan controlled attenuation parameter score. Secondary outcome measures were changes in other laboratory data, liver stiffness measure, liver steatosis percent, and anthropometric variables. Participants were randomly assigned to the groups using blocked randomization method. Participants, investigators, and statistician were blinded to treatments allocation.

RESULTS

After screening eighty patients, thirty patients met the inclusion criteria and were divided into two groups (1:1). After 3 months, two and four patients did not complete the trial in Fenugreek and placebo group, respectively. The changes in the anthropometrics, laboratories and FibroScan measurements were not statistically significant between the two groups.

CONCLUSION

The evidence to prove the efficacy of the Fenugreek seeds' hydroalcoholic extract in NAFLD was not strong enough; hence, further experiments are still needed to assess the possible efficacy of Fenugreek on the treatment of NAFLD.

Diosgenin and 4-Hydroxyisoleucine from Fenugreek Are Regulators of Genes Involved in Lipid Metabolism in The Human Colorectal Cancer Cell Line SW480

Objective

Diosignin and 4-hydroxy-L-isulosine (4-OH-Ile) are the two active ingredients of Fenugreek (Trigonella foenumgraecum). Thus, in this study, we examined the effects of hydroalcoholic extract of fenugreek seeds (HEFS), diosgenin and 4-OH-Ile on the expression of acetyl-CoA carboxylase (ACC), fatty acid synthase (FAS), peroxisome proliferator-activated receptor gamma (PPARγ) and low-density lipoprotein (LDL) receptor (LDLR) which are involved in lipid metabolism in SW480 cell line.

Materials and Methods

In this experimental study, SW480 cells were cultured in RPMI-1640 medium and treated with HEFS, diosignin, 4-OH-Ile or orlistat for 24 and 48 hours. Inhibitory concentration of 20% (IC20) was calculated using MTT method and cells were then pre-treated with the IC20 concentrations for 24 and 48 hours before RNA extraction and cDNA synthesis. Changes in the expression of ACC, FAS, PPARγ and LDLR genes were assayed by employing the real time-polymerase chain reaction (PCR) method.

Results

Our results showed a significant down-regulation in the expression of ACC (P<0.001 and P<0.001 after 24 and 48 hours, respectively) and FAS genes (P<0.001 and P<0.001 after 24 and 48 hours, respectively) in SW480 cells treated with HEFS, diosignin, 4-OH-Ile, or orlistat, but significant up-regulation in the expression of PPARγ (P<0.001 and P<0.001 after 24 and 48 hours, respectively) and LDLR (P=0.005 and P=0.001 after 24 and 48 hours, respectively).

Conclusion

According to the results of the present study, HEFS, diosgenin and 4-OH-Ile up or down-regulate the expression of some predominant genes involved in lipid metabolism pathway, similar to that observed for orlistat. These types of regulatory effects are presumably proper for the treatment of obesity and overweight.

Pre-clinical pharmacokinetic and pharmacodynamic modelling study of 4-hydroxyisoleucine using validated ultra-performance liquid chromatography-tandem mass spectrometry

A reliable and sensitive ultra-performance liquid chromatography-tandem mass spectrometry-based method has been developed for the estimation of 4-hydroxyisoleucine (4-HI), a potent insulinotropic and hypolipidemic agent. The extraction of 4-HI from plasma was accomplished by the protein precipitation technique using l-isoleucine as an internal standard. The separation of analytes was achieved with a mobile phase consisting of acetonitrile and 0.1% formic acid in an isocratic flow system on a BEH Shield RP-18 column (150 mm × 2.1 mm, 1.7 μm). 4-HI and l-isoleucine were detected using an electrospray ionization (ESI) ion source, using multiple reaction monitoring (MRM) in positive ion mode. The precursor to product ion transitions of 4-HI and l-isoleucine were found at m/z values of 148.19 > 74.02 and 132.17 > 69.04, respectively. As per the guidelines for bioanalytical methods, all validation parameter results were within the acceptable range. The method exhibited a robust and reproducible linearity range of 1–5000 ng mL⁻¹ with a coefficient of regression of 0.9999. The method was successfully applied for the estimation of pharmacokinetic parameters after oral administration of 4-HI (10 mg kg⁻¹) in Wistar rats, by using Thoth Pro (version: 4.3) software. Herein, the two-compartment model was statistically fitted based on AIC and SBC values for evaluation of the pharmacokinetic parameters of 4-HI. Pharmacodynamic studies were also performed by measuring the levels of triglyceride and total cholesterol, and showed that the pharmacokinetic and pharmacodynamic data of 4-HI correlated with each other.

A reliable and sensitive UPLC-MS/MS based method has been developed for the estimation of 4-hydroxyisoleucine, a potent insulinotropic and hypolipidemic agent.

Determination of Bioactive Compounds of Fenugreek (Trigonella foenum-graecum) Seeds Using LC-MS Techniques

Trigonella foenum-graecum (fenugreek), a legume has been used as spice throughout the world to enhance the sensory quality of foods, is considered to have a high nutraceutical value. The antidiabetic actions of Trigonella seeds have been speculated due to the presence of steroid saponins, alkaloids, and fiber content. Five bioactive compounds, namely, trigonelline, isoorientin, orientin, vitexin, and isovitexin, were detected and quantified by HPLC system. Further rapid detection of bioactive compounds was achieved using high-performance liquid chromatography hybrid electrospray quadrupole time-of-flight mass spectrometric (HPLC-ESI-QTOF-MS/MS) method. Twenty-five compounds were tentatively identified based on their retention time and measured accurate mass. The fragmentation patterns of known compounds were utilized to elucidate their structures. Six of these identified compounds, that is, 4-hydroxyisoleucine, trigonelline, isoorientin, isovitexin, pinitol, and sarsasapogenin, were simultaneously quantified by UHPLC-ESI-MS/MS method under the multiple reactions monitoring (MRM) mode using ultrahigh-performance liquid chromatography hybrid electrospray triple quadrupole linear ion trap mass spectrometer. The analytical method was validated and successfully applied for simultaneous determination of compounds in Fenugreek seeds, which indicated the suitability of the validated method for its quality control.

Spice-Derived Bioactive Ingredients: Potential Agents or Food Adjuvant in the Management of Diabetes Mellitus

Spices possess tremendous therapeutic potential including hypoglycemic action, attributed to their bioactive ingredients. However, there is no study that critically reviewed the hypoglycemic potency, safety and the bioavailability of the spice-derived bioactive ingredients (SDBI). Therefore, the aim of the study was to comprehensively review all published studies regarding the hypoglycemic action of SDBI with the purpose to assess whether the ingredients are potential hypoglycemic agents or adjuvant. Factors considered were concentration/dosages used, the extent of blood glucose reduction, the IC50 values, and the safety concern of the SDBI. From the results, cinnamaldehyde, curcumin, diosgenin, thymoquinone (TQ), and trigonelline were showed the most promising effects and hold future potential as hypoglycemic agents. Conclusively, future studies should focus on improving the tissue and cellular bioavailability of the promising SDBI to achieve greater potency. Additionally, clinical trials and toxicity studies are with these SDBI are warranted.

Sufficient NADPH supply and pknG deletion improve 4-hydroxyisoleucine production in recombinant Corynebacterium glutamicum

Cofactor engineering is a common strategy to improve amino acid production. 4-hydroxyisoleucine (4-HIL), a nonproteinogenic amino acid, exhibits unique insulinotropic and insulin-sensitizing activities, therefore has potential medical value in treating diabetes. In our previous study, l-isoleucine (Ile) dioxygenase gene ido was overexpressed in an Ile-producing Corynebacterium glutamicum strain, and 4-HIL was de novo synthesized from glucose. In this study, to increase the NADPH supply, the endogenous NAD⁺ kinase gene ppnK and glucose-6-phosphate dehydrogenase gene zwf were co-expressed with ido. The resulting strain SL01 produced 81.12 ± 5.96 mM 4-HIL, 62% higher than the ido-mere expressing strain SN02. However, the strain SL02 co-expressing exogenous NADH kinase gene POS5 with ido grew slowly and its 4-HIL production decreased by 12%, perhaps due to the lower 2-oxoglutarate (OG) level and slightly weaker membrane permeability. To increase OG availability for 4-HIL conversion, the serine/threonine protein kinase G gene pknG was deleted and replaced by ido gene in SL02. The growth of the resulting strain SL04 was restored and 4-HIL production was improved to 84.14 ± 6.38 mM; meanwhile, the conversion ratio of Ile to 4-HIL reached up to 0.98 ± 0.01 mol/mol. Therefore, sufficient NADPH supply and OG availability may be benefit to 4-HIL de novo biosynthesis in recombinant C. glutamicum.

Irisin a Novel Metabolic Biomarker: Present Knowledge and Future Directions

The rising prevalence of chronic diseases such as type 2 diabetes and cardiovascular diseases owing to fat mass excess has been described. In recent years, muscle function/dysfunction has become relevant in metabolic homeostasis. Irisin was described as an exercise-induced myokine. It is the product of type I membrane protein cleavage encoded by the fibronectin type III domain containing 5 (FNDC5) gene. The main beneficial function attributable to irisin is the change of subcutaneous and visceral adipose tissue into brown adipose tissue, with a consequential increase in thermogenesis. Irisin has also been described as a hormone that may have a key role in glucose homeostasis. The way the association of type 2 diabetes with obesity occurs is not fully understood. In recent years, the possible pathways through which irisin could interact with other organs such as the brain or bone have been described. The present paper intends to review the new findings and possible new directions in irisin research.