The Effects of Monosodium Glutamate and Tannic Acid on Adult Rats

The Role of Vitamin C on ATPases Activities in Monosodium Glutamate-Induced Oxidative Stress in Rat Striatum and Cerebellum

Monosodium glutamate (MSG) is a silent excitotoxin used as a flavour enhancer but exerts serious health hazards to consumers. MSG plays a role in neuronal function as the dominant excitatory neurotransmitter. It is transferred into the blood and ultimately increases brain glutamate levels, causing functional disruptions notably via oxidative stress. The study evaluated the toxic effect of high consumption of MSG and the modulatory role of vitamin C on ATPase activities in the striatum and cerebellum of male Wistar rats for five weeks. Rats were grouped into four (A-D): group A was fed with rat's show only; Group B was fed with diet containing 15% MSG; Group C was treated with vitamin C (200 mg/kg b.wgt orally in 0.9% saline solution) only for 3 weeks; and group D rats were fed with MSG and vitamin C. The findings show that MSG does not affect body and cerebellum weights but increases striatal weight. MSG increases the malondialdehyde (MDA) level and significantly decreases catalase (CAT) and superoxide dismutase (SOD) activities and glutathione (GSH) levels. MSG significantly impaired striatal and cerebellar ATPases activities (Na+/K+-, Ca2+-, Mg2+- and total ATPases). Vitamin C treatment abolishes MSG-induced oxidative stress and improves ATPase activities. The findings show that vitamin C has beneficial effects in improving the functions of membrane-bound ATPases against MSG toxicity in rat's striatum and cerebellum.

Hematological changes, oxidative stress assessment, and dysregulation of aquaporin-3 channel, prolactin, and oxytocin receptors in kidneys of lactating Wistar rats treated with monosodium glutamate

High consumption of locally produced delicacies could expose nursing mothers to high monosodium glutamate (MSG) levels, frequently used as a necessary condiment in low-income countries. Thus, this study evaluated some novel preliminary changes in renal hormonal receptors, the aquaporin-3 channel, oxidative stress markers, and hematological indices induced by monosodium glutamate in lactating rats. Post-parturition, twenty-four (24) lactating Wistar rats were divided into four (4) groups of six rats each (n = 6). Oral administration of distilled water and MSG started three (3) days postpartum as follows: group 1: distilled water (1 ml/kg BW), group 2: MSG (925 mg/kg BW), group 3: MSG (1850 mg/kg BW), and group 4: MSG (3700 mg/kg BW). At the end of the experiment, which lasted fourteen (14) days, animals were sacrificed and samples of blood and tissues were obtained for biochemical analysis. MSG administration significantly (p < 0.05) increased ROS and MDA, with a significant (p < 0.05) decrease in kidney antioxidants. Serum creatinine, total, conjugated, and unconjugated bilirubin significantly (p < 0.05) increased with MSG administration. The prolactin receptor was significantly reduced (p < 0.05), while the oxytocin receptor and aquaporin-3 channel were significantly (p < 0.05) increased in the MSG-administered groups. There were significant (p < 0.05) changes in the hematological indices of the MSG-administered animals. Thus, the findings of this study suggest that high MSG consumption causes hematological alterations and may alter renal function via increased ROS production and dysregulation of the AQP-3 channel, prolactin, and oxytocin receptors in the kidneys of lactating Wistar rats.

Neuroprotective activity of Colocasia esculenta (L.) Schott leaves against monosodium glutamate-induced excitotoxicity in rats: phytochemical and molecular docking study

Colocasia esculenta (L.) Schott is a food crop with long history of use in treatment of various disorders including neurological diseases. The methanolic leaves extract (ME) and its n-butanol fraction (n-BF) demonstrated significant in vivo neuroprotective activity in monosodium glutamate induced excitotoxicity in rats. Sixteen and fifteen polyphenolic compounds were identified in n-BF and ME, respectively, using HPLC. Phytochemical investigation of n-BF followed by 1D (1H and 13C NMR) spectroscopic analyses led to isolation and identification of daucosterol (1), thermopsoside (2) and chrysoeriol 7-O-β-D-neohesperidoside (3) for the first time from genus Colocasia, in addition to orientin (4). LC/MS/MRM analysis of fraction V obtained from n-BF revealed identification of 13 polyphenolic compounds. Molecular docking of isolated compounds confirmed binding of all compounds at the target pocket with higher energy than crystallised ligand. The current study evaluated and confirmed the mechanistic aspects of neuroprotective activity of C. esculenta leaves for the first time.

Tannic acid supplementation in the diet of Holstein bulls: Impacts on production performance, physiological and immunological characteristics, and ruminal microbiota

This study was conducted to evaluate the influences of supplementing tannic acid (TA) at different doses on the production performance, physiological and immunological characteristics, and rumen bacterial microbiome of cattle. Forty-eight Holstein bulls were randomly allocated to four dietary treatments: the control (CON, basal diet), the low-dose TA treatment [TAL, 0.3% dry matter (DM)], the mid-dose TA treatment (TAM, 0.9% DM), and the high-dose TA treatment (TAH, 2.7% DM). This trial consisted of 7 days for adaptation and 90 days for data and sample collection, and samples of blood and rumen fluid were collected on 37, 67, and 97 d, respectively. The average daily gain was unaffected (P > 0.05), whilst the ruminal NH3-N was significantly decreased (P < 0.01) by TA supplementation. The 0.3% TA addition lowered (P < 0.05) the levels of ruminal isobutyrate, valerate, and tumor necrosis factor alpha (TNF-α), and tended to (P < 0.1) increase the gain to feed ratio. The digestibility of DM, organic matter (OM), and crude protein, and percentages of butyrate, isobutyrate, and valerate were lower (P < 0.05), while the acetate proportion and acetate to propionate ratio in both TAM and TAH were higher (P < 0.05) than the CON. Besides, the 0.9% TA inclusion lessened (P < 0.05) the concentrations of glucagon and TNF-α, but enhanced (P < 0.05) the interferon gamma (IFN-γ) level and Simpson index of ruminal bacteria. The 2.7% TA supplementation reduced (P < 0.05) the intake of DM and OM, and levels of malondialdehyde and thyroxine, while elevated (P < 0.05) the Shannon index of the rumen bacterial populations. Moreover, the relative abundances of the phyla Fibrobacteres and Lentisphaerae, the genera Fibrobacter and Bradyrhizobium, and the species Bradyrhizobium sp., Lachnospiraceae bacterium RM29, and Lachnospiraceae bacterium CG57 were highly significantly (q < 0.01) or significantly (q < 0.05) raised by adding 2.7% TA. Results suggested that the TA addition at 0.3% is more suitable for the cattle, based on the general comparison on the impacts of supplementing TA at different doses on all the measured parameters.

Effect of monosodium glutamate on serum sex hormones and uterine histology in female rats along with its molecular docking and in-silico toxicity

Monosodium glutamate (MSG) is commonly used worldwide as a food flavour enhancer by the food industry. The current study investigated the in vivo toxic effects of MSG on the uterus in adult female Sprague Dawley rats and in vitro using MCF-7 and MDA-MB-231 cells, computational toxicity and molecular docking. The average levels of progesterone and oestrogen in the MSG-treated animals significantly altered. Besides, the average uterine lumen area (μm²) was smaller than the control group. MSG showed high-affinity binding to acetylcholine receptors and disrupted the normal nerve signal with a predicted LD50 of 4500 mg/kg. MSG also demonstrated good binding affinity to human oestrogen receptors beta and some other proteins that have an oxidative stress role in the female reproductive organs. Therefore, a precaution should be taken when utilising this compound, especially for females under the risk factor of hormonal abnormality.

Tannic acid reduced apparent protein digestibility and induced oxidative stress and inflammatory response without altering growth performance and ruminal microbiota diversity of Xiangdong black goats

The present study was performed to evaluate the impacts of tannic acid (TA) supplementation at different levels on the growth performance, physiological, oxidative and immunological metrics, and ruminal microflora of Xiangdong black goats. Twenty-four goats were randomly assigned to four dietary treatments: the control (CON, basal diet), the low-dose TA group [TAL, 0.3 % of dry matter (DM)], the mid-dose TA group (TAM, 0.6 % of DM), and the high-dose TA group (TAH, 0.9 % of DM). Results showed that the growth performance was unaffected (P > 0.05) by adding TA, whilst the 0.3 % and 0.6 % TA supplementation significantly decreased (P < 0.05) the apparent digestibility of crude protein (CP) and ruminal NH3-N concentration, and raised (P < 0.05) the level of total volatile fatty acid (TVFA) in rumen. The increments of alanine aminotransferase (ALT), triglyceride (TG), cortisol (CORT), total antioxidant capacity (T-AOC), interleukin (IL)-1β, IL-6, and serumamyloid A (SAA), and decrements of globulin (GLB), immunoglobulin G (IgG), cholinesterase (CHE), glutathione reductase (GR), creatinine (CRE), growth hormone (GH), high-density lipoprotein cholesterol (HDLC), and insulin-like growth factor 1 (IGF-1) to different extents by TA addition were observed. Although the Alpha and Beta diversity of rumen bacterial community remained unchanged by supplementing TA, the relative abundance of the predominant genus Prevotella_1 was significantly enriched (P < 0.05) in TAL. It could hence be concluded that the TA supplementation in the present trial generally decreased CP digestion and caused oxidative stress and inflammatory response without influencing growth performance and ruminal microbiota diversity. More research is needed to explore the premium dosage and mechanisms of effects for TA addition in the diet of goats.

Is L-Glutamate Toxic to Neurons and Thereby Contributes to Neuronal Loss and Neurodegeneration? A Systematic Review

L-glutamate (L-Glu) is a nonessential amino acid, but an extensively utilised excitatory neurotransmitter with critical roles in normal brain function. Aberrant accumulation of L-Glu has been linked to neurotoxicity and neurodegeneration. To investigate this further, we systematically reviewed the literature to evaluate the effects of L-Glu on neuronal viability linked to the pathogenesis and/or progression of neurodegenerative diseases (NDDs). A search in PubMed, Medline, Embase, and Web of Science Core Collection was conducted to retrieve studies that investigated an association between L-Glu and pathology for five NDDs: Alzheimer's disease (AD), Parkinson's disease (PD), multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS), and Huntington's disease (HD). Together, 4060 studies were identified, of which 71 met eligibility criteria. Despite several inadequacies, including small sample size, employment of supraphysiological concentrations, and a range of administration routes, it was concluded that exposure to L-Glu in vitro or in vivo has multiple pathogenic mechanisms that influence neuronal viability. These mechanisms include oxidative stress, reduced antioxidant defence, neuroinflammation, altered neurotransmitter levels, protein accumulations, excitotoxicity, mitochondrial dysfunction, intracellular calcium level changes, and effects on neuronal histology, cognitive function, and animal behaviour. This implies that clinical and epidemiological studies are required to assess the potential neuronal harm arising from excessive intake of exogenous L-Glu.

Effects of monosodium glutamate on testicular structural and functional alterations induced by quinine therapy in rat: An experimental study

BACKGROUND

Quinine (QU) as an anti-malarial drug induces alterations in testicular tissue. Toxic effects of monosodium glutamate (MSG) on the male reproductive system have been recognized.

OBJECTIVE

To investigate the impact of MSG administration on the intensity of gonadotoxicity of QU.

MATERIALS AND METHODS

Sixty eight-wk old Wistar rats weighing 180-200 gr were divided into six groups (n = 10/each): the first group as a control; the second and third groups received low and high doses of MSG (2 & 4 gr/kg i.p.), respectively, for 28 days; the fourth group received QU for seven days (25 mg/kg); and in the fifth and sixth groups, QU was gavaged following the MSG administration (MSG + QU) from day 22 to day 28. Serum testosterone and malondialdehyde (MDA) levels were measured. Testes samples were prepared for tissue MDA levels, histomorphometry, and immunohistochemistry of p53. Sperm analysis was performed on cauda epididymis.

RESULTS

Serum and tissue MDA levels were increased in treated groups compared to the control group. This increment was higher in the MSG + QU groups. The testosterone levels were reduced significantly (p < 0.0001) in all treated groups. In addition, histomorphometric indices and tubular epithelium population were reduced significantly (p < 0.0001) in QU, MSG + QU, and consequently in high-dose MSG, QU, MSG + QU groups. All spermatogenic indices were reduced in the treated groups, particularly in the MSG + QU groups. Sperm motility and viability indices were reduced significantly (p = 0.003) in the MSG + QU groups. Finally, the overexpression of p53 was observed in the MSG + QU groups.

CONCLUSION

The administration of MSG before and during QU therapy may intensify testicular tissue alterations.

Natural product of gambier (Uncaria gambier Roxb) extracts to counter against hepatotoxicity effects due to monosodium glutamate induction in male mice

Monosodium glutamate (MSG) is often added in foods to enhance the flavor. It has adverse effect to body organs. Natural remedies, such as: gambier have been known for generations used to improve health. Substances contained in gambier, i.e.: catechins are believed to reduce the occurrence of hepatotoxicity. The study aims to analyze the effects of gambier in reducing the hepatotoxicity of MSG. This study with a posttest only control group design. Mice amount 25 (5 groups, n = 5/group). All interventions are given orally for 4 weeks. At the end of the study, it carried out euthanasia taken the liver of mice to made histopathology preparations then examine by light microscope, ×400, ×5 view field. Liver damage was found in each group with various levels of histological appearance:(I) 2 normal, 2 minimal, 1 moderate and none severe; (II) none normal, 1 minimal, 3 moderate and 1 severe; (III) 1 normal, 4 minimal, none moderate and severe;, (IV) 2 normal, 3 minimal, none moderate and severe; and (V) 4 normal, 1 minimal, none moderate, and severe. The data were analyzed using Kruskal-Wallis test. The level of liver damage among all groups was significantly different (p = 0.017). The same on the Dunn test also showed the level of liver damage in Group-II to compare with other groups (p < 0.05). The present study proves that Gambier (Uncaria gambier Roxb) can reduce occurrence of hepatotoxicity caused by MSG.

Ameliorative Effect of Graviola (Annona muricata) on Mono Sodium Glutamate-Induced Hepatic Injury in Rats: Antioxidant, Apoptotic, Anti-inflammatory, Lipogenesis Markers, and Histopathological Studies

Simple Summary

Food additives, especially monosodium glutamate (MSG), induces serious liver disorders. This study premeditated to investigate the effect of Graviola extract (GE) on hepatic and cellular alterations induced by MSG. Our result revealed that GE administration normalized the oxidative stress markers, as well as the proinflammatory cytokines, in addition to downregulation of the inducible nitric oxide synthase (iNOS) and FAS, hepatic fatty acid synthase, and led to the upregulation of the silent information regulator protein one (SIRT1) gene. This is the first report investigating the intracellular pathway and mechanism of Graviola extract’s action in alleviating the MSG supplementation injuries.

Abstract

Monosodium glutamate (MSG) is a widely used food additive, and there is a trepidation that MSG plays a critical role in multiple hepatic disorders. This study was planned to investigate Graviola extract (GE) effects on hepatic and cellular alterations induced by MSG. Fifty Wistar rats were randomly allocated into five groups: control (received normal saline), Graviola (received 200 mg/kg body weight), MSG (received 2.4 gm MSG/kg, 15% of Lethal dose (LD₅₀) of MSG), Graviola + monosodium glutamate (MSG + GE; received GE, 200 mg/kg/day and MSG 2.4 gm/kg body weight (BW) for the next four weeks), and monosodium glutamate + Graviola (received MSG only (2.4 gm/kg BW) daily for four weeks, then concomitant with Graviola (200 mg/kg BW) daily for the next four weeks. MSG and GR were administered orally for eight weeks. Our results showed that MSG caused a significant increase in oxidative stress markers malondialdehyde (MDA), reactive oxygen species (ROS), nitric oxide (NO), hydrogen peroxide (H₂O₂), proinflammatory cytokines interleukin 6 (IL-6) level, a tumor protein (P53), hepatic cellular damage, as well as proapoptotic markers caspase-3, and B-cell lymphoma 2 (BCL-2)-like protein 4 (Bax). A significant decrease in superoxide dismutase (SOD), catalase (CAT), glutathione S transferase (GST), reduced glutathione (GSH), and an antiapoptotic agent B-cell lymphoma 2 (BCl-2) was observed. The detected MSG effects were normalized by Graviola administration, either a prophylactic or protecting dose. Besides, Graviola reduced the expression of inducible nitric oxide synthase (iNOS) and hepatic fatty acid synthase (FAS) and led to the upregulation of the silent information regulator protein one gene expression gene (SIRT1).In conclusion, the results suggest that Gaviola’s interrelated antiapoptotic, antioxidant, and anti-inflammatory properties are potential mechanisms to enhance hepatic deficits and protect the liver. Graviola can, therefore, be considered a promising hepatoprotective supplement. Additionally, further human clinical trials are also necessary to validate the present research.

High-fat diet-induced obesity and impairment of brain neurotransmitter pool

Obesity and the brain are linked since the brain can control the weight of the body through its neurotransmitters. The aim of the present study was to investigate the effect of high-fat diet (HFD)-induced obesity on brain functioning through the measurement of brain glutamate, dopamine, and serotonin metabolic pools. In the present study, two groups of rats served as subjects. Group 1 was fed a normal diet and named as the lean group. Group 2 was fed an HFD for 4 weeks and named as the obese group. Markers of oxidative stress (malondialdehyde, glutathione, glutathione-s-transferase, and vitamin C), inflammatory cytokines (interleukin [IL]-6 and IL-12), and leptin along with a lipid profile (cholesterol, triglycerides, high-density lipoprotein, and low-density lipoprotein levels) were measured in the serum. Neurotransmitters dopamine, serotonin, and glutamate were measured in brain tissue. Fecal samples were collected for observing changes in gut flora. In brain tissue, significantly high levels of dopamine and glutamate as well as significantly low levels of serotonin were found in the obese group compared to those in the lean group (P > 0.001) and were discussed in relation to the biochemical profile in the serum. It was also noted that the HFD affected bacterial gut composition in comparison to the control group with gram-positive cocci dominance in the control group compared to obese. The results of the present study confirm that obesity is linked to inflammation, oxidative stress, dyslipidemic processes, and altered brain neurotransmitter levels that can cause obesity-related neuropsychiatric complications.

Natural products as safeguards against monosodium glutamate-induced toxicity

Monosodium glutamate is a sodium salt of a nonessential amino acid, L-glutamic acid, which is widely used in food industry. Glutamate plays an important role in principal brain functions including formation and stabilization of synapses, memory, cognition, learning, as well as cellular metabolism. However, ingestion of foodstuffs rich in monosodium glutamate can result in the outbreak of several health disorders such as neurotoxicity, hepatotoxicity, obesity and diabetes. The usage of medicinal plants and their natural products as a therapy against MSG used in food industry has been suggested to be protective. Calendula officinalis, Curcuma longa, Green Tea, Ginkgo biloba and vitamins are some of the main natural products with protective effect against mentioned monosodium glutamate toxicity through different mechanisms. This review provides a summary on the toxicity of monosodium glutamate and the protective effects of natural products against monosodium glutamate -induced toxicity.

Neuro-pharmacological evaluation of anticonvulsant and neuroprotective activity of Cocculus laurifolius leaves in wistar rats

The aim of the study was to evaluate the anticonvulsant and neuroprotective activity of Cocculus laurifolius D.C leaves in albino wistar rats against strychnine induced convulsions. Initially the extract was investigated for acute oral toxicity testing in order to examine any signs of toxicity and mortality. For anticonvulsant activity, the ethanolic extract was evaluated at doses 200 and 400 mg/kg, p.o. against strychnine induced convulsions model, at 1, 7, 15 and 30th day of treatment. Meanwhile, the neuroprotective effect of the extract was investigated via histopathological assessment. Cocculus laurifolius (200 and 400 mg/kg, p.o.) exhibited anticonvulsant activity as indicated by significant delay in the onset of convulsions and time to death after strychnine induced convulsions. Similarly, significant reduction in the duration of convulsions and percentage of mortality was observed by ethanolic extract (200 and 400 mg/kg p.o.) at 1, 7, 15 and 30th day of test sessions. Furthermore, Cocculus laurifolius leaves (200 and 400 mg/kg p.o.) also exhibited neuroprotective effect with considerable preserved neuronal structures and significant decrease in neuronal apoptosis, in comparison with control. The results obtained from the present study indicate that ethanolic extract of Cocculus laurifolius leaves possess potential anticonvulsant and neuroprotective effect against strychnine induced convulsions. Therefore, it can be concluded that Cocculus laurifolius leaves may be a valuable in management of epilepsy, however further studies are required on large number of animals to confirm these findings.