GABA Concentrations Research Articles

Dynamic changes in primary and secondary metabolites of monascal brown rice through γ-aminobutyric acid microcapsule supplementation and untargeted metabolomic analysis

Abstract This study aimed to study the effect of modification of monascal brown rice (MBR) solid-state fermentation through supplementation of γ-aminobutyric acid (GABA) microcapsules from the emulsification/internal gelation technique on dynamic changes in primary and secondary metabolites during 25-day fermentation to conduct metabolomic analysis. During MBR fermentation, the d50 values of GABA microcapsules increased due to their swelling during the MBR fermentation. The lowest encapsulation efficiency (EE%) and highest cumulative release (CR%) of GABA microcapsules found after 25 days of the fermentation were 40.18% and 89.13%, respectively. It was an interesting point that supplementation of microencapsulated GABA into MBR substrate could expand the stationary phase (days 10–20 of the fermentation) of M. purpureus growth curve compared to the control (days 10–15 of the fermentation). During the stationary phase, the concentrations of alanine, phenylalanine, arginine, tyrosine, and tryptophan in MBR fermentation with GABA microcapsule supplementation rose by more than 1.2-fold relative to the control, whereas linolenic acid, linoleic acid, and oleic acid demonstrated increases of over 1.24, 1.31, and 1.42-fold, respectively. Following a 25-day fermentation period, the maximum concentration of GABA detected in the MBR supplemented with GABA microcapsules was 1,267.13 mg/kg, in comparison to the control. Considering HCA and variable importance in projection (VIP), the primary metabolites MBR from GABA microcapsule supplementation positively correlated with days 10 and 15 of the fermentation but days 20 and 25 of the fermentation for the secondary metabolites. The significant metabolic pathways based on the primary and secondary metabolites of MBR from GABA microcapsule supplementation were 1. starch and sucrose metabolism, 2. neomycin, kanamycin, and gentamicin biosynthesis, 3. biosynthesis of unsaturated fatty acids, 4. phenylalanine, tyrosine, and tryptophan biosynthesis, 5. arginine and proline metabolism, 6. citrate cycle (TCA cycle), 7. fructose and mannose metabolism, and 8. pyruvate metabolism.

Investigating Neurometabolite Changes in Response to Median Nerve Stimulation.

Rhythmic median nerve stimulation (MNS) at 10Hz has been shown to cause a substantial reduction in tic frequency in individuals with Tourette syndrome. The mechanism of action is currently unknown but is hypothesized to involve entrainment of oscillations within the sensorimotor cortex. We used functional magnetic resonance spectroscopy (fMRS) to explore the dynamic effects of MNS on neurometabolite concentrations. Here, we investigated the effects of rhythmic and arrhythmic 10Hz MNS on glutamate (Glu) and GABA concentrations in the contralateral sensorimotor cortex in 15 healthy controls, using a blocked fMRS design. We used a Mescher-Garwood-semi-localized by adiabatic selective refocusing (MEGA-sLASER) sequence at 7 T. Our results show no difference in the difference-from-baseline measures between the two stimulation conditions. Looking at the effect of MNS over both conditions there is a trend for an initial increase in Glu/tCr (total creatine) followed by a decrease over time, whereas GABA/tCr decreased during each stimulation block. These results suggest that despite entrainment of oscillations during rhythmic MNS, there are no significant differences in the tonic neuromodulatory effects of rhythmic and arrhythmic stimulation. The reduction in Glu over the course of stimulation may reflect a decrease in the glutamatergic firing due to adaptation. This may make it less likely that an involuntary movement is generated during continuous stimulation.

Isolamento e seleção de bactérias lácticas produtoras de ácido γ-aminobutírico e aplicação na fermentação de suco de tomate enriquecido com GABA

ABSTRACT: Tomatoes (Solanum lycopersicum L.) are nutrient-rich fruits with a high glutamic acid content, making them a suitable source for producing γ-aminobutyric acid (GABA) through the action of lactic acid bacteria (LAB). LAB plays a pivotal role in lactic fermentation, enhancing the taste and nutritional value of food products, often contributing to their health benefits. This study isolated GABA-producing LAB from tomatoes and assessed their potential for producing GABA-enriched fermented tomato juice. The results indicated the isolation of 15 LAB strains from the samples of five different tomatoes. All of these strains demonstrated the capability to produce GABA, with levels ranging from 1.732 to 3.113 mg/mL, as determined using thin-layer chromatography (TLC). Through sequencing, the promising strain TO42, identified as Weissella cibaria, was selected for tomato juice fermentation. Furthermore, GABA-enriched tomato juice was successfully fermented at 15 °Brix for 72 h, resulting in the highest recorded GABA and lactic acid content of 9.185 ± 0.398 mg/mL and 13.05 ± 1.56 g/L, respectively.

Gamma-aminobutyric acid fermentation and its fermented extracts on α-glucosidase inhibition and anti-obesity effect.

Levilactobacillus brevis KCL010 was fermented in a simple medium containing 8% (w/v) of rice bran extract. We modified the carbon, nitrogen, and initial pH conditions using 10g/L of sucrose, 10g/L of yeast extract, and 5.0 of pH, respectively. To minimize the pH increase due to decarboxylation, we fermented 100mL of modified synthetic medium containing citrate-phosphate buffer (CPB, pH 5.0) of 25-200mM in 250mL Erlenmeyer flasks. After 72h of fermentation with 50mM CPB, the maximum GABA concentration and conversion efficiency were 3.42g/L and 22.39%. Furthermore, the potential α-glucosidase inhibitory activity, MTT assay, and oil red O staining were determined by fermented extracts of L. brevis KCL010. At the highest concentration of 500μg/mL, the α-glucosidase inhibition percentages for non-fermented rice bran (NFRB), rice bran fermented by L. brevis (RBFL), and GABA (analytical standard) extracts were 55.03%, 58.37%, and 59.48%, respectively. All extracts exceeded 80% viability, suggesting that there was no cytotoxic to 3T3-L1 adipocytes. The rice bran fermented by L. brevis (RBFL) extract shows a high inhibition of lipid accumulation by 29.33% compared to those of extracts.

Therapeutic potential of the extract of giant millipede Telodeinopus Canaliculatus on epileptogenesis and associated anxiety-like behavior.

The secretions of Telodeinopus canaliculatus, a giant millipede, are used in traditional medicine to treat epileptic seizures. Therefore, this work aimed to assess the antiepileptogenic- and anxiolytic-like effects of an extract of T. canaliculatu in mice. Forty-eight mice were divided into six groups of eight each and treated as follows: normal control group received distilled water (10ml/kg, p.o.); negative control group received received distilled water (10ml/kg, p.o.); positive control group received sodium valproate (300mg/kg, p.o.); and test groups received with the extract (30, 50, and 70mg/kg, p.o.). One hour later, all groups, except the normal control group (distilled water, 10ml/kg, i.p.), received a daily dose of pentylenetetrazole (25mg/kg, i.p) until the onset of tonic-clonic seizures on day 24. On day 26 of the experiment, anxious behaviors were assessed. The mice were subsequently sacrificed and brains were collected for neurochemical analyses. The extract (30, 50, 70mg/kg, p.o.) reduced (p < 0.001) the seizure severity. It also increased the latencies to the onset of seizures. In the elevated plus maze, the extract (50mg/kg) increased by 51% (p < 0.001) the time spent in the open arms. The extract (50mg/kg) increased GABA concentration by 28% (p < 0.01) and 37% (p < 0.001) respectively in the hippocampus and amygdala. Moreover, the extract (30mg/kg) decreased the concentration of malondialdehyde by 47% (p < 0.001) and 42% (p < 0.01) respectively in the same regions. The hydroethanolic extract of T. canaliculatus is endowed with antiepileptogenic and anxiolytic effects.

Determination of Amino Acids of Novel Food in Food by HPLC Coupled with Pre-Column Derivatization

A method for simultaneous determination of Theanine and γ-aminobutyric acid (GABA), as the novel food of amino acids, which was established using pre-column derivatization and high-performance liquid chromatography (HPLC). 4-Dimethylaminoazobe nzene-4′-sulfonyl chloride (DABS-Cl) is employed as the derivatization reagent with chromophore linked to Theanine and GABA, which lacks chromophore for DAD analysis in its pristine structure. After the detection wavelength was confirmed, the chromatographic and derivatization conditions were also optimized, including the chromatographic column, mobile phases and their gradient, derivatization temperature and time, the additive amount of buffer solution and derivatization reagent. Methodological verification showed that the derivant of Theanine (DABS-Theanine) and derivant of GABA (DABS-GABA) have good linearity in the range of 1–100 μg/mL, with correlation coefficients of 0.9996 and 0.9995, respectively. The recoveries for both amino acids were between 93.95% and 103.90%, with RSDs ranging from 0.99% to 3.93%. The limit of detection (LOD) was 0.6 mg/kg for Theanine and 0.2 mg/kg for GABA. The limit of quantification (LOQ) was 1.7 mg/kg for Theanine and 0.6 mg/kg for GABA. Furthermore, five commercial products containing Theanine or GABA in two matrices (candy and beverage) were analyzed by the proposed method for validation. The average contents of Theanine and GABA were in the range of 307.49–1312.13 mg/kg and 22.98–6744.55 mg/kg, respectively. The developed method features easy sample pretreatment, a simple derivatization system, good separation specificity, good repeatability, accuracy and reliability, and can meet the large-scale determination Theanine and GABA in various food substrates.

Effect of Salinity Stress on Gut-Brain-Gonad Axis in the Red-Eared Slider (Trachemys scripta elegans).

The red-eared slider (Trachemys scripta elegans) can adapt to brackish water, which can endanger its biodiversity. Spermatogonial stem cells (SSCs) are essential for establishing and maintaining spermatogenesis and are regulated by the gut-brain-gonad axis. However, the effect of salinity on SSCs is unclear. We investigated the influence of salinity stress on the composition of the gut microbiota in T. s. elegans to determine whether it regulates SSC self-renewal and differentiation via the gut-brain-gonad axis. Three salinity groups (0‰, 5‰, and 10‰) were used in this study, and samples were obtained after 6 months of feeding. The mRNA expression of self-renewing genes (GFRα-1, RAS, and ERK) and meiotic initiation genes (RARα, NRG3, and ERBB4) in SSCs decreased with increasing salinity, indicating that salinity affects renewal and differentiation. In addition, harmful bacteria such as Enterococcus and Clostridium were increased in the S10 group, and lower levels of g_norank_f_Eubacteriaceae were negatively associated with γ-aminobutyric acid (GABA), whereas higher Turicibacter levels were positively associated with GABA levels, resulting in increased GABA content in the S5 group. The results show that salinity affects the secretion of neurotransmitters in the brain and negatively regulates the synthesis of reproductive hormones by changing the composition of intestinal microorganisms and metabolites, which affect SSC function. In conclusion, salinity influences the reproductive ability of T. s. elegans through the gut-brain-gonad axis. This study provides a new perspective for understanding the adaptation of T. s. elegans to brackish water.

Whole-Genome Sequence Analysis of Flammulina filiformis and Functional Validation of Gad, a Key Gene for γ-Aminobutyric Acid Synthesis.

Flammulina filiformis is one of the widely produced edible fungi worldwide. It is rich in γ-aminobutyric acid (GABA), a non-protein amino acid with important physiological functions in humans. To investigate the functions of key genes in the GABA metabolic pathway of F. filiformis, we isolated the monokaryon Fv-HL23-1 from the factory-cultivated F. filiformis strain Fv-HL23 and then sequenced and assembled the genome using the PacBio Sequel and Illumina NovaSeq sequencing platforms. The results showed that the genome comprised 140 scaffolds with a total length of 40.96 Mb, a GC content of 49.62%, an N50 of 917,125 bp, and 14,256 protein-coding genes. Phylogenetic analysis based on the whole genome revealed a close evolutionary relationship of Fv-HL23-1 with Armillaria mellea, Lentinula edodes, and Schizophyllum commune. A total of 589 carbohydrate-active enzymes were identified in the genome of Fv-HL23-1, suggesting its strong lignocellulose degradation ability, and 108 CYP450 gene family members were identified, suggesting important functions such as resistance to stress, secondary metabolite synthesis, and growth and development. The F. filiformis proteins glutamate decarboxylase 1 (Ff-GAD1) and glutamate decarboxylase 2 (Ff-GAD2), which may be responsible for GABA synthesis, were identified by protein alignment. Molecular docking analysis showed that Ff-GAD2 may have better catalytic activity than Ff-GAD1. To verify the function of Ff-gad2, its heterologous expression in the mycelia of the mononuclear Hypsizigus marmoreus was analyzed. Compared with wild type, the GABA content of mycelia was increased by 85.40-283.90%, the growth rate was increased by 9.39 ± 2.35%, and the fresh weight was increased by 18.44 ± 7.57%. Ff-GAD2 may play a catalytic role in GABA synthesis. In addition, the expression of the full-length Ff-gad2 gene was increased by 7.96 ± 1.39 times compared with the exon expression level in H. marmoreus mycelia, suggesting that the intron may contribute to the heterologous expression of Ff-GAD2. Based on whole-genome sequencing, we analyzed the enzyme system related to the important life activities of F. filiformis, focusing on the function of Ff-GAD, a key enzyme in the GABA synthesis pathway. The results lay a foundation for elucidating the GABA metabolism pathway of edible fungi and developing targeted breeding strategies for GABA-producing edible fungi.

GABAA receptor π forms channels that stimulate ERK through a G-protein-dependent pathway.

The rare γ-aminobutyric acid type-A receptor (GABAAR) subunit π (GABRP) is highly expressed in certain cancers, where it stimulates growth through extracellular-regulated kinase (ERK) signaling by an uncharacterized pathway. To elucidate GABRP's signaling mechanism, we determined cryoelectron microscopy (cryo-EM) structures of GABRP embedded in native nanodiscs, both in the presence and absence of GABA. Structurally, GABRP homopentamers closely resemble heteropentameric GABAAR anion channels, transitioning from a closed "resting" state to an open "active" state upon GABA binding. However, functional assays reveal that GABRP responds more like a type-B metabotropic receptor. At physiological concentrations of GABA, chloride flux is not detected. Rather, GABRP activates a G-protein-coupled pathway leading to ERK signaling. Ionotropic activity is only triggered at supraphysiological GABA concentrations, effectively decoupling it from GABRP's signaling functions. These findings provide a structural and functional blueprint for GABRP, opening new avenues for targeted inhibition of GABA growth signals in GABRP-positive cancers.

Aromatherapy was used to explore the sedative and hypnotic effects of Moringa seed essential oil on insomnia rats.

Moringa is a type of plant that is used both for medicinal and food. Moringa seed (MS) are rich in volatile oil and have initially been employed to treat diseases of the nervous system. Insomnia, a prevalent neurological disorder, has led to this study's aim: to extract the essential oil from MS and analyze its potential to improve sleep. This study utilized petroleum ether for the thermal extraction of the essential oil from MS, which was then subjected to compositional analysis using Gas Chromatograph Mass Spectrometer (GC-MS). P-chlorophenyl alanine (PCPA) was used to induce an insomnia model in Sprague-Dawley (SD) rats. Following the successful establishment of the model, the MS essential oil was administered at concentrations of 10%, 5%, and 2.5% to investigate its sedative and hypnotic effects. The efficacy of the MS essential oil was assessed by observing the general condition of rats in each group, conducting an open field test, a pentobarbital sodium righting test, and measuring the serum 5-HT (5-hydroxytryptamine) levels and hypothalamic GABA (γ-aminobutyric acid) content. GC-MS analysis of the MS essential oil revealed a rich composition, including oleic acid, palmitoleic acid, stigmasterol, and γ-stigmasterol, among other substances. Through the assessment of the rats' general condition, behavioral tests, and blood biochemical assays, it was inferred that MS essential oil aromatherapy can reduce the rat's locomotor activity, increase their interest in activity and exploration, enhance the serum 5-HT levels, and elevate hypothalamic GABA content. Consequently, it can be concluded that MS essential oil has a sedative and hypnotic effect.

Sleep-enhancing effect of Hongcheon-hop (Humulus lupulus L.) extract containing xanthohumol and humulone through GABAA receptor

Ethnopharmacological relevanceThe bitter resins in hops (Humulus lupulus) modulate GABA receptors, leading to central nervous system suppression, which induces sedative effects and enhances sleep. Aim of the studyThis study intends to explore the sleep-enhancing properties of Hongcheon-hop extract, a hop native to Korea, by analyzing sleep structure and its mechanisms through EEG. Materials and methodsA pentobarbital-induced sleep model was used, along with EEG analysis to study sleep architecture. The receptor binding of Hongcheon-hop extract was analyzed using GABA receptor antagonists. ResultsThe extract contained 7.44 mg/g of xanthohumol, 133.04 mg/g of α-acids including 13.74 mg/g of humulone and 84.52 mg/g of β-acids. Administration of the extracts resulted in a dose-dependent enhancement of sleep duration. Both low (100 mg/kg) and high doses (200 mg/kg) of the extract increased non-rapid eye movement (NREM) sleep by enhancing δ wave sleep, which represents deep sleep. The extract exerted its sleep-promoting effects by binding to the γ-aminobutyric acid (GABA) binding site on GABAA receptor. In an insomnia model, low dose of the extract was more effective than the same dose of GABA in enhancing sleep. Administration of the extract for 3 weeks increased the expression and protein levels of 5-HT1A receptors in addition to GABAA receptor, and also increased the content of GABA in the brain. A mixture of xanthohumol (1.49 mg) and humulone (2.75 mg) within Hongcheon-hop extract (200 mg) exhibited a sleep-enhancing effect comparable to that of the extract. ConclusionThese findings suggest that Hongcheon-hop extract, which contains xanthohumol and humulone, improves sleep quality by increasing NREM sleep through the enhancement of δ-wave sleep via GABAA receptors. Hongcheon-hop shows potential as a natural therapeutic agent for treating insomnia and enhancing sleep.

Reactive astrocytes mediate postoperative surgery-induced anxiety through modulation of GABAergic signalling in the zona incerta of mice

BackgroundSurgery can induce severe neuroinflammation and negative emotional symptoms, such as anxiety-like behaviour. We studied whether reactive astrocytes in the zona incerta (ZI) mediate surgery-induced anxiety in mice. MethodsLaparotomy under isoflurane 1.5 vol% was used as a model in adult mice. The role of the ZI in surgery-induced anxiety was evaluated by behavioural tests, optical fibre recordings of neuronal activity, in vivo electrophysiological recordings, chemogenetics, and optogenetics. ResultsOperative mice showed increased anxiety-like behaviour. Immunostaining and optical calcium recording revealed that astrocytes were abnormally activated in the ZI. Pharmacologic (F3, 15=5.837, P=0.044) or genetic manipulation (open field test: t7.41=3.66, P=0.007; elevated plus maze [EPM]: t10=2.70, P=0.022) of astrocyte activation in the ZI relieved anxiety-like behaviour in surgery-treated mice. Compared with the sham group, the surgery group showed increased extrasynaptic GABA concentrations and decreased GABA transporter-3 (GAT-3) expression, and inactivation of GABAergic neurones in the ZI. Upregulating GAT-3 in ZI astrocytes (OFT: t10.83=2.91, P=0.014; EPM: t9.15=3.55, P=0.006) or activating the GABAergic projection from ZI to the median raphe nucleus (ZIGABA→median raphe nucleus) (EPM: entries: F1, 24=3.45, P=0.027; time: F1, 25=4.07, P=0.043) ameliorated surgery-induced anxiety. ConclusionsReactive astrocytes in the zona incerta mediate surgery-induced anxiety, possibly by regulating GAT-3-mediated GABA homeostasis and inactivating ZIGABA→median raphe nucleus projections in mice.

Effects of microwave vacuum drying on drying characteristics, quality attributes and starch structure of germinated brown rice

Germinated brown rice (GBR) has high nutritional and health-promoting value, but the influence mechanism of microwave vacuum drying (MVD) on the quality properties of GBR is still unclear. This study investigated the effects of MVD parameters including microwave intensities (9, 12, and 15 W/g), drying temperatures (50, 60, and 70 °C), and vacuum pressures (0.03, 0.05, and 0.07 MPa) on the drying characteristics, quality attributes and starch structure of GBR. A falling-rate phase dominated the MVD process of GBR and temperature-controlled MVD significantly preserved the GABA content in GBR. MVD caused microstructural changes with rearrangement and gelatinization of starch granules in GBR. For the GBR under MVD, increasing the drying temperature resulted in a significant decrease in enthalpy (ΔH) and an increase in the degree of starch gelatinization (DSG) (P < 0.05), however, no significant effect of microwave intensity and vacuum pressure on ΔH and DSG (P > 0.05) was found. MVD reduced the relative crystallinity but hardly changed the crystal type or formed functional groups of starch molecules in GBR. Overall, temperature-controlled MVD conduced to the final quality of GBR. This study may provide a potential method to improve the quality attributes of GBR in product development applications.

γ-Aminobutyric Acid Alleviates Salinity-Induced Impairments in Rice Plants by Improving Photosynthesis and Upregulating Osmoprotectants and Antioxidants

Salt stress is a significant abiotic stress that hinders the growth of rice (Oryza sativa L.) and reduces their yield. Previous research has examined the synthesis of γ-aminobutyric acid (GABA) and its role in plant resistance under various abiotic stresses. However, the synthesis of GABA and its ability to mitigate damage caused by salt stress—particularly its effects on osmotic adjustment, antioxidant defense, photosynthesis, and overall plant growth throughout the entire rice lifecycle—remains unclear. Therefore, we conducted two experiments using salt-tolerant rice cultivar Lianjian 5 (J-5) and salt-susceptible cultivar Lianjing 7 (L-7). In Experiment I, RNA-seq (RNA sequencing) was used to analyze the differential expression of the transcriptome between CK and salinity treatments, revealing the key roles of GABA in salt tolerance. In Experiment II, different levels of exogenous GABA were applied to salt-stressed plants to investigate its physiological role in enhancing salt tolerance. Therefore, RNA-seq (RNA sequencing) was used to analyze the differential expression of the transcriptome between CK and salinity treatments, revealing the key roles of GABA in salt tolerance. Subsequently, different levels of exogenous GABA were applied to salt-stressed plants to investigate its physiological role in enhancing salt tolerance. We measured the activities of superoxide dismutase, peroxidase, and catalase, as well as photosynthetic characteristics such as photosynthesis, transpiration, chlorophyll content, stomatal density and size, and leaf anatomical features. The RNA-seq analysis revealed that GABA production is enhanced via the glutamate decarboxylase (GAD) gene (LOC4333932) in the salt-resistant rice cultivar. Exogenous GABA application improves salt-stress tolerance by increasing endogenous ABA and GABA contents, which enhance osmotic adjustment, boost antioxidant defenses, and regulate ion balance. These combined effects help maintain photosynthetic efficiency and support overall plant growth under salt-stressed environments. Additionally, the increased proportion of mesophyll cell periphery covered by chloroplasts (Sc/Sm) indicated enhanced mesophyll conductance. These helped maintain photosynthesis under saline conditions while reducing water consumption.

Sida corymbosa prevents seizures and memory deficit via inhibition of oxidative stress and neuronal loss in the hippocampus

Mesiotemporal lobe epilepsy is the most refractory form of epilepsy. The management of this condition relies on the use of antiepileptic drugs known to provide symptomatic relief. Herbal remedies are therefore an alternative to finding a cure for epilepsy. The present study aimed to assess the antiepileptic and anti-amnesic effects of Sida corymbosa aqueous extract using the pentylenetetrazole (PTZ) kindling model in rats. For this, 48 rats were divided into 6 groups of 8 animals each and treated as follows: normal and negative controls received per os (p.o) distilled water (10 mL/kg); experimental groups received S. corymbosa extract (17.14, 34.28, and 68.56 mg/kg, p.o); and positive control group received levetiracetam (250 mg/kg, p.o). One hour after the treatments, animals intraperitoneally (i.p) received a subconvulsive dose of PTZ (25 mg/kg), except the normal control group. The animals were treated once daily until the onset of the first tonic-clonic seizure (stage 5) in the negative control group. Twenty-four hours following the onset of the first seizure, memory impairment was assessed. Twenty-four hours later, the animals were sacrificed, and the hippocampus and prefrontal cortex were collected for biochemical analyses. The extract (68.56 mg/kg) prevented (p < 0.001) seizures from day 1 to day 12 compared to the negative control group. The extract (17.14 and 34.28 mg/kg) increased the recognition index by 80 % (p < 0.05) and 60 % (p < 0.01), respectively, compared with the negative control group. Moreover, the extract (17.14 mg/kg) increased by 68 % (p < 0.001) the concentration of GABA in the hippocampus. The extract (17.14 and 34.28 mg/kg) increased the acetylcholine level by 51 % (p < 0.001) and 69 % (p < 0.001) in the hippocampus, respectively. The extract at a dose of 17.14 mg/kg decreased the concentration of MDA in the hippocampus by 43 % (p < 0.001). These findings suggest that the extract has antiepileptic and anti-amnesic potentials that could justify its empirical use.

Optimization of Germination Conditions for Enriched γ-Aminobutyric Acid and Phenolic Compounds of Foxtail Millet Sprouts by Response Surface Methodology.

The optimum germination conditions for foxtail millet sprouts enriched with γ-aminobutyric acid (GABA) and antioxidant polyphenols were investigated. From single-factor experimental results, both the GABA level and total phenolic content (TPC) were more significantly affected by soaking temperature and time, and concentration of sucrose culture solution. Response surface methodology (RSE) was used to optimize the germination conditions of foxtail millet sprouts, where the interaction between soaking temperature and sucrose concentration exhibited a significant (p < 0.05) effect on TPC, and the interaction between soaking time and sucrose concentration displayed a significant (p < 0.05) effect on GABA content. The optimal germination conditions for TPC and GABA enrichment of foxtail millet sprouts were soaking at 31 °C for 4.5 h and germinating at 35 °C with 4.5 g/L sucrose solution for 5 days. Under the optimized conditions, the TPC and GABA content of foxtail millet sprouts were 926.53 milligrams of ferulic acid equivalents per 100 g dry weight (mg FAE/100 g DW) and 259.13 mg/kg, separately, with less difference from the predicted values of 929.44 mg FAE/100 g DW and 263.60 mg/kg, respectively. Collectively, all the individual phenolic compounds increased significantly (p < 0.05) by optimization, except for cis-p-coumaric acid and cis-ferulic acid in bound. The results provide a practical technology for suitable germination conditions to improve the health components of foxtail millet sprouts and increase their added value.

Advances in Plant GABA Research: Biological Functions, Synthesis Mechanisms and Regulatory Pathways.

The γ-aminobutyric acid (GABA) is a widely distributed neurotransmitter in living organisms, known for its inhibitory role in animals. GABA exerts calming effects on the mind, lowers blood pressure in animals, and enhances stress resistance during the growth and development of plants. Enhancing GABA content in plants has become a focal point of current research. In plants, GABA is synthesized through two metabolic pathways, the GABA shunt and the polyamine degradation pathway, with the GABA shunt being the primary route. Extensive studies have investigated the regulatory mechanisms governing GABA synthesis. At the genetic level, GABA production and degradation can be modulated by gene overexpression, signaling molecule-induced expression, transcription factor regulation, and RNA interference. Additionally, at the level of transporter proteins, increased activity of GABA transporters and proline transporters enhances the transport of glutamate and GABA. The activity of glutamate decarboxylase, a key enzyme in GABA synthesis, along with various external factors, also influences GABA synthesis. This paper summarizes the biological functions, metabolic pathways, and regulatory mechanisms of GABA, providing a theoretical foundation for further research on GABA in plants.

Reduction of soybean globulin antigen by soybean protein isolate/γ-aminobutyric acid complexes: Effect of the different concentrations of γ-aminobutyric acid on the protein modification, antigen levels, and foaming properties

Soybean flour has received increasing attention because of its unique nutritional properties. However, potential allergies to soy protein limit its application. This study aims to investigate the impact of various concentrations of γ-aminobutyric acid (GABA) on the secondary structure, foaming properties, and antigenicity of soybean protein obtained from soybean flour under thermal sterilisation. GABA increased the content of α-helix, reduced β-turn and random coil in soybean protein. The results indicated that after heating treatment, the concentration of GABA significantly affects the spatial conformation of soybean protein isolates (SPI). When the concentration of GABA was 0.40% (w/v), the particle size, zeta potential, and surface hydrophobicity of the SPI were the lowest, whereas the disulfide bond content was the highest. Multi-spectral technologies indicated that adding 0.40% GABA could assemble the system in a relatively stable manner. Moreover, the rigid structure of the protein was destroyed. This structural change significantly reduced the foaming and allergy of the protein. Adding 0.40% GABA could reduce the β-conglycinin antigen concentration from 24.26 mg/mL to 4.43 mg/mL. This study provides new insights into the production of new low-allergenic soybean flour. Additionally, it offers an assurance for the safe consumption of soybeans by individuals with allergies.

Enhancement of γ-aminobutyric acid content in Huangjiu through rice bran fermentation and its impact on the volatile organic compounds

Rice bran has high glutamic acid decarboxylase (GAD) activity and can be used to enrich and produce γ-aminobutyric acid (GABA). Glutinous rice was used as raw material to brew Huangjiu by liquefaction fermentation. Rice bran extract was added at different fermentation stages, then the content of GABA and basic physicochemical properties were tested, the changes of flavor substances and volatile organic compounds (VOCs) were observed in Huangjiu. The results showed the addition of concentrated GABA-enriched rice bran extract during the post-fermentation stage significantly increases the GABA content in Huangjiu. When the amount of rice bran used is 50 g, the GABA content in the Huangjiu can reach 592.44 mg/L after fermentation. The total sugar and pH of Huangjiu fermented with rice bran extract were higher than the control group, and the total acid and non-sugar solids were lower than the control group. Electronic tongue analysis showed that the addition of rice bran extract would affect the sourness, umami and saltiness taste of Huangjiu. Gas Chromatography-Ion Mobility Spectrometry (GC-IMS) analysis of Huangjiu made by adding rice bran extract at the post-fermentation stage showed increased isoamyl acetate, 2-heptanol, and other substances in comparison with the control group. The results of the study provide a cost-effective and rapid method for increasing the GABA content in Huangjiu. It also offers a theoretical basis and scientific guidance for the production of health-oriented Huangjiu.

Impact of levetiracetam and ethanol on memory, selected neurotransmitter levels, oxidative stress parameters, and essential elements in rats

BackgroundEthanol disrupts brain activity and memory. There is evidence supporting the beneficial effect of levetiracetam on alcohol consumption. Therefore, the aim of the study was to examine whether levetiracetam has a protective activity against ethanol-induced memory impairment, alterations in selected neurotransmission activities, oxidative stress, and selected essential elements in rats.MethodsThe rats were given levetiracetam (300 mg/kg b.w. po) with ethanol for three weeks prior to behavioral tests. Spatial memory was tested using the Morris water maze, while recognition memory was evaluated using the Novel object recognition test. The GABA and glutamate concentration was determined in three rat brain regions (cerebellum, hippocampus, and cerebral cortex). Serum oxidative stress parameters and selected essential elements concentration (Cu, Mn, Zn, Fe, Mg) in the rat brain were analyzed.ResultsLevetiracetam administered with ethanol improved spatial memory, but did not affect abstinence-induced impairment. The drug also decreased ethanol-induced long-term recognition memory impairment. No alterations in glutamate levels were observed. GABA levels were elevated by levetiracetam in the cerebral cortex and by ethanol in the cerebellum. Ethanol increased catalase activity (CAT) and decreased superoxide dismutase activity (SOD) in the serum. Levetiracetam significantly increased the activity of SOD. Alcohol disrupted the levels of trace elements (Mn, Zn, Mg) in the rat brain. Additionally, levetiracetam alone increased Mg, Fe, and Cu concentrations while all animals receiving the drug also had significantly lower concentrations of Zn.ConclusionsLevetiracetam had differential effects against ethanol-induced impairments. These findings could have important implications for future levetiracetam treatment in patients.