• Applied Biological Chemistry
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• v.43 no.1
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• pp.72-77
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• 2000

The repeated silica gel colum chromatographies of EtOAc fraction, showing anticonvulsant activity, obtained from MeOH extracts of Schizandra chinensis B. fruits led to isolation of a sesquiterpenoid, four lignans and a sterol glycoside. Their chemical structures were determined to be chamigrenal, gomisin A, gomisin H, gomisin N. schizandrin and daucosterol. Among them, schizandrin and daucosterol inhibited GABA degrative enzymes, succinic semialdehyde dehydrogenase and succinic semialdehyde reductase, respectively. It is postulated that the schizandrin and daucosterol are able to elevate the neurotransmitter GABA levels in central nervous system by inhibitory action on GABA degrative enzymes and act as anticonvulsant drugs.

• Korean Journal of Food Science and Technology
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• v.53 no.3
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• pp.245-251
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• 2021

We determined the quality characteristics, acrylamide concentration, and antioxidant activity of Nurungji prepared using white rice, brown rice, gamma-aminobutyric acid (GABA) brown rice, oats, and barley. The moisture content of Nurungji prepared using white rice was the lowest (1.48%) and the highest (6.53%) was obtained in barley Nurungji. The brightness (L^*) of white rice Nurungji was the highest, whereas that of GABA brown rice Nurungji was the lowest. The acrylamide concentration was the lowest (37.24 ㎍/g) in white rice Nurungji and the highest (255.50 ㎍/g) in oats Nurungji. The levels of total polyphenol and total flavonoid were the lowest in white rice Nurungji and high in oats and GABA brown rice Nurungji. The antioxidant activity was higher in Nurungji prepared using oats, GABA brown rice, brown rice, and barley than that using white rice. It is necessary to select an appropriate grain when preparing Nurungji by considering the amount of acrylamide produced.

• Food Science and Preservation
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• v.24 no.1
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• pp.134-144
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• 2017

This study evaluated the changes of physiochemical properties, phytochemical compounds (isoflavones and phenolic acids), and biological activity during the fermentation of Doenjang without and with bitter melon powder (BMP). The pH decreased from 6.41-5.83 to 5.81-5.24, during the fermentation of Doenjang, while the acidity increased from 0.42-0.65% to 1.28-1.48%. The viable cell numbers of Bacillus and Yeast, salinity, and total amino acid contents increased at the end fermentation (60 day). Also, the fermented Doenjang (FD) with 10% BMP showed the highest ${\gamma}$-aminobutyric acid (GABA, 129.87 mg/100 g) contents, among all the Doenjang samples. The FD exhibited significantly higher inhibitory activities than unfermented Doenjang (UFD) on radicals and ${\alpha}$-glucosidase. The phytochemical compounds including isoflavone-aglycones and phenolic acids increased, whereas isoflavoneglycosides decreased in the BM following fermentative processing. Moreover, the total phenolic, isoflavone-aglycone, and phenolic acid contents were markedly increased, leading to a general increase in antioxidant and ${\alpha}$-glucosidase inhibition activities after fermentation. These results suggest that BMP may be used to prepare a new type of fermented Doenjang with improved antioxidant and antidiabetic activities.

• BMB Reports
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• v.28 no.2
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• pp.162-169
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• 1995

Rat brain succinic semialdehyde dehydrogenase (EC 1.2.1.24 SSADH) activity was detected in mitochondrial, cytosolic and microsomal fractions. Brain mitochondrial soluble SSADH was purified by ammonium sulfate precipitation, DEAE Sephacel, and 5'-AMP Sepharose 4B affinity chromatography. The purified enzyme was shown to consist of four identical subunits, and the molecular weight of a subunit was 55 kD. The $K_m$ for short chain aliphatic aldehydes and aromatic aldehydes were at the $10^{-3}M$ level but that for succinic semialdehyde was 2.2 ${\mu}M$. Either $NAD^+$ or $NADP^+$ can be used as a cofactor but the affinity for $NAD^+$ was 10 times higher than that for $NADP^+$. The brain cytosolic SSADH was also purified by ammonium sulfate precipitation, DEAE Sephacel, Blue Sepharose CL-6B and 5'-AMP Sepharose 4B affinity chromatography and its Km for short chain aliphatic aldehydes was at the $10^{-3}$ level but that for succinic semialdehyde was 3.3 ${\mu}M$. $NAD^+$ can be used as a cofactor for this enzyme. We suppose that both enzyme might participate in the oxidation of succinic semialdehyde, which is produced during GABA metabolism. The activity of both cytosolic and mitochondrial SSADH was markedly inhibited when the concentration of succinic semialdehyde was high. The reciprocal plot pattern of product inhibition and initial velocity indicated a sequential ordered mechanism for mitochondrial matrix SSADH. Chemical modification data suggested that amino acid residues such as cysteine, serine and lysine might participate in the SSADH reaction.

• The Korean Journal of Physiology and Pharmacology
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• v.9 no.5
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• pp.255-262
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• 2005

Striatum is involved in the control of movement and habitual memory. It receives glutamatergic input from wide area of the cerebral cortex as well as an extensive serotonergic (5-hydroxytryptamine, 5-HT) input from the raphe nuclei. In our study, the effects of 5-HT on synaptic transmission were studied in the rat corticostriatal brain slice using in vitro whole-cell recording technique. 5-HT inhibited the amplitude as well as frequency of spontaneous excitatory postsynaptic currents (sEPSC) significantly, and neither ${\gamma}-aminobutyric$ acid (GABA)A receptor antagonist bicuculline (BIC), nor $N-methyl-_{D}-aspartate$ (NMDA) receptor antagonist, $_{DL}-2-amino-5-phosphonovaleric$ acid (AP-V) could block the effect of 5-HT. In the presence non-NMDA receptor antagonist, 2,3-dioxo-6-nitro-1,2,3,4-tetrahydrobenxo[f] quinoxaline-7-sulfonamide (NBQX), the inhibitory effect of 5-HT was blocked. We also figured out that 5-HT change the channel kinetics of the sEPSC. There was a significant increase in the rise time during the 5-HT application. Our results suggest that 5-HT has an effect on both pre- and postsynaptic site with decreasing neurotransmitter release probability of glutamate and decreasing the sensitivity to glutamate by increasing the rise time of non-NMDA receptor mediated synaptic transmission in the corticostriatal synapses.

• Korean Journal of Clinical Pharmacy
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• v.16 no.1
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• pp.63-68
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• 2006

Gabapentin, 1-(aminomethyl-1-cyclohexyl)acetic acid, is anew antiepileptic drug related to ${\gamma}-aminobutyric$ acid(GABA) currently being introduced in therapy worldwide. The bioavailability and pharmacokinetics of gabapentin capsules were examined in 22 volunteers who received a single oral dose in the fasting state by randomized balanced $2{\times}2$ crossover design. After dosing, blood samples were collected for a period of 24 hours and analyzed by liquid chromatography-tandem mass spectrometry (LC/MS/MS). Time course of plasma gabapentin concentration was analyzed with non-compartmental and compartmental approaches. $WinNonlin^{(R)}$, the kinetic computer program, was used for compartmental analysis. One compartment model with first-order input, first-order output with no lag time and weighting by $1/(predieted\;y)^2$ was chosen as the most appropriate pharmacokinetic model for the volunteers. The major pharmacokinetic parameters $(AUC_{0-24hr},\;AUC_{inf},\;C_{max}\;and\;T_{max})$ and other parameters $(K_a,\;K_{el},\;V_d/F\;and\;Cl/F)$ of $Gapentin^{TM}$ (test drug) and $Neurontin^{TM}$ (reference drug) were estimated by non-compartmental analysis and compartmental analysis. The 90% confidence intervals of mean difference of logarithmic transformed $AUC_{0-24hr}\;and\;C_{max}$ were $log(0.9106){\sim}log(1.l254)\;and\;log(0.8521){\sim}log(1.0505)$, respectively. It shows that the bioavailability of the test drug is equivalent with that of the reference drug. There was no statistically significant difference between the two drugs in all pharmacokinetic parameters.

• Biomolecules & Therapeutics
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• v.8 no.4
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• pp.325-331
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• 2000

The present study was designed to assess the role of spinal adenosine $A_2$ receptor in the regulation of cardiovascular functions such as mean arterial pressure (MAP) and heart rate (HR) in male Sprague-Dawley rats. Rats (250~300 g) were anesthetized with urethane and paralyzed with d-tubocurarine and artificially ventilated. blood pressure and HR were continuously monitored via a femoral catheter connected to a pressure transducer and a polygraph. Drugs were administered intrathecally using injection cannula through guide cannula which was inserted inthrathecally at lower thoracic level through a puncture of an atlantooccipital mombrane. Intrathecal injection of an adenosine $A_2$ receptor agonist, 5'-(N-cyclopropyl)-carboxamaidoadenosine (CPCA; 1, 2 and 3 nmol, respectively), produced a dose-dependent decrease in MAP and HR. Pretreatment with $N^{G}$-nitro-L-arginine methyl ester (L-NAME), a nitric oxide synthase inhibitor or 10 nmol of MDL-12,330, an adenylate cyclase inhibitor blocked significantly the depressor and bradycardic effect of 2 nmol of CPCA. But, Pretreatment with 3 nmol of bicuculline, gamma-aminobutyric acid A (GAB $A_{A}$) receptor antagonist, or 50 nmol of 5-aminovaleric acid, GAB $A_{B}$ receptor antagonist did not inhibit the depressor and bradycardic effect of 2 nmol of CPCA. These results indicate that adenosine $A_2$ receptor in the spinal cord plays an inhibitory role in the regulation of cardiovascular function and that the depressor and bradycardic action of adonosine $A_2$ receptor are mediated via the synthesis of nitric oxide and the activation of adenylate cyclase in the spinal cord of rats.s.s.s.

• Korean Journal of Food Science and Technology
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• v.53 no.5
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• pp.648-656
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• 2021

This study analyzed the physicochemical properties of Danyangju and Iyangju fermented using uncooked germinated brown rice. Total bacteria and yeast from Danyangju and Iyangju showed the maximal value on day 1 of fermentation, but their numbers decreased by the seventh day. On the seventh day, the total bacteria were higher in Iyangju than in Danyangju, but yeast was the lowest in Iyangju. Both Danyangju and Iyangju showed decreased whiteness in color, whereas redness and yellowness increased with fermentation. Sugar contents, reducing sugar, acidity, alcohol, and polyphenol contents increased during fermentation in both Danyangju and Iyangju; this increase was higher in Iyangju than in Danyangju. Iyangju and Danyangju showed gradual increases in α-diphenyl-β-picrylhydrazyl (DPPH) radical scavenging activity until day 5. The γ-aminobutyric acid (GABA) content increased with fermentation in Iyangju and Danyangju, and Iyangju showed over 10-fold increase after fermentation.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.9
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• pp.1295-1303
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• 2015

Berry fruits are rich in phytochemicals, including polyphenols, anthocyanins, phenolic acids, and organic acids, which are known to have beneficial effects on health. The aim of this study was to investigate chemical composition, functional constituents, and antioxidant activities of mulberry, black raspberry, raspberry, and blueberry cultivated in Korea. Acidity of the four berries ranged from 0.26% to 1.10%, and pH ranged from 3.3 to 5.2. Total mineral contents of the four berries ranged from 92.9 to 256.0 mg/100 g. Among the berries, mulberry contained the most abundant total free sugars, and glucose and fructose were the major sugars in the berries. Mulberry contained more than three times as much ${\gamma}-aminobutyric$ acid as the content of the other berries. Blueberry contained more free phenolic acid than the other berries. Especially, chlorogenic acids were the major free phenolic acids in blueberry. Black raspberry had the highest amount of polyphenols, anthocyanins, and flavonoids among the berries and showed the highest antioxidant activity.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.spc1
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• pp.133-138
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• 2006

To differentiate barley responses to drought and salt stress, barley seedlings at the second leaf stage were treated with 218 mM NaCl and 29.5% PEG6000 iso-osmotic to 218 mM NaCl for 6 days. Shoot fresh weight and leaf relative water content of barley seedlings were more reduced by drought compared to salt stress. Hydrogen peroxide content increased under both stress conditions, but its accumulation was more severe at 6 days after salt stress. The activity of ascorbate peroxidase, glutathione reductase (GR) and catalase (CAT) was enhanced until 4 days after salt stress. On the other hand, the activity of GR and CAT increased gradually until 6 days after drought. Among the amino acids measured in this study, the accumulation of glycine, arginine and GABA (${\gamma}-aminobutyric$ acid) was lower under salt stress than drought. However, considerably larger amount of proline was accumulated by salt stress. It is concluded that the antioxidant enzymes activity and amino acid content of barley seed-lings were differently regulated in response to the isoosmotic condition of salt and drought stress.