• Korean Journal of Pharmacognosy
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• v.39 no.4
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• pp.324-329
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• 2008

Aldose reductase (AR), the key enzyme in the polyol pathway, plays an important role in the pathogenesis of diabetic complications such as cataract formation. AR inhibitors (ARI) can prevent or reverse early abnormalities in diabetic complications. However, none of ARI has achieved worldwide use because of limited efficacy or undesirable side effects. Therefore, evaluating natural sources for ARI potential may lead to the development of safer and more effective agents against diabetic complications. 49 Vietnam herbal medicines have been investigated with an in vitro evaluation system using aldose reductase inhibitory activities. Of these, 7 herbal medicines, Artemisia annua (leaf, stem), Duranta repens (leaf, stem), Excoecaria cochinchinensis (aerial part), Flueggea virosa (leaf, stem), Khaya senegalensis (leaf), Polygonum orientale (aerial part), Toxicodendron succedanea (leaf, stem) exhibited a significant inhibitory activity against aldose reductase. Particularly, Duranta repens (leaf, stem) and Toxicodendron succedanea (leaf, stem) showed two times more potent inhibitory activity than the positive control, 3.3-tetramethyleneglutaric acid (TMG).

• THE JOURNAL OF KOREAN ORIENTAL ONCOLOGY
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• v.2 no.1
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• pp.75-90
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• 1996

This experiment was designed to study the antitumor effects and Activity of Natural Killer Cell of semen Tiglii plus Rhizoma Rhei. The cytotoxic and antitumor effects were evaluated on human cell lines(A549, Caki-1, LL2, Sarcoma 180, NIH/3T3) after exposure to prebrewed Semen Tiglii plus Rhizoma Rhei water extract 0.1, 0.2, 0.4, 0.8, 1.6mg/ml using in MTT assay, LDH, colony forming efficency and SRB assay which were regarded as a valuable method for cytotoxic and antitumor effects of unknown compound on tumor cell lines. The results obtained in this studies were as follows. 1. From the result of MTT assay, the cytotoxicity of ST(生巴豆霜), ST+RR(生巴豆霜加大黃) were concentration-dependently increased in both group of the ST and ST+RR, the cytotoxicity of ST+RR(生巴豆霜加大黃) was similar to that of ST(生巴豆霜). 2. From the result of LDH, the cytotoxicity of ST, ST +RR were concentrati -on-dependently increased in both group of the ST and ST+RR, the cytotoxicity of ST+RR was similar to that of ST. 3. The antitumor effect on A549 tumor cell from the result of colony forming efficiency showed the inhibitory effect on the growth in both group of the ST and ST+RR, the inhibitory effect on growth was low slightly in the ST+RR. 4. From the result of SRB assay, the antitumor effect on caki-1 tumor cell of ST, ST+RR showed the inhibitory effect on the growth in both group of the ST and ST+RR, the antitumor effect of ST+RR was similar to that of ST. 5. Median survival time and increased life span were increased slightly in both group of the ST and ST+RR. 6. The inhibitory effect on the growth of Sarcoma 180 and Lewis lung carcinoma tumor cell were increased slightly in both group of the ST and ST+RR. 7. The activity of NK cell was increased in the ST+RR.

• The Korean Journal of Physiology and Pharmacology
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• v.18 no.6
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• pp.517-524
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• 2014

Phasic and tonic ${\gamma}$-aminobutyric acidA ($GABA_A$) receptor-mediated inhibition critically regulate neuronal information processing. As these two inhibitory modalities have distinctive features in their receptor composition, subcellular localization of receptors, and the timing of receptor activation, it has been thought that they might exert distinct roles, if not completely separable, in the regulation of neuronal function. Inhibition should be maintained and regulated depending on changes in network activity, since maintenance of excitation-inhibition balance is essential for proper functioning of the nervous system. In the present study, we investigated how phasic and tonic inhibition are maintained and regulated by different signaling cascades. Inhibitory postsynaptic currents were measured as either electrically evoked events or spontaneous events to investigate regulation of phasic inhibition in layer 2/3 pyramidal neurons of the rat visual cortex. Tonic inhibition was assessed as changes in holding currents by the application of the $GABA_A$ receptor blocker bicuculline. Basal tone of phasic inhibition was maintained by intracellular $Ca^{2+}$ and $Ca^{2+}$/calmodulin-dependent protein kinase II (CaMKII). However, maintenance of tonic inhibition relied on protein kinase A activity. Depolarization of membrane potential (5 min of 0 mV holding) potentiated phasic inhibition via $Ca^{2+}$ and CaMKII but tonic inhibition was not affected. Thus, phasic and tonic inhibition seem to be independently maintained and regulated by different signaling cascades in the same cell. These results suggest that neuromodulatory signals might differentially regulate phasic and tonic inhibition in response to changes in brain states.

• The Journal of Korean Obstetrics and Gynecology
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• v.27 no.2
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• pp.59-70
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• 2014

Purpose: This study was conducted to evaluate the inhibitory effect of ursolic acid from Prunella vulgaris on osteoclast differentiation. Methods: MTT-assay was performed to estimate cytotoxicity of ursolic acid from Prunella vulgaris in BMMs stimulated with M-CSF. TRAP staining, TRAP activity and Real-time PCR were performed to know the inhibitory effect on osteoclast differentiation. Actin ring formation were analysed to observe the effect of ursolic acid from Prunella vulgaris. Results: Ursolic acid from Prunella vulgaris has no cytotoxicity at the concentration of $1{\mu}g/ml$ or lower. Ursolic acid decreased the number of TRAP positive cells and the expression of NFATc1 gene, c-Fos gene, TRAP and OSCAR in BMMs stimulated with RANKL. Ursolic acid restrained the formation of actin ring. Ursolic acid inhibited NF-${\kappa}B$ activity by inducing degradation of p-$IkB{\alpha}$. Conclusions: Ursolic acid from Prunella vulgaris has the inhibitory effect of osteoclast differentiation and bone resorption. Futher studies are needed to treat osteoporosis by usolic acid from Prunella vulgaris.

• Korean Journal of Medicinal Crop Science
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• v.28 no.1
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• pp.21-28
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• 2020

Background: Owing to its high efficiency in lipid and protein production, peanut (Arachis hypogaea L.) is considered one of most important crops world-wide. The kernels of peanuts are undoubtedly the most important product this plant, whereas the skin is almost completely neglected in nutraceutical terms. However, peanut skin contains potentially health-promoting phenolics and dietary fiber, and there is considerable potential for commercial exploitation. In this study, we evaluated the α-glucosidase inhibitory activity of an extract of peanut skin (PS). Methods and Results: The α-glucosidase inhibitory effects of 80% ethanol extracts of peanut (A. hypogaea L. 'Sinpalkwang') skin were evaluated and found to have a half-maximal inhibitory concentration (IC₅₀) value of 1.2 ㎍/㎖. Progress curves for enzyme reactions were recorded spectrophotometrically, and the inhibition kinetics revealed time-dependent inhibition with enzyme isomerization. Furthermore, using ultra-high performance liquid chromatography combined with quadrupole-orbitrap mass spectrometry, we identified 26 compounds in the peanut skin extract, namely, catechin, epicatechin, and 24 proanthocyanidins. Conclusions: The results suggest that peanut skin can be utilized as an effective source of α-glucosidase inhibition in functional foods and nutraceuticals.

• Journal of Physiology & Pathology in Korean Medicine
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• v.16 no.6
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• pp.1230-1235
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• 2002

This study was conducted to evaluate the effects of Glycyrrhizae Radix water extract, known as depigmenting agent, on melanin biosynthesis in cellular level. The inhibitory effect of Glycyrrhizae Radix water extract on melanogenesis was identified by mushroom tyrosinase assay, To determine whether Glycyrrhizae Radix water extract suppress melanin synthesis in cellular level, B16 mouse melanoma cells were cultured in the presence of different concentrations of Glycyrrhizae Radix water extract. The maximum concentration of Glycyrrhizae Radix water extract that was not inhibitory to growth of the cells was 2 mg/ml. At that concentration, melanin synthesis was significantly inhibited without cytotoxicity after 5 days, compared with untreated cells. The treatment with Glycyrrhizae Radix water extract reduced tyrosinase and DOPAchrome tautomerase activity in a dose-dependent manner. These results suggest that the inhibitory effect of Glycyrrhizae Radix water extract on melanogenesis is due to the suppression of tyrosinase and DOPAchrome tautomerase activity.

• Korean Journal of Pharmacognosy
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• v.39 no.3
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• pp.165-173
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• 2008

Aldose reductase (AR), the principal enzyme of the polyol pathway, has been shown to play an important role in the diabetic complications, including diabetic cataract. The inhibitors of AR, therefore, would be potential agents for prevention of diabetic complications. As part of our ongoing project directed toward the discovery of preventive and/or treatment for diabetic complications, 48 Korean herbal medicines have been investigated with an in vitro evaluation system using aldose reductase inhibitory activities. Of these, 12 herbal medicines exhibited a significant inhibitory activity against aldose reductase. Particularly, seven herbal medicines, i.e., Eurya japonica, Chrysanthemum indicum, Akebia quinata, Saururus chinensis, Catalpa bignonioides, Lonicera japonica, Vitex rotundifolia showed two times more potent inhibitory activity than the positive control 3.3-tetramethyleneglutaric acid (TMG). In addition, Catalpa bignonioides showed the retardation of cataract-opacification of the lens of the eye under diabetic condition by xylose. Therefore, this result may provide a potential therapeutic approach for preventing and treating diabetic cataracts.

• Korean Journal of Pharmacognosy
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• v.30 no.1
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• pp.74-78
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• 1999

Nine sesquiterpene lactones, which were isolated from Hemisteptia lyrata Bunge, Chrysanthemum zawadskii Herbich var. latilobum Kitamura and Chrysanthemum boreale Makino were evaluated for the inhibition upon the nitric oxide release from the Raw cell and for the ACAT (acyl Co A: cholesterol acyltransferase) inhibitory assay. In the nitric oxide release inhibitory experiment, hemistepsin B $(IC_{50}\;=\;0.05\;{\mu}g/ml,\;0.15\;{\mu}M),$ cumambrin B, tulipinolide and costunolide exhibited strong inhibition with $IC_{50}$ values $0.05\;{\mu}g/ml\;(0.15\;{\mu}M),\;0.1\;{\mu}g/ml\;(0.38\;{\mu}M),\;0.2\;{\mu}g/ml\;(0.69\;{\mu}M)$ and $0.2\;{\mu}g/ml(0.86\;{\mu}M),$ respectively. In the ACAT inhibitory assay, angeloylcumambrin B, tigloylcumambrin B, tulipinolide and costunolide exhibited strong inhibition with $IC_{50}$ values $33\;{\mu}g/ml\;(95.4\;{\mu}M),\;22\;{\mu}g/ml\;(63.6\;{\mu}M),\;38\;{\mu}g/ml\;(151\;{\mu}M)$ and $17\;{\mu}g/ml(73.3\;{\mu}M),$ respectively, whereas other compounds did not exhibit significant activity against ACAT above $100\; {\mu}g/ml.$.

• Korean Journal of Pharmacognosy
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• v.26 no.4
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• pp.355-359
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• 1995

To find serotonin(5-hydroxytryptamine, 5-HT)-antagonizing activities in traditional herbal drugs, crude extracts from 66 kinds of traditional herbal drugs were randomly screened for inhibitory effects on 5-hydroxytryptophan(HTP)-induced diarrhea in mice. Intraperitoneal injection of 5-HTP(2.5 mg/kg) induced diarrhea in 92% of mice, when observed from 10 to 15 min after injection. Crude extracts(2 g/kg) from 66 kinds of traditional herbal drugs were orally pretreated for 1 h before 5-HTP injection. Of the 66 herbal drugs screened, Ephedrae Herba(麻黃), Cimicifugae Rhizoma(升麻), Anisi stellati Fructus(八角茴香), Aurantii Fructus(枳實), Polygalae Radix(遠志) showed the most potent inhibiting activities against 5-HTP(2.5 mg/kg)-induced diarrhea in mice. There are at least 3 possible mechanisms that would be responsible for the inhibitory effect of crude extracts on 5-HTP-induced diarrhea; 1) crude extract-induced inhibition of the activity of aromatic aminoacid decarboxylase catalyzing the conversion of 5-HTP to 5-HT, 2) crude extract-induced blockade of 5-HT receptor(s) in the gastrointestinal tract responsible for 5-HTP-induced diarrhea, 3) crude extract-induced inhibition of gastrointestinal activity, irrespective of 5-HT system. The exact mechanisms and molecules, responsible for the inhibitory effect of crude extracts on 5-HTP-induced diarrhea remain to be clarified.

• Journal of Society of Preventive Korean Medicine
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• v.7 no.2
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• pp.65-74
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• 2003

Objective : The aim of present study is to evaluate the inhibitory potential of licorice extract and glycyrrhizin on cytochrome P450(CYP) in human liver microsomes. Methods : Using human liver microsomes, water extract of licorice and glycyrrhizin as an inhibitor were co-incubated with each probe drug representing selective CYP isoform activity. We measured relative metabolic activity in incubation condition compared to that with no extract of licorice using HPLC system. Results : Both water extracts of licorice and glycyrrhizin showed inhibitory effect on CYP-catalyzed reactions. CYP2C19 $(IC_{50}=126.7{\mu}g/ml)$ is most potently inhibited by water extract than other tested CYP isoforms$(IC_{50}>450{\mu}g/ml)$, but glycyrrhizin exhibited potent inhibition on CYP1A2$(IC_{50}=106.9{\mu}g/ml)$ followed by CYP2C9 and CYP2D6. Conclusion: These results indicate that water extract of licorice and glycyrrhizin have inhibitory potential on CYP-catalyzed reaction in human liver microsomes. But the mechanism of inhibition was slightly different between them Water extract of licorice mainly inhibited CYP2C19, and glycyrrhizin primarily inhibited CYP1A2. The inhibition by water extract of licorice and glycyrrhizin on CYP isoforms may cause drug interaction with co-administered drug leading to toxicity or treatment failure.