• 대한의생명과학회지
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• 제12권4호
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• pp.385-391
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• 2006

Heterotrimeric GTP binding proteins (G proteins) mediate signals generated by neurotransmitters and hormones Among G proteins, Go is found in a large quantity in brain and growth cone membranes of neurons. In spite of its abundance in neurons, the role of Go is not fully understood. In our previous study, we identified promyelocytic leukemia zinc finger protein (PLZF) as an interacting partner of alpha subunit of Go ($Go{\alpha}$) and confirmed their interaction employing several biochemical assays. To date, it is reported that PLZF functioned as a cell growth suppressor and a transcription repressor. To determine effect of $Go{\alpha}$ and PLZF interaction on the cellular function of PLZF, we performed luciferase reporter gene assay and BrdU incorporation assay. Co-expression of $Go{\alpha}$ and PLZF synergistically increased the effect of PLZF alone. These results suggest that $Go{\alpha}$ may act as cellular activator of PLZF. This novel feature of Go may provide insights into understanding diverse role of Go-coupled receptor as well as its cellular actions.

• 생약학회지
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• 제47권1호
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• pp.24-28
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• 2016

This study was to evaluate the effect of ginseng (Panax ginseng) seed oil on the ${\alpha}$-glucosidase and ${\alpha}$-amylase. Each ginseng seed oils (HE, SE, EE) exhibited a significant inhibitory effect (p<0.001) at all concentrations (10 and 20 mg/ml) on ${\alpha}$-glucosidase activity. HE is the highest inhibitory activity (86.92%) at a concentration of 20 mg/ml, SE and EE showed an inhibitory effect of 77.13% and 65.83%, respectively. And also, Each ginseng seed oils (HE, SE, EE) exhibited a significant inhibitory effect (p<0.001) at all concentrations (1 and 2 mg/ml) on ${\alpha}$-amylase activity. HE is the highest inhibitory activity (89.68%) at a concentration of 2 mg/ml, SE and EE showed an inhibitory effect of 76.99% and 65.70%, respectively.

• 생약학회지
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• 제30권2호
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• pp.216-221
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• 1999

The NAD(P)-linked $3{\alpha}-Hydroxysteroid$ $dehydrogenase(3{\alpha}-HSD)$ of rat liver cytosol is powerfully inhibited by the non-steroidal anti-inflammatory drugs in rank-order of their therapeutic potency, and this observation has now been developed into a rapid screen for predicting the potency of products that show anti-inflammatory effect. Five-plants were screened by using this method. Among them, BuOH-fraction of Mucuna birdwoodiana showed strong inhibitory effect on $3{\alpha}-HSD$, and three isoflavone compounds were isolated. Inhibitory activates of isolated compounds were compared.

• Preventive Nutrition and Food Science
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• 제14권1호
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• pp.8-13
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• 2009

This study investigated the hypoglycemic effect of fermented soymilk extract (FSE) in STZ-induced diabetic mice. FSE was prepared via fermentation of soymilk with Bacillus subtilis followed by methanol extraction. The hypoglycemic effect was determined by inhibitory activities against ${\alpha}$-glucosidase and ${\alpha}$-amylase as well as the alleviation of postprandial glucose level. The non-fermented soymilk extract (SE) was used as control in this experiment. FSE showed higher (p<0.05) inhibitory activities than SE against ${\alpha}$-glucosidase and ${\alpha}$-amylase. The $IC_{50}$ values of FSE for ${\alpha}$-glucosidase and ${\alpha}$-amylase were 0.77 ancd 0.94 mg/mL, respectively, which were comparable or even superior to those of acarbose (0.79 and 0.68 mg/mL, respectively). In addition, a further suppression on the postprandial blood glucose levels were observed in the FSE than SE group for both STZ-induced diabetic mice and normal mice. Furthermore, FSE significantly lowered the incremental area under the curve (AUC) in the diabetic mice and the AUC in normal mice corroborated the hypoglycemic effect of FSE (p<0.05). Results from this study suggest that FSE may help decrease the postprandial blood glucose level via inhibiting ${\alpha}$-glucosidase and ${\alpha}$-amylase and the usefulness of FSE was proven to be better than SE.

• 한국식품과학회지
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• 제35권2호
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• pp.286-290
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• 2003

싸리버섯 메탄올 추출물의 항산화 효능을 DPPH법에 의한 free radical 소거작용능 및 $B({\alpha})P$로 간 독성이 유발된 마우스에서 항산화 효소, 글루타치온 및 과산화지질 함량 변화에 미치는 영향을 살펴보았다. 먼저 싸리버섯 메탄올 추출물의 항산화능을 DPPH radical 소거 작용법으로 시험한 결과 싸리버섯 추출물은 강한 자유라디칼 소거 효과를 나타내었다. 또한 $B({\alpha})P$투여로 인한 간 조직중의 SOD, catalase 그리고 GSH-Px의 활성은 유의적으로 증가되었다가, 싸리버섯 메탄올 추출물의 전 처리로 이들 활성이 유의적으로 감소하였다. 반면, GST 활성과 간 조직중의 글루타치온 함량은 $B({\alpha})P$ 단독군에서는 감소되었다가 싸리버섯 메탄올 추출물 투여시 유의적인 증가를 보였다. 그러나 지질과산화물 함량은 $B({\alpha})P$ 투여시 증가되었다가 싸리버섯 메탄올 추출물의 투여시 유의적으로 감소되었다. 이상의 결과로 싸리버섯 메탄올 추출물은 항산화계 효소의 활성 증가로 인한 $B({\alpha})P$에 의한 간 손상에 대한 보호효과를 가지는 것으로 사료된다.

• 생약학회지
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• 제31권2호
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• pp.196-202
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• 2000

This study was conducted to search for the ${\alpha}-glucosidase$ inhibitor from the natural products. In the previous study, the water extract of Gyrophora esculenta exhibited a potent inhibitory effect on ${\alpha}-glucosidase$ activities. Then, by bioassay-guided fractionation followed by chromatographic separation of the water extract of Gyrophora esculenta, ${\alpha}-glucosidase$ inhibitor was isolated as GE974. GE974 showed significant inhibitory activities on some kinds of ${\alpha}-glucosidase$ in vitro. Its inhibitory mechanism seemed to be competitive for disaccharides. Also, it markedly inhibited ${\alpha}-glucosidases$ of intestine separated from both nondiabetics and diabetics.

• 약학회지
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• 제32권2호
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• pp.129-136
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• 1988

Effects of the selective alpha-adrenoceptor agonists, clonidine, oxymetazoline and phenylephrine, on heart rate and contractile force were investigated in the isolated frog atria and it was attempted to examine the influence of adrenoceptor antagonist upon those. Clonidine produced dose-dependent negative chronotropic and positive inotropic effects. The negative chronotropic effect was significantly attenuated in the presence of prazosin and yohimbine but not propranolol. The positive inotropic effect was significantly attenuated by prazosin, yohimbine and propranolol. Oxymetazoline produced dose-dependent negative chronotropic and inotropic effects. The negative chronotropic effect was significantly attenuated in the presence of prazosin, which was partially augmented by yohimbine but was not affected by propranolol. The negative inotropic effect was not affected by propranolol but it was partially augmented by yohimbine and was partially attenuated by prazosin. Phenylephrine produced dose-dependent positive chronotropic and inotropic effects. The positive chronotropic and inotropic effect were significantly attenuated in the presence of propranolol but were not affected by prazosin and yohimbine. These results suggest that the negative chronotropic effect by clonidine and oxymetazoline is mediated by alpha-adrenoceptors, the positive chronotropic and inotropic effects by phenylephrine are mediated by beta-adrenoceptors, and alpha-adrenoceptors mediated the inhibitory chronotropic responses exists in the isolated frog atria.

• Bulletin of the Korean Chemical Society
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• 제25권1호
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• pp.42-44
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• 2004

Valerophenones containing a substituent at alpha position to the carbonyl group show the remarkable substituent effects on their photochemical reactions. ${\alpha}$-Bromovalerophenone gives only the C-Br bond cleavage products, but the ${\alpha}$-chlorovalerophenone follows the classical Norrish/Yang reaction pathway predominantly.

• 고려인삼학회:학술대회논문집
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• 고려인삼학회 2002년도 학술대회지
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• pp.66-83
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• 2002

Recently, we have provided evidence that ginsenosides, the active components of Panax ginseng, utilize pertussis toxin (PTX)-insensitive $G{\alpha}_{q/11}-phospholipase\;C-{\beta}3(PLC-{\beta}3)$ signal transduction pathway for the enhancement of $Ca^{2+}-activated\;Cl^{-}$ current in the Xenopus oocyte (British J. Pharmacol. 132, 641-647, 2001; JBC 276, 48797-48802, 2001). Other investigators have shown that stimulation of receptors linked to $G{\alpha}-PLC$ pathway inhibits the activity of G proteincoupled inwardly rectifying $K^+$ (GIRK) channel. In the present study, we sought to determine whether ginsenosides influenced the activity of GIRK 1 and GIRK 4 (GIRK 1/4) channels expressed in the Xenopus oocyte, and if so, the underlying signal transduction mechanism. In oocyte injected with GIRK 1/4 channel cRNAs, bath-applied ginsenosides inhibited high potassium (HK) solution-elicited GIRK current $(EC_{50}:4.9{\pm}4.3\;{\mu}g/ml).$ Pretreatment of the oocyte with PTX reduced the HK solution-elicited GIRK current by $49\%,$ but it did not alter the inhibitory ginsenoside effect on GIRK current. Prior intraoocyte injection of cRNA(s) coding $G{\alpha}_q,\;G{\alpha}_{11}\;or\;G{\alpha}_q/G{\alpha}_{11},\;but\;not\;G{\alpha}_{i2}\;or\;G{\alpha}_{oA}$ attenuated the inhibitory ginsenoside effect. Injection of cRNAs coding $G{\beta}_{1{\gamma}2}$ also attenuated the ginsenoside effect. Similarly, injection of the cRNAs coding regulators of G protein signaling 1, 2 and 4 (RGS1, RGS2 and RGS4), which interact with $G{\alpha}_i\;and/or\;G{\alpha}_{q/11}$ and stimulates the hydrolysis of GTP to GDP in active GTP-bound $G{\alpha}$ subunit, resulted in a significant reduction of ginsenoside effect on GIRK current. Preincubation of GIRK channel-expressing oocyte in PLC inhibitor (U73122) or protein kinase C (PKC) inhibitor (staurosporine or chelerythrine) blocked the inhibitory ginsenoside effect on GIRK current. On the other hand, intraoocyte injection of BAPTA, a free $Ca^{2+}$ chelator, had no significant effect on the ginsenoside action. Taken together, these results suggest that ginsenosides inhibit the activity of GIRK 1/4 channel expressed in the Xenopus oocyte through a PTX-insensitive and $G{\alpha}_{q/11}$-,PLC-and PKC-mediated signal transduction pathway.

• International Journal of Oral Biology
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• 제43권1호
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• pp.29-35
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• 2018

It is noted that chalcone derivatives have characteristic diverse pharmacological properties, and that precise evidence has been growing that they could regulate a tumor necrosis $factor-{\alpha}$ ($TNF-{\alpha}$) induced insulin resistance. The purpose of the present investigation is to elucidate the effects of the identified chalcone derivatives on adipogenesis, and to find the underlying mechanism of action in that case. Consequently, we first investigated whether the chalcone derivatives could affect the identified $PPAR{\gamma}$-induced transcriptional activity on the proliferator-activated receptor response elements (PPRE) at target promoters, and find that trans-chalcone most significantly increased the $PPAR{\gamma}$-induced transcriptional activity. Additionally, we confirmed that there were up-regulatory effects of trans-chalcone during the adipogenesis and lipid accumulation, and on the mRNA of adipogenic factors in 3T3-L1 cells. Next, we examined the effect of trans-chalcone on the inhibition induced by $TNF-{\alpha}$ on adipogenesis. To that end, we noted that the treatment with trans-chalcone attenuated the effect of $TNF-{\alpha}$ mediated secretion of various adipokines that are involved in insulin sensitivity. For this reason, we noted that this study clearly demonstrates that trans-chalcone enhanced adipogenesis, in part, by its potent effect on $PPAR{\gamma}$ activation and by its reverse effect on $TNF-{\alpha}$.