• Genomics & Informatics
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• 제19권1호
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• pp.7.1-7.13
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• 2021

Levodopa (L-DOPA) therapy is normally practised to treat motor pattern associated with Parkinson disease (PD). Additionally, several inhibitory drugs such as Entacapone and Opicapone are also cosupplemented to protect peripheral inactivation of exogenous L-DOPA (~80%) that occurs due to metabolic activity of the enzyme catechol-O-methyltransferase (COMT). Although, both Entacapone and Opicapone have U.S. Food and Drug Administration approval but regular use of these drugs is associated with high risk of side effects. Thus, authors have focused on in silico discovery of phytochemicals and evaluation of their effectiveness against human soluble COMT using virtual screening, molecular docking, drug-like property prediction, generation of pharmacophoric property, and molecular dynamics simulation. Overall, study proposed, nine phytochemicals (withaphysalin D, withaphysalin N, withaferin A, withacnistin, withaphysalin C, withaphysalin O, withanolide B, withasomnine, and withaphysalin F) of plant Withania somnifera have strong binding efficiency against human COMT in comparison to both of the drugs i.e., Opicapone and Entacapone, thus may be used as putative bioenhancer in L-DOPA therapy. The present study needs further experimental validation to be used as an adjuvant in PD treatment.

• Natural Product Sciences
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• 제22권3호
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• pp.187-192
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• 2016

The goal of this study was to determine whether gypenosides (GPS) exert protective effects against dopaminergic neuronal cell death in a 6-hydroxydopamine (OHDA)-lesioned rat model of Parkinson's disease (PD) with or without long-term 3,4-dihydroxyphenylalanine (L-DOPA) treatment. Rats were injected with 6-OHDA in the substantia nigra to induce PD-like symptoms; 14 days after injection, groups of 6-OHDA-lesioned animals were treated for 21 days with GPS (25 or 50 mg/kg) and/or L-DOPA (20 mg/kg). Dopaminergic neuronal cell death was assessed by counting tyrosine hydroxylase (TH)-immunopositive cells in the substantia nigra and measuring levels of dopamine, norepinephrine, 3,4-dihydroxyphenylacetic acid (DOPAC), and homovanillic acid (HVA) in the striatum. Dopaminergic neuronal cell death induced by 6-OHDA lesions was ameliorated by GPS treatment (50 mg/kg). L-DOPA treatment exacerbated 6-OHDA-induced dopaminergic neuronal cell death; however, these effects were partially reversed by GPS treatment (25 and 50 mg/kg). These results suggest that GPS treatment is protective against dopaminergic neuronal cell death in a 6-OHDA-lesioned rat model of PD with long-term L-DOPA treatment. Therefore, GPS may be useful as a phytotherapeutic agent for the treatment of PD.

• Biomolecules & Therapeutics
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• 제13권1호
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• pp.32-34
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• 2005

Effect of isoliquiritigenin isolated from the heartwood of Dalbergia odorifera T. Chen (Leguminosae) on mushroom tyrosinase activity was investigated in vitro using L-tyrosine and L-3, 4-dihydroxyphenylalanine (L-DOPA) as the substrates. When L-tyrosine was used as a substrate, both isoliquiritigenin and kojic acid, a positive control, inhibited tyrosinase activity in a concentration-dependent manner. IC$_{50}$ values of isoliquiritigenin and kojic acid were 61.4 and 52.2 ${\muM}$, respectively. However, isoliquiritigenin showed week inhibitory effect on the oxidation of L-DOPA by tyrosinase with inhibition ratio of 9.1 ${\pm}$ 7.1% at 100 ${\muM}$. It is also suggested that 3-unsubstituted and 4-hydroxyl phenyl group in isoliquiritigenin plays an important role on the inhibition of tyrosinase activity when L-tyrosine was used as a substrate. Analysis of Lineweaver-Burk plot showed that isoliquiritigenin acts as a competitive inhibitor in case of L-tyrosine as a substrate.

• 약학회지
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• 제49권2호
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• pp.156-161
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• 2005

Tetrahydropapaveroline (THP) at 5-15 ${\mu}$M has been found to induce L-DOPA-induced oxidative apoptosis in PC12 cells. In this study, the inhibitory effects of THP on dopamine bios ynthesis in PC12 cells and tyrosine hydroxylase (TH) activity in bovine adrenal were investigated. Treatment of PC12 cells with THP at 2.5-10 ${\mu}$M significantly decreased the intracellular dopamine content in a concentration-dependent manner (18.3% inhibition at 10 ${\mu}$M THP). In these conditions, TH activity was markedly inhibited by the treatment with THP at 2.5-10 ${\mu}$M in PC12 cells (23.4% inhibition at 10 $\mu$ M THP). In addition, THP had an inhibitory effect on bovine adrenal TH activity IC50 value, 153.9${\mu}$M). THP exhibited uncompetitive inhibition on bovine adrenal TH activity with a substrate L-tyrosine with the KI value of 0.30 mM. Treatment with L-DOPA at 20~50 ${\mu}$M increased the intracellular dopamine content in PC12 cells, and the increase in dopamine content by L-DOPA was inhibited in part when THP at non-cytotoxic (5-10 ${\mu}$M) or cytotoxic (15${\mu}$M) concentrations was associated with L-DOPA (20 and 50 ${\mu}$M) for 24 h incubation. These results suggest that THP at 5-10${\mu}$M decreases the basal dopamine content and reduces the increased dopamine content induced by L-DOPA in part by the inhibition of TH activity, and that THP at 15${\mu}$M also decreases dopamine content by oxidative stress in PC12 cells.

• 대한화장품학회지
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• 제31권2호
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• pp.153-159
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• 2005

본 연구는 한방제제의 구성 약재인 마황이라는 천연한방소재로부터 미백효과가 있는 화장품 원료를 개발하고자 하였다. 본 실험에서 마황추출물의 tyrosinase 억제 효과를 확인하고 마황추출 과정을 세분화하여 methylene chloride 및 물분획물을 얻었으며 이들을 가지고 다시 tyrosinase 억제 실험을 실시하였다. 그 결과 수층부분에서만 $0.2\%$ 농도에서 $60.6\%$의 tyrosinase 억제 효과를 보여주었으며 이후 수층부분만을 농축하여 L-DOPA 산화억제 실험 및 B-16 melanoma를 이용한 미백 실험을 실시하였다. 그 결과 마황추출물 $0.5\%$ 농도에서 $87\%$의 L-DOPA 산화억제 효과를 보여주었으며, $0.75\%$에서는 $98.8\%$의 억제효과를 보여주었다. 또한 B-16 melanoma에서는 $0.05\%$에서 $70.2\%$, $0.075\%$에서는 $79.9\%$의 억제효과를 보여주었다. 그리고 수층부분만을 농축한 마황추출물의 in vivo상에서의 미백 효과를 검증하기 위하여 마황추출물 $0.5\%$를 함유한 제형으로 미백 임상실험을 실시하였다. 그 결과 마황추출물을 함유한 제형에서 10주 경과 후에 육안 및 기기평가 모두에서 미백효과를 보여주었으며 통계적으로도 유의한 차이(p<0.05)를 보여주었다.

• Bulletin of the Korean Chemical Society
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• 제26권7호
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• pp.1135-1137
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• 2005

• 한국자원식물학회지
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• 제14권1호
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• pp.32-37
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• 2001

한약재 174종으로부터 tyrosinase 저해제를 탐색하였다. 한약재는 30일간 methanol에 담가 놓은 후, 그 추출액을 제조하여 사용하였다 Tyrosinase의 활성을 측정하기 위해서는 효소 mushroom Tyrosinase와 기질 L-DOPA, phosphate buffer를 사용하였다. 탐색 결과, 한약재 174종 중 14개종이 tyrosinase를 저해 효과를 보였고, 그중 오배자 추출액이 inhibition activity가 가장 높게 나타났다.

• 대한핵의학회지
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• 제19권2호
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• pp.69-79
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• 1985

To evaluate the effect of dopaminergic activity on aldosterone secretion, the plasma renin activity, serum cortisol and aldosterone were measured by radioimmunoassay in 6 normal controls and 12 patients who had hyponatremia and generalized edema or ascites with possible condition with secondary aldosteronism before and after(15, 30, and 60 min) 15 mg of metoclopramide by iv bolus injection and same method with 500 mg of L-dopa by per oral in 6 normal controls and 12 patients with edema ascites. The result were as follows; 1) The basal level of PRA was higher in patients rather than normal controls but PRA was not influenced by MC or L-dopa administration on both normal controls and patients group. 2) The serum cortisol level was significantly elevated at 30 min after MC injection compared with basal level in normal controls but no significant change was noted in patients group. After L-dopa administration the serum cortisol level was not changed in both normal controls and patients group. 3) The serum aldosterone level was significantly elevated in 15, 30 and 60 min after MC injection in normal controls, and there also same tendency of aldosterone secretion was noticed in patients group. On the other hands, there was no changes in aldosterone level in both normal controls and patients group with L-dopa administration. Above result means that MC stimulate aldosterone secretion by dopaminergic antagonist and aldosterone secretion in normal subject is controlled by maximal tonic dopaminergic inhibition. In edematous patients, however, both of the dopaminergic inhibitory and stimulating effect of PRA, ACTH etc on the aldosterone secretion seems to be variable.

• Biomolecules & Therapeutics
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• 제31권4호
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• pp.402-410
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• 2023

Long-term administration of levodopa (L-DOPA) to patients with Parkinson's disease (PD) commonly results in involuntary dyskinetic movements, as is known for L-DOPA-induced dyskinesia (LID). 5-Hydroxytryptophan (5-HTP) has recently been shown to alleviate LID; however, no biochemical alterations to aberrant excitatory conditions have been revealed yet. In the present study, we aimed to confirm its anti-dyskinetic effect and to discover the unknown molecular mechanisms of action of 5-HTP in LID. We made an LID-induced mouse model through chronic L-DOPA treatment to 6-hydroxydopamine-induced hemi-parkinsonian mice and then administered 5-HTP 60 mg/kg for 15 days orally to LID-induced mice. In addition, we performed behavioral tests and analyzed the histological alterations in the lesioned part of the striatum (ST). Our results showed that 5-HTP significantly suppressed all types of dyskinetic movements (axial, limb, orolingual and locomotive) and its effects were similar to those of amantadine, the only approved drug by Food and Drug Administration. Moreover, 5-HTP did not affect the efficacy of L-DOPA on PD motor manifestations. From a molecular perspective, 5-HTP treatment significantly decreased phosphorylated CREB and ΔFosB expression, commonly known as downstream factors, increased in LID conditions. Furthermore, we found that the effects of 5-HTP were not mediated by dopamine1 receptor (D1)/DARPP32/ERK signaling, but regulated by AKT/mTOR/S6K signaling, which showed different mechanisms with amantadine in the denervated ST. Taken together, 5-HTP alleviates LID by regulating the hyperactivated striatal AKT/mTOR/S6K and CREB/ΔFosB signaling.

• Bulletin of the Korean Chemical Society
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• 제32권3호
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• pp.977-980
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• 2011

A new analytical method for measurement of 3,4-dihydroxyphenylalanine (DOPA) in human urine was developed. DOPA from an aqueous solution was converted into an ethoxycarbonyl (EOC) derivative. A tertbutyldimethylsilyl (TBDMS) reaction under anhydrous conditions was then attempted for analysis by gas chromatography-mass spectrometry in selected ion monitoring mode. A new mass spectral data on DOPA as a tri-EOC/mono-TBDMS derivative was built. This method showed good linearity (r ${\geq}$ 0.999), precision (% relative standard deviation = 3.1-9.2), and accuracy (% relative error = -7.2-8.8), with a detection limit of 0.05 ng/mL. This selective and accurate method of DOPA analysis will be useful for biochemical monitoring of various neurological disorders including Parkinson's disease in biological fluids.