• 대한골관절종양학회지
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• 제3권1호
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• pp.9-17
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• 1997

Resistance to combination chemotherapy remains challenge in the treatment of osteosarcoma. One of the mechanisms of multiple drug resistance is an increased expression of the multidrug resistance gene(mdr1). Expression of the P-glycoprotein(mdr-1 gene product) was studied immunohistochemically and the mdr-1 gene by in situ hybridization in 33 osteosarcomas relating to various prognostic factors. Thirty cases out of 33 osteosarcomas(90.9%) showed positive cytoplasmic reactions with P-glycoprotein and nineteen instances(57.6%) were strong positive(2+). The older(>20 years) and female patients revealed more intense immunohistochemical reactions rather than those of the younger and male patients. Osteoblastic and chondroblastic osteosarcomas revealed more strong immunohistochemical reactions compared to fibroblastic types. There were no significant staining differences between the type of bony involvement, Broder's grade and the presence of necrosis. On follow-up, the mean survival rate was decreased in the strong positive group, however, this was not statistically significant. In situ hybridization for mdr-1 gene revealed positive signals in 22 cases out of 29 osteosarcomas(75.9%). Chemotherapy was done in 15 cases out of 28 patients(53.6%). The results of immunohistochemistry and in situ hybridization were not correlated with the protocols for chemotherapy. However, this result should be confirmed by a larger scale study about mdr1 mRNA expression.

• Journal of Ginseng Research
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• 제40권4호
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• pp.375-381
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• 2016

Background: We evaluated the drug interaction profile of Red Ginseng (RG) with respect to the activities of major cytochrome P450 (CYP) enzymes and the drug transporter P-glycoprotein (P-gp) in healthy Korean volunteers. Methods: This article describes an open-label, crossover study. CYP probe cocktail drugs, caffeine, losartan, dextromethorphan, omeprazole, midazolam, and fexofenadine were administered before and after RG supplementation for 2 wk. Plasma samples were collected, and tolerability was assessed. Pharmacokinetic parameters were calculated, and 90% confidence intervals (CIs) of the geometric mean ratios of the parameters were determined from logarithmically transformed data using analysis of variance after RG administration versus before RG administration. Results: Fourteen healthy male participants were evaluated, none of whom were genetically defined as poor CYP2C9, 2C19, and CYP2D6 metabolizers based on genotyping. Before and after RG administration, the geometric least-square mean metabolic ratio (90% CI) was 0.870 (0.805-0.940) for caffeine to paraxanthine (CYP1A2), 0.871 (0.800-0.947) for losartan (CYP2C9) to EXP3174, 1.027 (0.938-1.123) for omeprazole (CYP2C19) to 5-hydroxyomeprazole, 1.373 (0.864-2.180) for dextromethorphan to dextrorphan (CYP2D6), and 0.824 (0.658-1.032) for midazolam (CYP3A4) to 1-hydroxymidazolam. The geometric mean ratio of the area under the curve of the last sampling time ($AUC_{last}$) for fexofenadine (P-gp) was 0.963 (0.845-1.098). Administration of concentrated RG for 2 wk weakly inhibited CYP2C9 and CYP3A4 and weakly induced CYP2D6. However, no clinically significant drug interactions were observed between RG and CYP and P-gp probe substrates. Conclusion: RG has no relevant potential to cause CYP enzyme- or P-gp-related interactions.

• Bulletin of the Korean Chemical Society
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• 제33권4호
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• pp.1123-1127
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• 2012

P-gp (P-glycoprotein) is a member of the ATP binding cassette (ABC) family of transporters. It transports many kinds of anticancer drugs out of the cell. It plays a major role as a cause of multidrug resistance (MDR). MDR function may be a cause of the failure of chemotherapy in cancer and influence pharmacokinetic properties of many drugs. Hence classification of candidate drugs as substrates or nonsubstrate of the P-gp is important in drug development. Therefore to identify whether a compound is a P-gp substrate or not, in silico method is promising. Recursive Partitioning (RP) method was explored for prediction of P-gp substrate. A set of 261 compounds, including 146 substrates and 115 nonsubstrates of P-gp, was used to training and validation. Using molecular descriptors that we can interpret their own meaning, we have established two models for prediction of P-gp substrates. In the first model, we chose only 6 descriptors which have simple physical meaning. In the training set, the overall predictability of our model is 78.95%. In case of test set, overall predictability is 69.23%. Second model with 2D and 3D descriptors shows a little better predictability (overall predictability of training set is 79.29%, test set is 79.37%), the second model with 2D and 3D descriptors shows better discriminating power than first model with only 2D descriptors. This approach will be used to reduce the number of compounds required to be run in the P-gp efflux assay.

• 한국축산식품학회지
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• 제36권4호
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• pp.452-457
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• 2016

Lactoferrin is a glycoprotein with various biological effects, with antibacterial activity being one of the first effects reported. This glycoprotein suppresses bacterial growth through bacteriostatic or bactericidal action. It also stimulates the growth of certain kinds of bacteria such as lactic acid bacteria and bifidobacteria. In this study, Asn-Leu-Asn-Arg was selected and chemically synthesized based on the partial sequences of bovine lactoferrin tryptic fragments. Synthetic Asn-Leu-Asn-Arg suppressed the growth of Pseudomonas fluorescens, P. syringae and Escherichia coli. P. fluorescens is a major psychrotrophic bacteria found in raw and pasteurized milk, which decreases milk quality. P. syringae is a harmful infectious bacterium that damages plants. However, synthetic Asn-Leu-Asn-Arg did not inhibit the growth of Lactobacillus acidophilus. It is expected that this synthetic peptide would be the first peptide sequence from the bovine lactoferrin C-lobe that shows antibacterial activity.

• Archives of Pharmacal Research
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• 제28권7호
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• pp.823-828
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• 2005

Multidrug resistance (MDR) is one of the most significant obstacles in cancer chemotherapy. One of the mechanisms involved in the development of MDR is the over-expression of P-glycoprotein (P-gp). It is widely known that natural compounds found in vegetables, fruits, plant-derived beverages and herbal dietary supplements not only have anticancer properties, but may also modulate P-gp activity. Therefore, the purpose of this investigation was to examine the effects of naturally occurring products on P-gp function in human breast cancer cell lines, MCF-7 (sensitive) and MCF-7/ADR (resistant). The accumulation of daunomycin (DNM), a P-gp substrate, was greater in the sensitive cells compared to the resistant cells, while the efflux of DNM was higher in the resistant cells compared to the sensitive cells over a period of 2h. The $IC_{50}$ value of DNM in the resistant cells was about 22 times higher than that in the sensitive cells, indicating an over-expression of P-gp in the resistant cells, MCF-7/ADR. All of the compounds tested, with the exception of fisetin, significantly decreased the $IC_{50}$ value of DNM. Biochanin A showed the greatest increase in $[^3H]-DNM$ accumulation, increasing by $454.3{\pm}19.5%$ in the resistant cells, whereas verapamil, the positive control, increased the accumulation by $229.4{\pm}17.6%$. Also, the accumulation of $[^3H]-DNM$ was increased substantially by quercetin and silymarin while it was reduced by fisetin. Moreover, biochanin A, silymarin, and naringenin significantly decreased DNM efflux from MCF-7/ADR cells compared with the control. These results suggest that some flavonoids such as biochanin A and silymarin may reverse MDR by inhibiting the P-gp function.

• Journal of Korean Neurosurgical Society
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• 제41권6호
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• pp.397-402
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• 2007

Objective : Balloon cells and dysplastic neurons are histopathological hallmarks of the cortical tubers of tuberous sclerosis complex [TSC] and focal cortical dysplasia [FCD] of the Taylor type. They are believed to be the epileptogenic substrate and cause therapeutic drug resistant epilepsy in man. P-glycoprotein [P-gp] is the product of multidrug resistance gene [MDR1], and it maintains intracellular drug concentration at a relatively low level. The authors investigated expression of P-gp in balloon cells and dysplastic neurons of cortical tubers in patients with TSC. Methods : An immunohistochemical study using the primary antibody for P-gp, as an indicative of drug resistance, was performed in the cortical tuber tissues in two patients of surgical resection for epilepsy and six autopsy cases. Results : Balloon cells of each lesion showed different intensity and number in P-gp immunopositivity. P-gp immunopositivity in balloon cells were 28.2%, and dysplastic neurons were 22.7%. These immunoreactivities were more prominent in balloon cells distributed in the subpial region than deeper region of the cortical tubers. Capillary endothelial cells within the cortical tubers also showed P-gp immunopositivity. Conclusion : In this study, the drug resistance protein P-glycoprotein in balloon cells and dysplastic neurons might explain medically refractory epilepsy in TSC.

• Journal of Pharmaceutical Investigation
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• 제33권4호
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• pp.305-310
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• 2003

One of the possible mechanisms of multi-drug resistance found in cancer cells is the over-expression of P­glycoprotein (P-gp). Studies have shown that compounds in plants including vegetables and fruits not only have anticancer activities but may also modulate P-gp activity. The effect of flavonoids and organic isothiocyanate on P-gp activity was studied in human uterine sarcoma cell lines, MES-SA (sensitive) and MES-SA/DX5 (resistant) cells. The accumulation of daunomycin (DNM), a P-gp substrate, was approximately 10 times greater in the sensitive cell as compared to the resistant cells over the entire time course (up to 2 hours). The positive control, verapamil increased the two hour accumulation of DNM while quercetin decreased that of DNM in the resistant cells. 1-Naphtyl-isothiocyanate (NITC) showed no effect on the two hour accumulation of DNM. The $IC_{50}$ values for DNM in the resistant cells was about 20 times higher than that observed in the sensitive cells $(10.1{\pm}1.7\;{\mu}M\;vs.\;0.58{\pm}0.28\;{\mu}M)$. Verapamil reduced the $IC_{50}$ value for DNM whereas flavonoids (quercetin and fisetin) increased those for DNM in the resistant cells.

• 약학회지
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• 제54권4호
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• pp.252-257
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• 2010

The aim of this study was to investigate the effect of resveratrol on the pharmacokinetics of nifedipine in rats. The pharmacokinetic parameters of nifedipine were measured after the oral administration of nifenipine (6 mg/kg) in the presence or absence of resveratrol (0.5, 2.5 and 10 mg/kg, respectively). The effect of resveratrol on the P-glycoprotein (Pgp), CYP 3A4 activity was also evaluated. Resveratrol inhibited CYP3A4 enzyme activity in a concentration-dependent manner with 50% inhibition concentration ($IC_{50}$) of 0.94 ${\mu}M$. In addition, resveratrol significantly enhanced the cellular accumulation of rhodamine 123 in MCF-7/ADR cells overexpressing P-gp. Compared to the control groups, the presence of 2.5 mg/kg and 10 mg/kg of resveratrol significantly (p<0.05, p<0.01) increased the area under the plasma concentrationtime curve (AUC) of nifedipine by 49~75%, and the peak concentration ($C_{max}$) of nifedipine by 48~66%. The absolute bioavailability (AB%) of nifedipine was significantly (p<0.05) increased by 22.9-34.8% compared to the control (19.8%). The terminal half-life ($T_{1/2}$) of nifedipine was significantly (p<0.05) increased compared to the control. While there was no significant change in the time to reach the peak plasma concentration ($T_{max}$) of nifedipine in the presence of resveratrol. It might be suggested that resveratrol altered disposition of nifedipine by inhibition of both the CYP3A and P-glycoprotein efflux pump in the small intestine of rats. In conclusion, the presence of resveratrol significantly enhanced the oral bioavailability of nifedipine, suggesting that concurrent use of resveratrol or resveratrol-containing dietary supplenment with nifedipine should require close monitoring for potential drug interation.

• 한국식품영양과학회지
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• 제25권2호
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• pp.240-248
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• 1996

육상생물에 비해 활성물질의 급원으로서 이용율이 낮은 해양생물자원인 해삼(홍삼, 청삼 및 흑삼)에서 당단백질을 추출하여 그 화학성분의 조성을 규명하고 이들의 물리화학적 특성과 식이효과를 실험하였다. 일반 성분의 함량은 종류에 따라 큰 차이가 없으며, 특히 점질다당체의 주성분인 chondrotin sulfate의 함량이 2.6~3.2%를 함유하고 있다. 동결건조해삼분말에서 추출한 당단백질의 유화성과 유화안정성은 동결건조해삼분말 보다 각각 56~77%, 33~71%로 증가하였다. 당단백질은 보수력을 측정하기에 곤란할 정도로 증류수에서의 용해도가 높았으며, 동결건조해삼분말의 보수력은 913.4%(홍삼), 673.5%(청삼) 및 870.4%(흑삼)로 나타났다. 점도는 홍삼으로부터 분리한 당단백질의 점도가 제일 높았으며 청삼과 흑삼은 유사하였다. 해삼에서 분리한 당단백질의 구성아미노산은 홍삼이 청삼 및 흑삼에 비해서 전체 단백질에 차지하는 구성아미노산의 비율이 높은 편이었으며(홍삼 96%, 청삼 91.6% 및 흑삼 88.2%), 각 당단백질의 Asx와 Glx는 모두 10%이상을 차지하였고, 특히 histidine이 2% 이하의 낮은 결과를 보였다. 동결건조분말에 비해 당단백질의 valine, phenylalanine 및 lysine의 함량은 모두 약 2배 증가하였는데 비해 glycine은 약 60~70%, Arg은 약 40% 감소하였다. 동결조건해삼분말 중 청삼과 여기서 추출한 당단백질을 몇종의 단백질 식품(casein, 분유, 콩단백추출 및 오징어)에 여러 가지 비율로 첨가시켜 소화율의 저해효과를 보았을 때 casein, 분유, 콩단백질추출물의 소화율이 3.5~6%와 4.5~11.4%의 저해효과를 보았으나 오징어 단백질에 대해서는 모두 큰 저해효과가 없었다.

• 한국식품과학회지
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• 제41권1호
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• pp.93-99
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• 2009

꾸지뽕 당단백질이 간의 조직에 존재하는 항산화계 해독효소의 활성을 증가시켜서 $CCl_4$로 유도된 간독성화 과정에서 생성된 ROS에 의해 야기되는 산화적 스트레스를 억제하는 scavenger로서 기능을 가지고 있는 것으로 분석된다. 또한 혈청 중 LDH 활성증가는 간 및 기타조직의 질환 및 악성 종양 등에서 나타나는 소견으로 LDH를 내포한 조직이 파괴될 때 혈액으로 흘러나와 혈중 LDH가 상승하며, 혈액 중 지질과산화 반응은 생체조직막의 다가불포화지방산 유리기에 의해 산화적 분해를 일으키는 지표로 사용되는 TBARS의 수치, DNA 염기의 deamination 등을 유도함으로써, 유전자의 돌연변이(mutagenesis)로 인한 세포독성을 일으키는 NO 등의 수치가 유의적인 수준으로 억제될 뿐만 아니라, 염증 매개시 단백질인 NF-kB(p50)을 억제함으로써 $CCl_4$에 의한 간독성 과정에서 촉진된 염증 신호전달기전을 억제할 수 있었다. 따라서 꾸지뽕 당단백질은 탁월한 천연 항산화제로서 간의 독성 및 염증 반응을 억제하는 것으로 실험결과 분석된다.