• 약학회지
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• 제52권6호
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• pp.426-433
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• 2008

The interaction of cadmium (II) ion with protocatechuic acid ($H_3PA$) and ethylenediaminetetraacetic acid (EDTA) were investigated in aqueous solution at different pH. The protocatechuic acid and EDTA/cadmium stochiometries for cadmium (II) binding have been determined by UV-vis spectrophotometric method. The complexation of Cd (II) ion with protocatechuic acid was formed in solution. Among the two potential sites of chelation present in the protocatechuic acid structure, the carboxylic function presents higher complexation power toward Cd (II). 1 : 1 Cd (II)-complex had a maximum absorbance and showed the bathochromic shift of the long-wavelength band of the UV-vis spectra in the alkaline pH when interacted with protocatechuic acid in 0.2 M $NH_3$ - 0.2 M ${NH_4}Cl$ (pH 8.0) buffer. These results suggest that Cd $({H_2}PA)^+$ complex has the optimal condition of chelation in buffer solution at 64.22 ${\mu}M$ protocatechuic acid (A=1.01455).

• 약학회지
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• 제54권1호
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• pp.13-21
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• 2010

The interaction of cadmium (II) ion with quercetin, qurecitrin and (+)-catechin was investigated in aqueous solution at various pH. The flavonoid/cadmium stochiometries for cadmium (II) binding to flavonoid have been determined by UV-visible spectroscopy. 1:1 Cd(II)-Flavonoid complex had a maximum absorbance and showed the bathochromic shift of the long-wavelength band of the UV-vis spectra in the alkaline pH, that occurs upon complexation, is due to a ligand-tometal charge transfer. The optimal concentration of Cd(II)-flavonoid complexes showed that complexation reaction could be classified in the following way: 55.27 ${\mu}M$ catechin > 54.72 ${\mu}M$ quercetin > 53.52 ${\mu}M$ quercitrin at the chelating site level. These results suggest that Cd(II)-flavonoid complex has the optimal condition of chelation in 0.2 M $NH_3$ - 0.2 M $NH_4Cl$ (pH 8.0) solution.

• 대한약침학회지
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• 제20권4호
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• pp.265-273
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• 2017

Objective: Orthosiphon pallidus (O. pallidus), which belongs to the Lamiaceae family, is a popular garden plant that is widely used for the treatment of various diseases, such as urinary lithiasis, fever, hepatitis, cancer and jaundice. The objective of the present work was to investigate the antioxidant free-radical scavenging and the anticancer activities of O. pallidus against human breast-cancer cell lines. Methods: The antioxidant activity of Orthosiphon pallidus aqueous extract (OPAE) was investigated using different models, such as the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and the 2, 2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) models, as were the $Fe^+$ chelation, the hydroxyl radical and superoxide radical scavenging, and total reducing power activities. The anticancer activities of the extract were determined by using the 3-(4, 5- dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide (MTT) and the sulforhodamine (SRB) assays on the MCF-7 and the MDA-MB-231 cancer cell lines. Results: The aqueous Orthosiphon pallidus extract showed potent activity in in-vitro models. It significantly inhibited the scavenging of hydroxyl and superoxide radicals, but induced a remarkable $Fe^+$ chelation activity. For both cell lines, the percent cytotoxicity was found to increase steadily with increasing OPAE concentration up to $240{\mu}g/mL$. Conclusion: These results suggest that Orthosiphon pallidus has excellent antioxidant, antimicrobial, and anticancer activities against human breast-cancer cell lines.

• Toxicological Research
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• 제33권4호
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• pp.299-304
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• 2017

Thallium and its compounds are a class of highly toxic chemicals that cause wide-ranging symptoms such as gastrointestinal disturbances; polyneuritis; encephalopathy; tachycardia; skin eruptions; hepatic, renal, cardiac, and neurological toxicities; and have mutagenic and genotoxic effects. The present research aimed to evaluate the efficacy of the chelating agents deferasirox (DFX) and deferiprone (L1) in reducing serum and tissue thallium levels after the administration of thallium (III), according to two different dosing regimens, to several groups of Wistar rats for 60 days. It was hypothesized that the two chelators might be more efficient as a combined therapy than as monotherapies in removing thallium (III) from the rats' organs. The chelators were administered orally as either single or combined therapies for a period of 14 days. Serum and tissue thallium (III) and iron concentrations were determined by flame atomic absorption spectroscopy. Serum and tissue thallium (III) levels were significantly reduced by combined therapy with DFX and L1. Additionally, iron concentrations returned to normal levels and symptoms of toxicity decreased.

• Bulletin of the Korean Chemical Society
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• 제28권10호
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• pp.1645-1650
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• 2007

This paper describes a racemic and stereoselective synthetic route for a novel cyclohexenyl carbocyclic adenine analogue. The required stereochemistry of the target compound was controlled using a stereoselective glycolate Claisen rearrangement followed by α-chelated carbonyl addition. The introduction of 6-chloropurine was achieved using Mitsunobu conditions, and further modifications of the corresponding heterocycle gave the target cyclohexenyl nucleoside.

• 대한약학회:학술대회논문집
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• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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• pp.345.3-346
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• 2002

In connection with the asymmetric synthesis of chiral l.2-diol. we report here the total synthesis of (＋)-frontalin using diastereoselective alkylation featuring tridentate chelation-controlled asymmetric alkylation of a-hydroxyketone, in which the chiral auxiliary is attached to the hydroxyl group as ether linkage. The starting D-glyceraldehyde acetonide was converted (S)- ［(4R)-2.2-dimethyH,3-dioxolan-4-yl］ (4-methoxyphenyl) methanol. (omitted)

• 약학회지
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• 제13권1호
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• pp.22-27
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• 1969

Nicotinamide Complex Compound was not formed in simple alkaline solution under two to one molar ratio of dimethyglyoxime and Fe (II), but it was formed with ammonia or pyridine under the same molar ratio. Based on this fact, nicotinamide solution was added into dimethyglyoxime-Fe (II) complex solution, and the chelation product was extracted with chloroform. The extraction was Completed in a range of pH 8.4-11.0. The chloroform solution shows stability and maximum absorption at 516 m${\mu}$.

• Journal of the korean society of oceanography
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• 제34권1호
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• pp.49-57
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• 1999

A red tide organism, Amphidinium carterae was incubated under different iron/chelator and nitrate concentrations to investigate the factors controlling the growth. The chelation capacity played a critical role in regulating the nitrate reductase (NR) activity and in vivo fluorescence of this organism. However, there was a significant difference between the NR activity and in vivo fluorescence in response to trace metals and chelator treatments. In vivo fluorescence was the highest in FeEDTA 10 ${\mu}$M treatments and the lowest in DTPA 10 ${\mu}$M treatments. This indicates that the availability of the trace metal is important in regulating the in vivo fluorescence of this photosynthetic microalgae In contrast, NR activity showed the highest values in trace metal enriched treatments, and trace metal + DTPA treatments showed fairly high NR activities. This suggests that DTPA treatment did not hinder the NR activity as much as it did in vivo fluorescence. In vivo fluorescence and NR activity increased with nitrate concentration of up to 50 ${\mu}$M and remained relatively constant or the rate of increase decreased above that concentration, indicating that initial nitrate concentration of higher than a certain level would not accelerate the growth of A. carterae. Further investigation is needed to elucidate the reason for the difference in timing sequence between the NR and in vivo fluorescence in response to different metal treatments and chelation capacity.

• 한국식품과학회지
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• 제29권2호
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• pp.320-325
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• 1997

이소말토올리고당의 생산에 사용되는 Aspergillus niger 유래의 TG의 고정화를 위해 여러가지 방법을 비교하여 고정화방법을 선정하였다. 이온결합과 흡착, entrapment, 공유결합과 금속이온을 이용한 결합 등을 이용하여 TG의 고정화를 시도하였다. TG의 고정화를 위해서는 수율면에서 우수하고(61.3%) 간편성도 있는 CNBr-activated sepharose 4B를 이용한 고정화 방법을 선정하였다. DEAE-sephadex를 이용한 이온결합에 의해서는 33.1%, Diaion HP-20를 이용한 흡착법에 의해서는 22.5%의 수율을 보였으나 CNBr-activated sepharose 4B를 이용한 고정화 방법에 비해 수율과 안정성이 낮아 제외하였다. Entrapment에 의한 고정화는 bead내의 확산저항으로 인해 최종산물의 생성에 불리한 것으로 판단되었고 magnesium silicate, silica gel, glass bead 등의 담체를 이용한 고정화방법은 낮은 수율로 인해, 금속이온을 이용한 경우 역시 낮은 수율과 장시간의 준비로 인해 고정화방법으로 부적당하다고 판단되었다.

• Applied Biological Chemistry
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• 제46권1호
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• pp.7-11
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• 2003

감자 polyphenol oxidase의 구리결합지역 DNA와 histidine 다량 함유 인공 펩타이드를 암호화하는 DNA를 대장균 벡터에 각각 클로닝하여 발현시킨 후 대장균 내의 구리함량 증감을 조사하였다. Polyphenol oxidase의 구리결합지역 DNA를 포함하는 PPOCBpET32 벡터를 함유하는 균주의 경우는 벡터를 함유하지 않는 대장균 대조구보다 오히려 구리 함량이 약간 감소하여 약 600ppm의 간을 보여주어, 감자 polyphenol oxidase 구리결합지역의 대장균 내에서의 발현이 구리 함량 증가에 기여하지 못함을 알 수 있었다. 반면에 한 개의 hexahistidine 단위 DNA를 포함하는 pET28a 벡터 함유 대장균 균주를 knamycin 미첨가 배지에서 배양한 경우에는 구리 함량이 약 2,500ppm으로 높게 나타났다. 한편 hexahistidine 9개로 구성된 polyhistidine을 암호화하는 DNA를 포함하는 pET-his 벡터 함유 균주를 kanamycin 미첨가 배지에서 배양한 경우에 구리함량이 약 3,200ppm으로 나타나, 하나의 hexahistidine 단위만 발현하는 균주와 비교하여 구리함량이 약 30% 증가됨을 알 수 있었다.