• 대한본초학회지
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• 제33권4호
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• pp.95-100
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• 2018

Objectives : Ligustri Fructus has been used since ancient times as a medicinal usages in folk medicines against antitumor purpose. Many biological active constituents have been identified from this biomass such as several terpenoids and lignans. In current study, the properties of antioxidant and anti-diabetic complications using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)($ABTS^+$) radicals scavenging, and advanced glycation end products (AGEs) inhibition assays were evaluated by different extraction methods of Ligustri Fructus. Methods : In present continuing research for development of bioactive natural ingredients, antioxidant and AGEs formation inhibitory capacities of Ligustri Fructus extracts using different organic solvents were prepared and the biological potentials were investigated using in vitro bioassays. Antioxidant properties were evaluated employing radical scavenging assays using DPPH and $ABTS^+$ radicals. In addition, the anti-diabetic complications effects of Ligustri Fructus extracts were tested via AGEs formation inhibitory assay. The total phenolic contents were determined using a spectrophotometric method. Results : All the tested extracts exhibited dose-dependent radical scavenging and AGEs formation inhibitory activities. Among the tested samples, hot water extract of Ligustri Fructus was showed the most potent activity with $IC_{50}$ value of $494.8{\pm}6.7{\mu}g/m{\ell}$ against DPPH radical scavenging assay. Also, $ABTS^+$ radical scavenging activity of hot water extract was higher than those of other extracts. In addition, AGEs formation inhibitory effects of each extacts and total phenolic contents were evaluated. Conclusions : These results suggested that Ligustri Fructus can be considered as a new effective source of natural antioxidant and anti-diabetic complications resources.

• 대한본초학회지
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• 제32권6호
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• pp.1-7
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• 2017

Objectives : The heartwood of Sappan Lignum has been used since ancient times as an ingredient in folk medicines against anti-bacterial and anti-anemia purposes. Many bioactive constituents have been derived from this biomass such as chalcones and homoisoflavonoids. In the current investigation, the antioxidant and anti-diabetic properties using DPPH and $ABTS^+$ radicals scavenging, ${\alpha}-glucosidase$, and advanced glycation end products (AGEs) inhibition assays were evaluated by different extraction methods of Sappan Lignum. Methods : In our continuing investigation for bioactive natural ingredients, the antioxidant and ${\alpha}-glucosidase$ inhibitory properties of Sappan Lignum extracts were prepared from different extraction methods and the biological efficacies were investigated in vitro. The antioxidant properties were evaluated employing radical scavenging assays using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) ($ABTS^+$) radicals. In addition, the anti-diabetic effects of Sappan Lignum extracts were tested via ${\alpha}-glucosidase$ and AGEs formation inhibitory assay. The total phenolic contents were determined using a spectrophotometric method. Results : All the tested samples showed dose-dependent radical scavenging and ${\alpha}-glucosidase$ inhibitory activities. Among the tested extracts, the 80% methanolic extract of Sappan Lignum was showed the most potent activity with an $IC_{50}$ value of $82.3{\pm}1.7{\mu}g/m{\ell}$ against DPPH radical scavenging assay. While, $ABTS^+$ radical scavenging activity of 80% methanolic extract was higher than those of other extracts. Also, ${\alpha}-glucosidase$ inhibitory and AGEs formation effects of each extacts and total phenolic contents were evaluated. Conclusions : These results suggested that Sappan Lignum can be considered as a new effective source of natural antioxidant and anti-diabetic materials.

• 대한화학회지
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• 제39권2호
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• pp.87-93
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• 1995

크롬도금 용액에 공존하고 있는 Cr(III)와 Cr(VI)의 양을 자외선/가시광선 분광기에 장착한 흐름계 장치를 이용하여 시료당 5분 이내에 두 가지 물질의 양을 동시에 분석하는 방법을 개발하였다. Cr(III)와 Cr(VI)는 각각 580 nm와 440 nm에서 0.05 g/L와 0.005 g/L 이상의 범위에서 Beer-Lambert 법칙에 따르는 특성 ${\lambda}_{max}$를 나타내며, 이 파장들에서의 흡광도는 pH<4의 조건에서는 pH변화에 거의 영향을 받지 않았다. 따라서 일반적으로 크롬의 농도가 수 g/L인 후처리 크롬 도금조의 용액을 흐름계의 장치에서 pH=1의 황산 용액으로 묽힌 후, 자외선/가시광선 분광기로 측정하면 Cr(III)와 Cr(VI)의 양 및 총 크롬의 양을 기존의 산화-환원 적정 방법(최소 40분/sample)보다 간편하고 신속정확하게 동시 정량할 수 있었다. 이 장치는 설치 및 사용이 간단하고, 설치 비용이 저렴하므로 많은 도금 산업 현장에서 용이하게 응용할 수 있다.

• 대한화학회지
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• 제31권4호
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• pp.344-351
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• 1987

$[Mo_2O_4(H_2O)_6]^{2+}$와 티오시안산과의 착물생성에 대한 속도론적 연구는 분광광도법으로 수행하였다. 이 반응의 관찰된 속도상수 $k_{obsd}$는 다음과 같이 주어진다. $k_{obsd}=\{\\k_0+k_H[H^+]\}\;[SCN^-]^2+k_r$. 이온세기가 2.84이고 온도가 $25^{\circ}C$일때 $k_f$와 $k_r$의 값은 각각 $5.96{\pm}0.35\;M^{-2}s^{-1}$ 과 $(5.45{\pm}4.77){\times}10^{-4}s^{-1}$이다. $20^{\circ}$∼$35^{\circ}C$일 때 활성화파라미터는 ${\Delta}H^*=38.04{\pm}5.31kJmol^{-1}$ 이고 ${\Delta}S^*=-172.69JK^{-1}mol^{-1}$ 이다. 이들 반응의 메카니즘에 대하여 논의 된다.

• 대한화학회지
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• 제33권2호
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• pp.164-167
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• 1989

분광광도법을 이용하여 $trans-[Cr(tmd)_2FX]^+(X=F^-,\;Cl^-)$ 착이온의 압력과 온도변화에 따른 수화반응의 속도상수를 구하였다. 속도상수의 변화로부터 열역학적 인자를 구하고 이 값을 이용하여 두 착물의 반응메카니즘을 구하였다. 수화반응의 속도는 온도와 압력이 증가함에 따라 증가하였으며, 이 반응의 활성화엔트로피와 활성화부피는 각각 $trans-[Cr(tmd)_2F_2]^+$착이온의 경우 5.2eu와 $-3∼-2\;cm^3mol^{-1}$ 이고 trans-[Cr(tmd)_2FCl]^+$ 착이온의 경우는 -16.62eu와 $-8∼-7\;cm^3mol^{-1}$ 이었다. 이 값들로 보아 $trans-[Cr(tmd)_2F_2]^+$착이온의 수화반응은 교환회합(Ia) 메카니즘으로 진행되고 $trans-[Cr(tmd)_2FCl]^+$ 착이온의 수화반응은 해리(D) 메카니즘으로 진행되는 것으로 생각된다.

• 대한화학회지
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• 제34권5호
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• pp.460-464
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• 1990

산성용액내에서 trans-[$Co(en)_2(NO_2)Cl]^+$ 착물과 [$Fe(H_20)_6]^{2+}$ 착물과의 산화환원반응 속도를 UV/vis-분광광도계로 측정하여 $H^+$가 관여한 반응속도상수 k$_H^+$, 반응차수 및 열역학적 활성화파라메타를 구하였다. Co(III), Fe(II)에 대해 각각 1차, H$^+$에 대해서 1차로 진행되는 총괄반응이 3차 반응이고 이 때, $H^+$가 작용한 속도상수 $k_H^+$는 6.7 ${\times}\;10^{-1}$ $L^2$/mol$^2$·min이였고 $E_a$, ${\{Delta}H^{\neq}$는 14.5 Kcal/mol, 13.8 Kcal/mol ${\{Delta}S^{\neq}$는 -18.3 e.u였다. 이러한 실험자료로부터 내부권 반응임을 알았으며 그 메카니즘을 제안하였다.

• 대한화학회지
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• 제56권2호
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• pp.188-194
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• 2012

양이온성 계면활성제인 TTAB(tetradecyltrimethylammonium bromide) 용액에서 4-알킬벤조산 이성질체들의 가용화 현상을 UV/Vis 분광법을 이용하여 연구하였다. 온도변화에 따른 가용화상수($K_s$)값과 임계미셀농도(CMC)값의 변화를 측정함으로써 열역학적으로 분석하였다. 모든 이성질체들의 가용화에 대한 ${\Delta}G^o{_s}$ 값은 측정범위 내에서 모두 음의 값을 나타내었으며, ${\Delta}H^o{_s}$와 ${\Delta}S^o{_s}$ 값은 모두 양의 값을 나타내었다. 또한 4-알킬벤조산 이성질체들의 가용화현상에 미치는 n-부탄올과 NaCl의 효과에 대하여서도 조사하였다. 이러한 첨가제들은 $K_s$와 CMC 값을 동시에 큰 폭으로 변하게 하였으며, 그 결과 4-알킬벤조산 이성질체들은 미셀 속의 중심부 혹은 깊은 palisade 영역에서 가용화되는 것으로 예측할 수 있었다.

• Bulletin of the Korean Chemical Society
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• 제35권5호
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• pp.1365-1374
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• 2014

Thirteen analogs of tridecapeptide ${\alpha}$-factor (WHWLQLKPGQPMY) of Saccharomyces cerevisiae with C- or N-terminal Trp extension and isosteric replacement by Aib at position 8 and 11, Trp at position 13, D-Ala at position 9, and Orn and Glu at position 6 were synthesized and assayed for their biological activity. Receptor binding assay was carried out using our newly developed spectrophotometric method with detector peptide 14. C- or N-terminal extended analogs, ${\alpha}$-factor-$[Trp]_n$ (n =1-5) 1-5 and $[N-Trp]_1$-${\alpha}$-factor 6, were all less active than native ${\alpha}$-factor and gradual decreases in both activity and receptor affinity were observed with greater Trp extension. Trp-substituted analog at position 13, $[Trp^{13}]{\alpha}$-factor 7, exhibited about 2-fold reductions in both activity and receptor affinity. Aib-substituted analogs, $[Aib^8]{\alpha}$-factor 8 and $[Aib^{11}]{\alpha}$-factor 9, showed 5- to 10-fold reduction in activity as well as 3-fold reduction in receptor affinity compared to native ${\alpha}$-factor. $[Orn^6]{\alpha}$-factor 10 demonstrated strong potency with a 7.0-fold increase in halo activity as well as 1.8-fold increase in receptor affinity compared to native ${\alpha}$-factor. For two double substituted analogs, [$Glu^6,{\small{D}}-Ala^9$]${\alpha}$-factor 12 showed the slightly decreased potency in halo activity compared to analog 10, whereas [$Orn^6,{\small{D}}-Ala^9$]${\alpha}$-factor 11 exhibited 15-fold higher halo activity as well as nearly 3-fold higher receptor affinity compared to native ${\alpha}$-factor.

• 농업과학연구
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• 제43권5호
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• pp.788-793
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• 2016

Post-weaning diarrhea (PWD), mostly caused by enterotoxigenic Escherichia coli (ETEC), remains to be a major source of economic loss in swine industry. The use of the ETEC-oral challenge model is often applied to mimic unsanitary commercial swine farm conditions where pathogens and unknown complex microbes exist and can cause severe infections in pigs. The purpose of this study was (1) to estimate ETEC density using spectrophotometric computation, (2) to determine survivability of ETEC after storing at $-20^{\circ}C$ for 7 days, and (3) to evaluate survivability of ETEC after blending with diluted sweeteners (0, 5, 10, 20, and 40% sucrose in phosphate buffered saline [PBS]). Cell density was quantified using UV-VIS spectrophotometer and counting ETEC colony forming units (cfu) at 0, 30, 60, 90, 120, 150, 180, 210, and 240 min. The established linear equation ($y=0.0031x^2-0.0079x+0.0043$ and $y=0.0046x^2-0.0151x+0.0113$) was used for robust quantification of each ETEC cell density. ETEC stored at $-20^{\circ}C$ showed 108 cfu/mL after thawing and incubation. When ETEC was blended with sweeteners (20 and 40%), survival of ETEC was decreased by 58 and 54% in 5 min post blending. However, addition of 20% of sweetener resulted in a higher survivability than those with other media concentrations. Therefore, the use of ETEC-oral challenge model would be possible as a stable method if we could confirm the appropriate medium that increases survivability of ETEC in weaner pigs.

• Fisheries and Aquatic Sciences
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• 제23권3호
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• pp.6.1-6.9
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• 2020

Background: Halophyte plant (HPs), a salt-resistant flora, has been reported to provide several health benefits, but the knowledge of its cosmeceutical potential is still ambiguous. Here, 70% ethanol extracts of 22 HPs collected from along the coast of South Korea were investigated for their potentials of antioxidant, anti-aging, and whitening properties for use as materials in novel cosmeceuticals. Methods: Antioxidant activities were determined by DPPH (1,1-diphenyl-2-pricrylhydrazyl) free radical and hydrogen peroxide scavenging assays, and skin aging-related enzyme activities (anti-elastase, anti-collagenase, anti-hyaluronidase, and anti-tyrosinase) were evaluated by using the spectrophotometric method. Results: Among the 22 HPs, we found that Ischaemum antephoroides f. coreana and Atriplex gmelinii extracts presented the strongest scavenging effects against DPPH free radical and hydrogen peroxide, respectively. Our finding additionally suggested that Salicornia europaea extract might provide a major source of anti-elastase and anti-hyaluronidase; meanwhile, Rosa rugosa extract showed the highest anti-collagenase effect. Furthermore, the highest tyrosinase inhibitory activity was possessed by Spartina anglica extract. Conclusion: These findings may suggest that halophyte plants showing biological activities may be potent inhibitors of tyrosinase, elastase, collagenase, and hyaluronidase and could be useful for application in cosmeceuticals.