• 한국식품과학회지
• /
• 제27권6호
• /
• pp.891-896
• /
• 1995

식품의 효소적 갈변을 일으키며 생체 내에서는 melanin 생합성을 촉매하는 효소인 tyrosinase의 저해제를 천연물로부터 탐색하기 위하여 mushroom tyrosinase와 L-3,4-dihydroxyphenylalanine을 이용한 효소반응 시스템을 도입하여 채소류, 과실류 및 약용식물류 등의 식용식물체 129종 및 수용성 화합물 15종의 tyrosinase 활성 저해능을 측정하였다. 엽경채류의 경우 무순>레드치커리>냉이>쪽파>브로콜리>꽃양배추의 순으로 약 50% 이상의 높은 저해능을 보였으며 근채류, 버섯류 및 다류에서는 무, 마늘, 팽이버섯, 표고버섯, 느타리버섯, 녹차, 홍차가 50% 이상의 저해능을 보였다. 과채류의 경우 홍고추>모과>아보카도의 순으로 높은 효소저해 효과를 보여 50% 이상의 저해능을 나타내었으나 과실류는 전반적으로 저해능이 낮은 편이었다. 약용식물류에서는 오매>계피>복분자>상백피>측백엽>갈근>작약>산사자의 순서로 50% 이상의 효소활성 저해능을 보였으며, 초본류의 경우 올스파이스, 정향, 계피, 겨자가 50% 이상의 저해능을 보였다. 한편, 분석한 몇가지 수용성 화합물에 있어서는 4-hexylresorcinol, L-cysteine, glutathione, sodium bisulfite, kojic acid가 강력한 tyrosinase 활성 저해효과를 나타냈다.

• 한국환경성돌연변이발암원학회지
• /
• 제17권1호
• /
• pp.17-22
• /
• 1997

We observed the frequency of chromosome aberrations induced by UVB irradiations, and the suppressing effect of tannic acid on chromosome aberrations induced by UVB irradiations in CHL cells, which is a phenolic compound, a hydrolysate of tannin and a components of green tea. UVB doses used for the frequency of chromosome aberrations were from 0.2 to 1.6 KJ/m$^2$ and tannic acid concentrations were from 1.16 $\mu$g/ml to 37.50 $\mu$g/ml. For the observation of suppressing effect of tannic acid on UVB-induced chromosome aberrations, UVB dose was 1.6 KJ/m$^2$ and tannic acid concentrations were 1.0, 2.0, 4.0 $\mu$g/ml. In our study, tannic acid was treated for 24 hours in CHL, cells after UVB irradiation without S9 mix or for 6 hours with S9 mix. From this study, we obtained the following results : (1) The frequency of chromosome aberrations UVB induced were dose-dependently increased. (2) The tannic acid did not induce chromosome aberrations in cultured Chinese hamster cells. (3) UVB-induced chromosome aberrations were suppressed by tannic acid at every concentration from 1.0 $\mu$g/ml to 4.0 $\mu$g/ml with or without metabolic activation. These results suggest that the tannic acid acts as an inhibitor to UVB-induced clastogenicity of the cultured cell.

• Molecules and Cells
• /
• 제22권1호
• /
• pp.113-118
• /
• 2006

Thioredoxin reductase (TrxR), a component of the redox control system involving thioredoxin (Trx), is implicated in defense against oxidative stress, control of cell growth and proliferation, and regulation of apoptosis. In the present study a stable transfectant was made by introducing the vector pcDNA3.0 harboring the fission yeast TrxR gene into COS-7 African green monkey kidney fibroblast cells. The exogenous TrxR gene led to an increase in TrxR activity of up to 3.2-fold but did not affect glutathione (GSH) content, or glutaredoxin and caspase-3 activities. Levels of reactive oxygen species (ROS), but not those of nitric oxide (NO), were reduced. Conversely, 1-chloro-2,4-dinitrobezene (CDNB), an irreversible inhibitor of mammalian TrxR, enhanced ROS levels in the COS-7 cells. After treatment with hydrogen peroxide, the level of intracellular ROS was lower in the transfectants than in the vector control cells. These results confirm that TrxR is a crucial determinant of the level of cellular ROS during oxidative stress as well as in the normal state.

• 한국식품영양학회지
• /
• 제30권5호
• /
• pp.1035-1041
• /
• 2017

(-)-Epigallocatechin-3-gallate (EGCG) is a major catechin found in green tea. It is reported that EGCG possesses various health benefits including anti-cancer, antioxidant, anti-diabetes, and anti-obesity. The objective of this study was to investigate the effects of EGCG on adipogenesis via activation of AMP-activated protein kinase (AMPK) pathway in 3T3-L1 preadipocytes. In order to determine the effects of EGCG on adipogenesis, preadipocyte differentiation was induced in the presence or absence of EGCG ($0{\sim}100{\mu}M$) for a period of 6 days. EGCG significantly inhibited fat accumulation and suppressed the expression of adipogenic specific proteins including peroxisome proliferator-activated receptor (PPAR)-${\gamma}$. Also, EGCG markedly increased the activation of AMPK and acetyl-CoA carboxylase (ACC) and the production of intracellular reactive oxygen species (ROS). However, any pretreatment with a specific AMPK inhibitor, compound C, abolished the inhibitory effects of the EGCG on $PPAR{\gamma}$ expression. This study suggests that EGCG has anti-adipogenic effects through modulation of the AMPK signaling pathway and therefore, may be a promising antiobesity agent.

• 한국식품과학회지
• /
• 제35권6호
• /
• pp.1199-1203
• /
• 2003

한국산 녹차를 70% 에탄올로 추출한 후 Sephadex LH-20과 HPLC를 사용하여 polyphenol을 분리동정하였고 분리된 각 성분들의 angiotensin converting enzyme(ACE) 및 xanthine oxidase, tyrosinase의 저해효과를 확인하였다. 녹차로부터 HPLC로 polyphenol을 분리한 결과 epiafzelechin-$(4{\beta}{\rightarrow}8)$-epiafzelechin, procyanidin B-3-3-O-rhamnose, afzelechin-$(4{\alpha}{\rightarrow}8)$-catechin, prodelphinidin B-5-3,3'-di-O-digallate, (+)-taxifolin-3-O-D-xyloside 등 11종류를 분리하였다. ACE의 저해효과는 prodelphinidin-C-2-3,3'-di-O-gallate $100{\mu}M$에서 68.8%, procyanidin B-2-3,3'-digallate가 54.6%의 저해를 나타내었고, Xanthine oxidase는 prodelphinidin C-2-3,3'-di-O-gallate가 54.5%, procyanidin B-2-3,3'-digallate가 38.2%로 높은 저해효과를 보였다. Tyrosinase의 저해효과는 $100{\mu}M$ 농도에서 prodelphinidin C-2-3,3'-di-O-gallate가 42.1%, procyanidin B-2-3,3'-digallate와 procyanidin B-7이 각각 30.7%, 20.5%의 저해를 나타내었다. 따라서 녹차 추출물로부터 분리한 polyphenol이 혈압예방, 통풍 및 미백효과의 기능성 식품 신소재로서 이용이 가능하다는 것을 확인하였다.

• 생명과학회지
• /
• 제20권12호
• /
• pp.1896-1901
• /
• 2010

본 연구는 가축생균제용 유산균을 Real-time PCR정량분석법을 이용하여 분석하였다. SYBR Green1 방법과 Probe 방법을 이용하여 표준곡선을 제작한 결과, SYBR Green1 방법에서는 Slope 값이 -3.346이었고, Y절편은 33.18, $R^2$ 값은 0.993으로 나타났으며, Probe 방법에서는 Slope값이 -3.321이었고, Y절편은 39.10, $R^2$ 값은 0.995로 나타나, 이를 이용한 표준곡선 제작이 가능함을 알 수 있었다. SYBR Green1 방법을 이용한 생균제의 Lactobacilli 정성 정량 분석결과 Real-time PCR값은 4.46~6.56 log copies로 나타났고, 생균수 측정 결과 값은 5.63~7.59 log CFU/g로 나타났으며, Probe 방법을 이용한 생균제의 Lactobacilli 정성 정량 분석결과에서는 Real-time PCR 값은 5.51~7.00 log copies로 나타났으며, 생균수 측정 결과 값은 5.63~7.59 log CFU/g로 나타났다. 본 연구에서 실시한 RT PCR법은 3~4일이 소요되는 기존의 배지법과 비교하여 24시간 이내에 신속하게 검출이 가능하다고 여겨지며, 또한 RT PCR을 이용한 분석방법에서도 dye 사용과 primer 사용에 따라 결과값이 차이가 나타났음을 확인할 수 있었으며, Probe 방법을 이용하여 실험 한 결과가 민감한 결과를 나타내었음을 확인 할 수 있었다.

• 한국환경과학회지
• /
• 제19권12호
• /
• pp.1323-1334
• /
• 2010

The effect of nitric oxide (NO) on antioxidant system and protective mechanism against oxidative stress under UV-B radiation was investigated in leaves of maize (Zea mays L.) seedlings during 3 days growth period. UV-B irradiation caused a decrease of leaf biomass including leaf length, width and weight during growth. Application of NO donor, sodium nitroprusside (SNP), significantly alleviated UV-B stress induced growth suppression. NO donor permitted the survival of more green leaf tissue preventing chlorophyll content reduction and of higher quantum yield for photosystem II than in non-treated controls under UV-B stress, suggesting that NO has protective effect on chloroplast membrane in maize leaves. Flavonoids and anthocyanin, UV-B absorbing compounds, were significantly accumulated in the maize leaves upon UV-B exposure. Moreover, the increase of these compounds was intensified in the NO treated seedlings. UV-B treatment resulted in lipid peroxidation and induced accumulation of hydrogen peroxide ($H_2O_2$) in maize leaves, while NO donor prevented UV-B induced increase in the contents of malondialdehyde (MDA) and $H_2O_2$. These results demonstrate that NO serves as antioxidant agent able to scavenge $H_2O_2$ to protect plant cells from oxidative damage. The activities of two antioxidant enzymes that scavenge reactive oxygen species, catalase (CAT) and ascorbate peroxidase (APX) in maize leaves in the presence of NO donor under UV-B stress were higher than those under UV-B stress alone. Application of 2-(4-carboxyphenyl)-4, 4, 5, 5-tetramethylimidazoline-1-oxyl-3- oxide (PTIO), a specific NO scavenger, to the maize leaves arrested NO donor mediated protective effect on leaf growth, photosynthetic pigment and free radical scavenging activity. However, PTIO had little effect on maize leaves under UV-B stress compared with that of UV-B stress alone. $N^{\omega}$-nitro-L-arginine (LNNA), an inhibitor of nitric oxide synthase (NOS), significantly increased $H_2O_2$ and MDA accumulation and decreased antioxidant enzyme activities in maize leaves under UV-B stress. This demonstrates that NOS inhibitor LNNA has opposite effects on oxidative resistance. From these results it is suggested that NO might act as a signal in activating active oxygen scavenging system that protects plants from oxidative stress induced by UV-B radiation and thus confer UV-B tolerance.

• 한국식품영양과학회지
• /
• 제21권3호
• /
• pp.255-262
• /
• 1992

단백소화율에 미치는 식이 섬유소의 영향에 대하여 알아보기 위해, 채소류(상치, 깻잎, 고추. 다시마)로부터 추출한 식이 섬유소와 시판용 정제 식이 섬유소 (cellulose, pectin, sodium alginate, gum karaya)를 어류 단백질인 말쥐치 단백질(냉동건조육 및 myofibrils)에 첨가 반응시켜, 단백질 의 소화율에 어느 정도 영향을 미치는가에 대해 알아보았다. 각 시료의 중성세제 추출섬유소 (neutral detergent fiber) 함량은 24.21%(고추) 9.75%(다시마)의 범위였고, 산성세제 추출섬유소 (acid detergent fiber) 함량은 20.85%(고추) 11.97%(깻잎)의 범위였으며, 수용성 섬유소 함량은 13.79%(다시마) 4.41%(상치)의 범위였다. 말쥐치 단백질에 대한 식이 섬유소의 반응 비율을 1 : 1 (wt/wt)로 하고, 37$^{\circ}C$에서 2시간 동안 반응시켰을 때. 말쥐치 단백소화율은 정제 식이 섬유소 첨가의 경우, 1.52%(cellulose) 9.97%(pectin)가 감소되었고. 추출한 식이 섬유소 첨가의 경우, 5.15%(고추) 12.36%(다시마)가 감소되었다. 섬유소의 trypsin 활성저해능은 단백소화율이 감소함에 따라 증가하여, ANRC casein에 대한 soybean trypsin inhibitor 22mg/g (cellulose) 61.82mg/g(gum karaya), 49.75mg/g(고추) 171.52mg/g(상치)에 상응하는 것으로 나타났다. 정제 식이 섬유소에 의한 단백분해효소의 활성 변화는 sodium alginate를 제외하고는 거의 없어, 어류 단백소화율의 저하는 식이 섬유소가 단백질에 직접 결합하여 비소화성 물질을 형성한 결과가 주도하리라 생각되었다. 말쥐치 단백질과 섬유소를 반응시킨 것을 효소 가수분해시킨 후에 측정한 유리 필수 아미노산의 함량은 sodium alginate와 다시마 섬유소의 경우 현저하게 저하하였으며(75% 이상), isoleucine과 valine이 크게 영향을 받았다.

• Journal of Microbiology and Biotechnology
• /
• 제22권3호
• /
• pp.378-384
• /
• 2012

In aquatic invertebrates, particularly marine gastropods, organotin compounds induce irreversible sexual abnormality in females, which is termed imposex, at very low concentrations. Organotin compounds are agonists for nuclear receptors such as RXRs and $PPAR{\gamma}$. However, the imposex phenomenon has not been reported to act as an antagonist on estrogen receptors in other species, including vertebrates and invertebrates. In order to gain insights into the antagonistic activity of organotin compounds on estrogen receptors (ERs), we examined the inhibitive effect of these compounds on estradiol-dependent ${\beta}$-galactosidase activity using the yeast two-hybrid detection system consisting of a combination of the human estrogen receptor ($hER{\beta}$) ligand-binding domain and the co-activator steroid receptor co-activator-1 (SRC1). Tributyltin-hydroxide (TBT-OH) and triphenyltin-chlorine (TPT-Cl) exhibited an inhibitive effect on $E_2$-dependent transcriptional activity, similar to antagonistic chemicals such as 4-hydroxytamoxifen (OHT) or ICI 182,780, at a very low concentration of $10^{-14}$ M TBT or $10^{-10}$ M TPT, respectively. The yeast growth and transcriptional activity with transcriptional factor GAL4 did not exhibit any effect at the tested concentration of TBT or TPT. Moreover, the yeast two-hybrid system using the interaction between p53 and the T antigen of SV40 large did not describe any effect at the tested concentration of OHT or ICI 182,780. However, the interaction between p53 and T antigen was inhibited at a TBT or TPT concentration of $10^{-9}$ M, respectively. These results indicate that TBT and TPT act as inhibitors of ER-dependent reporter gene transcriptional activation and of the interaction between $hER{\beta}$ LBD and the co-activator SRC1 in the yeast two-hybrid system. Consequently, our data could partly explain the occurrence of organotin compound-induced imposex on the endocrine system of mammals, including humans.

• BMB Reports
• /
• 제29권3호
• /
• pp.230-235
• /
• 1996

The interaction of ${\alpha}-ketoglutarate$ dehydrogenase complex (${\alpha}-KGDC$) with a hydrophobic fluorescent probe [1,1'-bi(4-aniline)naphthalene-5,5'-disulfonic acid] (bis-ANS) was studied. The punfied ${\alpha}-KGDC$ was potently inhibited by bis-ANS with an apparent half maximal inhibitory concentration ($IC_{50}$) of 9.8 ${\mu}m$ at pH 8.0. The catalytic activities of both the E1o and E2o subunits were predominantly inhibited while that of the E3 component was hardly affected. The binding of bis-ANS to the enzyme caused a marked enhancement and blue shift from 523 nm to 482 nm in the fluorescence emission spectrum. The dissociation constant ($K_d$) and the number of binding sites (n) were calculated to be 0.87 mM and 158, respectively. Allosteric regulators such as purine nucleotides and divalent cations further increased the fluorescence intensity of the $bis-ANS-{\alpha}-KGDC$ binary complex. These data suggest that the binding of these allosteric regulators to ${\alpha}-KGDC$ may cause the conformational changes in the enzyme and that bis-ANS could be used as a valuable probe to study the interaction of the multi-enzyme complex and its allosteric regulators.