• Proceedings of the PSK Conference
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• 2003.10b
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• pp.132.2-132.2
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• 2003

Vibrio vulnificus, a Gram-negative estuarine bacterium, is the causative agent of food-borne diseases, such as life-threatening septicemia. V. vulnificus penetrating into the intestinal epithelial barrier stimulates an inflammatory response in the adjacent intestinal mucosa. Therefore, interaction between V. vulnificus and intestinal cells is important for understanding of both the immunology of mucosal surfaces and V. vulnificus. In this study we investigated the effects of V. vulnificus infection on cytokine gene expression of human intestinal epithelial cells, Caco-2 and INT-407 cells. (omitted)

• Journal of Microbiology and Biotechnology
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• v.15 no.3
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• pp.519-524
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• 2005

An ${\alpha}$-L-rhamnosidase (EC 3.2.1.40.), which transforms quercitrin to quercetin, was purified from Fusobacterium K-60, a human intestinal anaerobic bacterium. The specific activity of the purified ${\alpha}$-L-rhamnosidase was 2.89 mol/min/mg protein. ${\alpha}$-L-Rhamnosidase, whose molecular size was 170 kDa by gel filtration, was composed of four subunits ($M_r$ 41,000 Da) with pI and optimal pH values of 5.2 and 5.5-7.0, respectively. The apparent $K_m$ and $V_{max}$ values for p-nitrophenyl-${\alpha}$-L-rhamnopyranoside and quercitrin were determined to be 0.057 mM and 3.4 mol/min/mg, and 0.077 mM and 5.0 mol/min/mg, respectively. This enzyme was strongly inhibited by $Cu^{2+},\;Mn^{2+}$, L-rhamnose, and p-chlormercuriphenylsulfonic acid. These findings suggest that the biochemical properties and substrate specificity of the purified enzyme are different from those of the previously purified ${\alpha}$-L-rhamnosidase. This is the first reported purification of quercitrin-hydrolyzing ${\alpha}$-L-rhamnosidase from intestinal bacteria.

• Microbiology and Biotechnology Letters
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• v.23 no.6
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• pp.633-640
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• 1995

As a result of screening the medicinal herbs which selectively control human intestinal microflora, water extract of Akebia quinata Decaisne was proved to have a strong inhibitory activity against the growth of Clostridium pefringens, a major harmful intestinal bacterium. The anti-bacte-rial activity was stable under the thermal treatment at 100$\circ$C for 120 min and in a range of pH 1 to 11. In addition, the water extract of Akebia quinata Decaisne showed the antibacterial activities against five different strains of Clostridia including C. perfringens. On the contrary, the extract did not inhibit the growths of Bifidobacterium, Lactobacillus, Escherichia coli, Enterococcus faecalis. The extract, however, suppressed markedly the growth of Bacteroides fragilis and Staphylococcus aureus in vitro. Alike in the mixed culture inoculated with human feces as starter, in vivo tests using rats showed that the extract tends to increase the numbers of Bifidobacteria and Lactobacilli in the intestinal microflora of rats, whereas those of Clostridia were attenuated.

• Journal of Applied Biological Chemistry
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• v.65 no.4
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• pp.447-451
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• 2022

Phytoestrogenic S-equol production in human gut exclusively depends on the biotransformation of daidzein to dihydrodaidzein (DHD). With a growing demand for the DHD enriched biomaterials, the commercial soybean hypocotyl extract (SHE) was chosen as a substrate for the microbial DHD production by human gut bacterium MRG-1, anaerobic DHD producer. To optimize the production of DHD, anaerobic fermentation conditions, including sterilization time, growth stage of inoculum, and growth media, were investigated. Maximum DHD production (1.2 g/L) was achieved after 48 h incubation when 1% (w/v) of SHE in the 20-min-sterilized Gifu Anaeboic Medium media was inoculated with OD₆₀₀ 0.3-0.4 of MRG-1. This is the first report that crude soy biomaterial, instead of pure compounds, such as daidzin and daidzein, is utilized for the production of the DHD enriched biomaterial.

• Archives of Pharmacal Research
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• v.24 no.6
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• pp.564-567
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• 2001

The fecal ${\beta}-glucuronidase$ activity of patients with colon cancer and healthy controls were measured to determine the relationship between the fluctuation of intestinal bacterial ${\beta}-glucuronidase$ and colon cancer. The fecal ${\beta}-glucuronidase$ activity of patients with colon cancer was 1.7 times higher than that of the healthy controls. However, when these fecal specimens were sonicated, the enzyme activity of patients with colon cancer was 12.1 times higher than that of the healthy controls. The fecal ${\beta}-glucuronidase$ activity of human Intestinal bacteria was drastically induced by its substrate or the bile secreted after a subcutaneous injection of 1,2-dimethylhydrazine (DMH) and benzo[a]pyrene into rats. DMH-and benzo[a]pyrene-treated biles induced ${\beta}-glucuronidase$ activity in the human intestinal microflora by approximately 1.5- and 2.3-fold, respectively. They also induced ${\beta}-glucuronidase$ in E. coli HGU-3, which is a ${\beta}-glucuronidase$-producing bacterium from the human intestine. D-saccharic acid 1,4-lactone similarly inhibited fecal ${\beta}-glucuronidase$ in several patients with colon cancer in addition to the healthy controls. This suggests that potent ${\beta}-glucuronidase$ activity is a prime factor in the etiology of colon cancer.

• Journal of Microbiology and Biotechnology
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• v.14 no.4
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• pp.766-771
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• 2004

Julong 601, a Gram-positive anaerobic bacterium strain capable of cleaving the C-ring of isoflavones daidzein and genistein, was isolated from human feces. BLAST search revealed that its complete 16S rDNA gene sequence has 99% similarity to Eubacterium ramulus. Metabolites of daidzein and genistein were determined as O-desmethylangolensin (O-Dma) and 2-(4-hydroxyphenyl) propionic acid (2-HPPA), respectively, based on UV, EI-MS, and $^1H$ and ^{13}C$ NMR spectral analyses. Enantiomers of O-Dma and 2-HPPA were isolated by chiral stationary-phase HPLC (CSP HPLC). Cleavage of the C-ring of daidzein and genistein by strain Julong 601 was highly enantioselective. Specific rotation ([$\alpha]_D$) and circular dichroism (CD) spectra of the enantiomers are reported here for the first time. Biotransformation kinetics of daidzein and genistein indicated that the C-ring of genistein has a higher susceptibility to bacterial degradation than that of daidzein.

• Archives of Pharmacal Research
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• v.19 no.1
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• pp.41-45
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• 1996

After rutin(50-1500 mg/kg) was administered orally to rats, the relationship between its metabolites and mutagenicity was investigated. Quercetin conjugates were detected in the urine of rats treated with more than 150 mg/kg. Administration of rutin less than 100 mg/kg resulted in phenolic acid-like metabolites. However, intact rutin was not detected in the urine of rats treated with different amounts. When rutin was cultured with human intestinal bacteria, the amount of quercetin was increased gradually with a corresponding decrease in the level of rutin and then quercetin was decreased gradually with a corresponding increase in the level of unidentified compounds. The ring fission bacterium of quercetin of was Pediococcus Q-05. These results suggest that rutin could be metabolized and transformed from mutagenic to nonmutagenic by intestinal bacteria in human intestine.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.04a
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• pp.98-98
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• 2018

Glycyrrhizin은 감초의 주성분으로 많은 생리활성을 나타내는 성분이다. 감초를 복용하게 되면, 글리시리진은 장내에 서식하고 있는 장내세균에 의해 glycyrrhetic acid로 대사된다. 하지만, 지금까지 대사반응에 관여하고 있는 균주가 분리 후 자원화되지 않았다. 본 연구를 통해 사람의 대변으로부터 glycyrrhizin을 대사하는 균주로 분리된 strain GLY의 16S rRNA 유전자를 분석한 결과, Enterococcus faecium과 99%의 상동성을 보여, Enterococcus faecium GLY (Genebank No. MH048988)로 명명하였다. 대사활성의 특성을 검토하기 위하여 time course, 기질의 농도에 따른 대사활성의 변화, 근연 균주와 대사활성 비교를 실시하였다. Time course 실험에서 GLY균주가 증식함에 따라 기질인 glycyrrhizin은 줄어들고, 대사산물인 glycyrrhetic acid는 새로 생성되었다. 또한, 기질의 농도에 따른 대사활성의 차이 검토를 위해 여러 농도를 처리하여 배양하였을 때, 1.0mM을 처리한 샘플에서 최대값의 대사물 농도를 보였다. Enterococcus faecium와의 근연균주를 이용하여 glycyrrhizin 대사활성을 측정한 결과, strain GLY 균주가 가장 큰 대사능을 가지고 있었다. 본 연구는 앞으로 glycyrrhizin 생체이용 및 대사 연구를 위한 기초연구가 될 것이며, 장내세균에 의한 생약성분의 대사를 이해하는데 도움이 될 수 있다.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.1
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• pp.1-4
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• 2013

Background: The age-adjusted incidence rate of prostate cancer (PCa) has been reported to be lower among Asians than Western populations. A traditional Japanese meal, high in soybean products or isoflavones, may be associated with a decreased risk of PCa. Equol, which is converted from daidzein by human intestinal flora, is biologically more active than any other isoflavone aglycone. Materials and Methods: We reviewed not only recent epidemiological studies on association of isoflavones with PCa risk, but also recent research on human intestinal bacteria responsible for converting daidzein into equol. Studies were systematically searched from the database published within the last 5 years of from 2008-2012. Results: Five out of 6 articles showed significant association of isoflavones with a decreased risk of PCa, and two of them consistently showed that equol-producers carry a significantly reduced risk of PCa. Furthermore, 5 human intestinal bacteria that can convert daidzein into equol were identified in the last 5 years. Conclusions: If equol can reduce risk of PCa, a possible strategy for reducing the risk of PCa may be to increase the proportion of equol-producers by changing the intestinal flora to carrying an equol-producing bacterium with dietary alteration or probiotic technology.

• Proceedings of the PSK Conference
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• 2001.04a
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• pp.180.1-180.1
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• 2001