Jong-Sik Jin

Slackia equolifaciens sp. nov., a human intestinal bacterium capable of producing equol

An equol-producing bacterium, strain DZE(T), which was isolated from human faeces, was characterized by morphological, biochemical and molecular methods. The isolate was Gram-positive, obligately anaerobic, non-spore-forming, asaccharolytic and rod-shaped. 16S rRNA gene sequence analysis showed 92.8, 91.0, 91.1 and 90.6% similarities with Slackia faecicanis, Slackia exigua, Slackia heliotrinireducens and Slackia isoflavoniconvertens, respectively. Based on these data, we propose a novel species of the genus Slackia, Slackia equolifaciens sp. nov. The major cellular fatty acids are C14:0, C18:1omega9c and C18:1omega9c DMA (dimethyl acetal). The DNA G+C content of the strain is 60.8 mol%. The type strain of S. equolifaciens sp. nov. is DZET (=JCM 16059T =CCUG 58231T).

Effects of green tea consumption on human fecal microbiota with special reference to Bifidobacterium species

Green tea is one of the most popular beverages in the world. Its beneficial health effects and components have been extensively reviewed. However, little is known about the influence of green tea consumption on the human intestinal microbiota (HIM), which plays a crucial role in human health. Ten volunteers who did not usually consume green tea, drank it for 10 days and then stopped drinking it for 7 days. Their fecal samples were collected at three time points: before beginning the 10‐day green‐tea regime, at the conclusion of that 10 days, and 7 days after stopping the regime. Their fecal samples were analyzed by terminal restriction fragment length polymorphism with specific primer‐restriction enzyme systems for HIM and by using a real‐time PCR method for the Bifidobacterium species. Although the HIM of each subject was relatively stable, the proportion of Bifidobacterium species played an important role in the classification of their fecal microbiota. Although there were inter‐individual differences in the Bifidobacterium species, an overall tendency for the proportion of bifidobacteria to increase because of green tea consumption was noted. However, little change was observed in the composition of Bifidobacterium species in each sample. This suggests that the change in proportion was induced, not by an inter‐species transition, but by an intra‐species increase and/or decrease. In conclusion, green tea consumption might act as a prebiotic and improve the colon environment by increasing the proportion of the Bifidobacterium species.

Further Studies on a Human Intestinal Bacterium Ruminococcus sp. END-1 for Transformation of Plant Lignans to Mammalian Lignans

A human intestinal bacterium Ruminococcus (R.) sp. END-1 capable of oxidizing (-)-enterodiol to (-)-enterolactone, enantioselectively, was further investigated from the perspective of transformation of plant lignans to mammalian lignans; A cell-free extract of the bacterium transformed (-)-enterodiol to (-)-enterolactone through an intermediate, enterolactol. The bacterium showed not only oxidation but also demethylation and deglucosylation activities for plant lignans. Arctiin and secoisolariciresinol diglucoside were converted to (-)-dihydroxyenterolactone and (+)-dihydroxyenterodiol, respectively. Moreover, by coincubation with Eggerthella sp. SDG-2, the bacterium transformed arctiin and secoisolariciresinol diglucoside to (-)-enterolactone and (+)-enterodiol, respectively.

Ligand Binding Affinities of Arctigenin and Its Demethylated Metabolites to Estrogen Receptor Alpha

Phytoestrogens are defined as plant-derived compounds with estrogen-like activities according to their chemical structures and activities. Plant lignans are generally categorized as phytoestrogens. It was reported that (−)-arctigenin, the aglycone of arctiin, was demethylated to (−)-dihydroxyenterolactone (DHENL) by Eubacterium (E.) sp. ARC-2. Through stepwise demethylation, E. sp. ARC-2 produced six intermediates, three mono-desmethylarctigenins and three di-desmethylarctigenins. In the present study, ligand binding affinities of (−)-arctigenin and its seven metabolites, including DHENL, were investigated for an estrogen receptor alpha, and found that demethylated metabolites had stronger binding affinities than (−)-arctigenin using a ligand binding screen assay method. The IC50 value of (2R,3R)-2-(4-hydroxy-3-methoxybenzyl)-3-(3,4-dihydroxybenzyl)-butyrolactone was 7.9 × 10−4 M.

Identification of Human Intestinal Microbiota of 92 Men by Data Mining for 5 Characteristics, i.e., Age, BMI, Smoking Habit, Cessation Period of Previous Smokers and Drinking Habit

The intestinal microbiota compositions of 92 men living in Japan were identified following consumption of identical meals for 3 days. Fecal samples were analyzed by terminal restriction fragment length polymorphism with 4 primer-restriction enzyme systems, and the 120 obtained operational taxonomic units (OTUs) were analyzed by Data mining software focusing on the following 5 characteristics, namely, age, body mass index, present smoking habit, cessation period of previous smokers and drinking habit, according to the answers of the subjects. After performing Data mining analyses with each characteristic, the details of the constructed Decision trees precisely identified the subjects or discriminated them into various suitable groups. Through the pathways to reach the groups, practical roles of the related OTUs and their quantities were clearly recognized. Compared with the other identification methods for OTUs such as bicluster analyses, correlation coefficients and principal component analyses, the clear difference of this Data mining technique was that it set aside most OTUs and emphasized only some closely related ones. For example for a selected characteristic, such as smoking habit, only 7 OTUs out of 120 were able to identify all smokers, and the remaining 113 OTUs were thought of as data noise for smoking. Data mining analyses were affirmed as an effective method of subject discrimination for various physiological constitutions. The species of bacteria that were closely related to heavy smokers, i.e., HaeIII-291, were also discussed.

A review on pharmacological properties of Bangpungtongsung-san in obesity - Focused on Japanese researches -

Objectives : Excessive nutrition intake and lack of physical activity induce obesity through accumulation of fat in human body. The obesity have been categorized as a disease and known to cause several chronic diseases and cancers. In Japan, Bangpungtongsung-san has been applied as one of the therapies of the obesity and its pharmacological uses have been studied for a long time. The purpose of this study is reviewing researches of Bangpungtongsung-san related to the obesity.