title: Isolation and characterization of a human intestinal bacterium, Eubacterium sp. ARC-2, capable of demethylating arctigenin, in the essential metabolic process to enterolactone.
abstract: Plant lignans, such as pinoresinol diglucoside, secoisolariciresinol diglucoside and arctiin, are metabolized to mammalian lignans, enterolactone or enterodiol, by human intestinal bacteria. Their metabolic processes include deglucosylation, ring cleavage, demethylation, dehydroxylation and oxidation. Here we isolated an intestinal bacterium capable of demethylating arctigenin, an aglycone of arctiin, to 2,3-bis(3,4-dihydroxybenzyl)butyrolactone (1) from human feces, and identified as an Eubacterium species (E. sp. ARC-2), which is similar to Eubacterium limosum on the basis of morphological and biochemical properties and 16S rRNA gene sequencing. By incubating with E. sp. ARC-2, arctigenin was converted to 1 through stepwise demethylation. Demethylation of arctigenin by E. sp. ARC-2 was tetrahydrofolate- and ATP-dependent, indicating that the reaction was catalyzed by methyltransferase. Moreover, E. sp. ARC-2 transformed secoisolariciresinol to 2,3-bis(3,4-dihydroxybenzyl)-1,4-butanediol by demethylation.
authors.affiliation: Institute of Natural Medicine, University of Toyama, Toyama, Japan.
authors.forename: Jong-Sik
authors.initials: JS
authors.lastname: Jin
authors.forename: Yu-Feng
authors.initials: YF
authors.lastname: Zhao
authors.forename: Norio
authors.initials: N
authors.lastname: Nakamura
authors.forename: Teruaki
authors.initials: T
authors.lastname: Akao
authors.forename: Nobuko
authors.initials: N
authors.lastname: Kakiuchi
authors.forename: Masao
authors.initials: M
authors.lastname: Hattori
mesh_terms: D015107:4-Butyrolactone / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000494:pharmacology; D001711:Biotransformation; D005051:Eubacterium / Q000145:classification / Q000187:drug effects / Q000302:isolation & purification* / Q000502:physiology*; D005243:Feces / Q000382:microbiology; D005663:Furans / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D007422:Intestines / Q000382:microbiology*; D017705:Lignans / Q000737:chemistry / Q000378:metabolism*; D015394:Molecular Structure; D010802:Phylogeny; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D013763:Tetrahydrofolates / Q000494:pharmacology; D013997:Time Factors
chemical_list: D005663:Furans; D017705:Lignans; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; D013763:Tetrahydrofolates; C030371:5,6,7,8-tetrahydrofolic acid; D000255:Adenosine Triphosphate; D015107:4-Butyrolactone; C071942:arctigenin; C029497:2,3-bis(3'-hydroxybenzyl)butyrolactone