title: Novel, major 2α- and 2β-hydroxy bile alcohols and bile acids in the bile of Arapaima gigas, a large South American river fish.
abstract: Bile alcohols and bile acids from gallbladder bile of the Arapaima gigas, a large South American freshwater fish, were isolated by reversed-phase high-performance liquid chromatography. The structures of the major isolated compounds were determined by electrospray-tandem mass spectrometry and nuclear magnetic resonance using (1)H- and (13)C-NMR spectra. The novel bile salts identified were six variants of 2-hydroxy bile acids and bile alcohols in the 5α- and 5β-series, with 29% of all compounds having hydroxylation at C-2. Three C27 bile alcohols were present (as ester sulfates): (24ξ,25ξ)-5α-cholestan-2α,3α,7α,12α,24,26-hexol; (25ξ)-5β-cholestan-2β,3α,7α,12α,26,27-hexol, and (25ξ)-5α-cholestan-2α,3α,7α,12α,26,27-hexol. A single C27 bile acid was identified: (25ξ)-2α,3α,7α,12α-tetrahydroxy-5α-cholestan-26-oic acid, present as its taurine conjugate. Two novel C24 bile acids were identified: the 2α-hydroxy derivative of allochenodeoxycholic acid and the 2β-hydroxy derivative of cholic acid, both occurring as taurine conjugates. These studies extend previous work in establishing the natural occurrence of novel 2α- and 2β-hydroxy-C24 and C27 bile acids as well as C27 bile alcohols in both the normal (5β) as well as the (5α) "allo" A/B-ring juncture. The bile salt profile of A. gigas appears to be unique among vertebrates.
authors.affiliation: Department of Chemistry, College of Humanities and Sciences, Nihon University, Tokyo, Japan.
authors.forename: Rika
authors.initials: R
authors.lastname: Sato née Okihara
authors.affiliation: Department of Chemistry, College of Humanities and Sciences, Nihon University, Tokyo, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Saito
authors.affiliation: Department of Chemistry, College of Humanities and Sciences, Nihon University, Tokyo, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Ogata
authors.affiliation: Department of Chemistry, College of Humanities and Sciences, Nihon University, Tokyo, Japan.
authors.forename: Naoya
authors.initials: N
authors.lastname: Nakane
authors.affiliation: Department of Chemistry, College of Humanities and Sciences, Nihon University, Tokyo, Japan.
authors.forename: Kazunari
authors.initials: K
authors.lastname: Namegawa
authors.affiliation: Department of Chemistry, College of Humanities and Sciences, Nihon University, Tokyo, Japan.
authors.forename: Shoutaro
authors.initials: S
authors.lastname: Sekiguchi
authors.affiliation: Department of Chemistry, College of Humanities and Sciences, Nihon University, Tokyo, Japan.
authors.forename: Kaoru
authors.initials: K
authors.lastname: Omura
authors.affiliation: Faculty of Pharmaceutical Sciences, Kinki University, Higashi-Osaka, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kurabuchi
authors.affiliation: Faculty of Pharmaceutical Sciences, Kinki University, Higashi-Osaka, Japan.
authors.forename: Kuniko
authors.initials: K
authors.lastname: Mitamura
authors.affiliation: Faculty of Pharmaceutical Sciences, Kinki University, Higashi-Osaka, Japan.
authors.forename: Shigeo
authors.initials: S
authors.lastname: Ikegawa
authors.affiliation: Dallas Zoo, Dallas, TX, USA.
authors.forename: Jan
authors.initials: J
authors.lastname: Raines
authors.affiliation: Department of Medicine, University of California, San Diego, CA, USA.
authors.forename: Lee R
authors.initials: LR
authors.lastname: Hagey
authors.affiliation: Department of Medicine, University of California, San Diego, CA, USA.
authors.forename: Alan F
authors.initials: AF
authors.lastname: Hofmann
authors.affiliation: Department of Chemistry, College of Humanities and Sciences, Nihon University, Tokyo, Japan. Electronic address: takaiida@chs.nihon-u.ac.jp.
authors.forename: Takashi
authors.initials: T
authors.lastname: Iida
mesh_terms: D000818:Animals; D001647:Bile Acids and Salts / Q000737:chemistry / Q000378:metabolism; D002777:Cholestanols / Q000737:chemistry / Q000378:metabolism; D005399:Fishes / Q000378:metabolism*
chemical_list: D001647:Bile Acids and Salts; D002777:Cholestanols
keywords: 2α-Hydroxylated 5α-bile acid; 2α-Hydroxylated 5α-bile alcohol; 2β-Hydroxylated 5β-bile acid; 2β-Hydroxylated 5β-bile alcohol; Arapaima gigas; Bile salt