title: Absolute stereochemistry of fungal beauveriolide III and ACAT inhibitory activity of four stereoisomers.
abstract: Fungal beauveriolide III (BeauIII, 1b), a cyclodepsipeptide inhibiting acyl-CoA:cholesterol acyltransferase (ACAT) and showing antiatherogenic activity in mouse models, consists of L-Phe, L-Ala, D-allo-Ile, and 3-hydroxy-4-methyloctanoic acid (HMA) moieties, but the stereochemistry of the HMA part has not until now been fully defined. To determine it, four HMA stereoisomers were synthesized and labeled with (S)-(+)-2-(anthracene-2,3-dicarboximido)-1-propyl trifluoromethane sulfonate (AP-OTf), a chiral fluorescent reagent. The derivatives were separated by HPLC and compared with the natural HMA derivative, which was thereby identified as (3S,4S)HMA in BeauIII. Furthermore, the four beauveriolide III isomers ((3S,4S)BeauIII (23a), (3R,4R)BeauIII (23b), (3R,4S)BeauIII (23c), and (3S,4R)BeauIII (23d)) were synthesized, and it was shown that all the spectral data for 23a were identical with those for natural 1b. Isomers 23a and 23d showed potent inhibitory activity of lipid droplet accumulation in macrophages, while the other two isomers caused weak inhibition. Thus, the 3S configuration of BeauIII is important for this activity. Furthermore, 23a and 23d showed rather specific inhibition against the ACAT1 isozyme.
authors.affiliation: Kitasato Institute for Life Sciences and Graduate School of Infection Control Sciences, Kitasato University, Minato-ku, Tokyo 108-8641, Japan.
authors.forename: Taichi
authors.initials: T
authors.lastname: Ohshiro
authors.forename: Ichiji
authors.initials: I
authors.lastname: Namatame
authors.forename: Kenichiro
authors.initials: K
authors.lastname: Nagai
authors.forename: Takafumi
authors.initials: T
authors.lastname: Sekiguchi
authors.forename: Takayuki
authors.initials: T
authors.lastname: Doi
authors.forename: Takashi
authors.initials: T
authors.lastname: Takahashi
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Akasaka
authors.forename: Lawrence L
authors.initials: LL
authors.lastname: Rudel
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tomoda
authors.forename: Satoshi
authors.initials: S
authors.lastname: Omura
mesh_terms: D000818:Animals; D047630:Depsipeptides / Q000737:chemistry* / Q000494:pharmacology*; D005658:Fungi / Q000737:chemistry; D006801:Humans; D050356:Lipid Metabolism / Q000187:drug effects; D008055:Lipids / Q000037:antagonists & inhibitors; D008264:Macrophages / Q000378:metabolism; D013237:Stereoisomerism; D002785:Sterol O-Acyltransferase / Q000037:antagonists & inhibitors*; D013329:Structure-Activity Relationship
chemical_list: D047630:Depsipeptides; D008055:Lipids; C013833:beauverolides; D002785:Sterol O-Acyltransferase; C493492:sterol O-acyltransferase 1