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Isorhizochalin: a Minor Unprecedented Bipolar Sphingolipid of Stereodivergent Biogenesis from the Rhizochalina incrustata
Author(s) -
Makarieva Tatya.,
Zakharenko Alexander M.,
Dmitrenok Pavel S.,
Guzii Alla G.,
Denisenko Vladimir A.,
Savina Alexandra S.,
Dalisay Doralyn S.,
Molinski Tadeusz F.,
Stonik Valentin A.
Publication year - 2009
Publication title -
lipids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.601
H-Index - 120
eISSN - 1558-9307
pISSN - 0024-4201
DOI - 10.1007/s11745-009-3360-0
Subject(s) - stereochemistry , chemistry , sphingolipid , biogenesis , epimer , context (archaeology) , aglycone , thioester , absolute configuration , biosynthesis , diastereomer , biochemistry , glycoside , biology , enzyme , paleontology , gene
Isorhizochalin ( 1 ) was isolated as its peracetate from the EtOH extract of the sponge Rhizochalina incrustata . Its structure and absolute stereochemistry were elucidated as (2 S ,3 R ,26 R ,27 R )‐2,27‐diamino‐3‐ O ‐β‐ d ‐galactopyranosyl‐oxy‐26‐hydroxyoctacosan‐18‐one by extensive NMR, MS studies, chemical transformations, including micromolar‐scale Baeyer–Villiger oxidation, and by analysis of CD spectra of isorhizochalinin perbenzoate ( 2b ). Isorhizochalin is an unprecedented C‐2 epimer of rhizochalin having an erythro configuration at the glycosylated 2‐amino‐3‐alkanol α‐terminus in contrast with a canonical threo configuration for other representatives of this structural group. Probable biogenesis of 1 is discussed in the context of known sphingolipid biosynthesis beginning with condensation of alanine with a fatty acyl CoA thioester. The aglycone, isorhizochalinin ( 2a ), shows cytotoxicity against human leukemia HL‐60 and THP‐1 cells with IC 50 values of 2.90 and 2.20 μM, respectively.