Rhizochalins C and D from the Sponge Rhizochalina incrustata. A Rare threo-Sphingolipid and a Facile Method for Determination of the Carbonyl Position in α,ω-Bifunctionalized Ketosphingolipids

Abstract

Rhizochalins C and D ( 1, 2), new representatives of two-headed glycosphingolipids, were isolated from the sponge Rhizochalina incrustata. Rhizochalin D is an unexpected C 29 homologue of the canonical C 28 dimeric sphingolipid structures. Their structures including absolute configurations were established using spectroscopic data, micromolar-scale Baeyer-Villiger oxidation, and LCMS interpretation of the products. Application of the latter method leads to a revision of the structure of oceanapiside and placement of the keto group at C-18 rather than C-11.

Marine Two‐Headed Sphingolipid‐Like Compound Rhizochalin Inhibits EGF‐Induced Transformation of JB6 P+ Cl41 Cells

“…Rhizochalin and its analogs and derivatives were extracted, purified and prepared as described previously [1,[7][8][9] and were pure in accordance with NMR, MS, TLC, and HPLC data. Briefly, the fresh collection of the sponges R. incrustata was immediately lyophilized and kept at -20°C.…”

“…1) [1], a series of related natural products have been reported [2][3][4][5][6][7][8][9][10]. Two-headed sphingolipid-like compounds differ from classical sphingolipids in the presence of polar groups in a,x-positions.…”

“…Rhizochalin and analogs were reported to possess antibacterial, antifungal, and cytotoxic activities [2][3][4][5][6][7][8][9][10].…”

Differential Induction of Apoptosis of Leukemic Cells by Rhizochalin, Two Headed Sphingolipids from Sponge and Its Derivatives

“…The chemicals were extracted, purified, and prepared as described previously. 7,9) Cell Culture Human promyelocytic HL-60 cells and human acute monocytic leukemia THP-1 (THP-1) cells were obtained from the Korean Cell Line Bank (Seoul National University, Seoul, Korea) and maintained in RPMI 1640 medium supplemented with 10% fetal bovine serum (FBS), 100 U/ml penicillin and 100 mg/ml streptomycin, and were incubated at 37°C in a humidified atmosphere of 95% air/5% CO 2 .…”

“…1), isolated in 1989 by our group from the Madagascarian sponge Rhizochalin incrustata. 6) The group of two-headed sphingolipids includes a limited number of compounds: Rhz, Rhz A, Rhz C, Rhz D and rhizochalinin A from the marine sponge Rhizochalina incrustata, [6][7][8][9][10] oceanapiside from Oceanapia phillipensis, 11) oceanalin A, Rhz B, and rhizochalinin B from Oceanapia sp., 7,12) calyxoside from Calyx sp., 13) leucettamols A and B from Leucetta leptorhapsis 14) and compound BRS1 from an unidentified sponge. 15) Their structures have been established on the basis of spectroscopic data and chemical transformations.…”