Natural pericosines B and C as enantiomeric mixtures: Direct evidence by chiral HPLC analysis

Abstract

Pericosines are carbasugar-type metabolites of Periconia byssoides OUPS-N133, a fungus that was originally separated from the sea hare Aplysia kurodai. It has been reported that pericosines C and E are enantiomeric mixtures. The difference in specific rotation between natural pericosine C and the synthetic one led to the conclusion that natural pericosine C is an enantiomeric mixture. Meanwhile, the small specific rotation of natural pericosine B compared to that of the synthetic one led to the deduction that natural pericosine B might also be an enantiomeric mixture. Then, racemic pericosines B and C were synthesized, and the direct enantioseparation of these racemic carbasugars was conducted with CHIRALPAK® IA and CHIRALPAK® AY-H, which are suitable columns for racemic pericosines B and C, respectively. Using chiral HPLC, we conclude that natural pericosines B and C exist as enantiomeric mixtures. A rare example of the application of direct chiral HPLC analysis to intact sugars or carbasugars was provided.

α-Pyrones with Diverse Hydroxy Substitutions from Three Marine-Derived Nocardiopsis Strains

“…Similarly, compound 9 was isolated, respectively, from two different strains (SCSIO 04583 and SCSIO KS107), and it was confirmed as nonracemic mixtures containing (7 S )- and (7 R )-hydroxymucidone in different ratios, in which (7 R )-hydroxymucidone was a new compound. Enantiomeric mixtures as natural products have some precedents, and most of them are derived from marine fungi, including trichodenone A from a marine sponge-associated Trichoderma harzianum, pericosines B and C from sea hare-derived Periconia byssoide, and penicyrones A and B produced by the marine-derived Penicillium sp. TPU1271 .…”

“…Enantiomeric mixtures as natural products have some precedents, 16a and most of them are derived from marine fungi, including trichodenone A from a marine spongeassociated Trichoderma harzianum, 25 pericosines B and C from sea hare-derived Periconia byssoide, 26 and penicyrones A and B produced by the marine-derived Penicillium sp. TPU1271.…”

Synthesis of Natural O-Linked Carba-Disaccharides, (+)- and (−)-Pericosine E, and Their Analogues as α-Glucosidase Inhibitors

“…15:1. Gradual and careful addition of Oxone ® at −15 °C to a H 2 O–trifluoroacetone solvent system for in situ generation of TFDO was required in this process, otherwise the inseparable regioisomer was present in the product [ 12 , 28 , 33 ]. Details of reaction condition optimization can be found in our previous communication [ 15 ].…”

Nocapyrones: α- and γ-Pyrones from a Marine-Derived Nocardiopsis sp.

“…However, the anteiso -methyl branching in 4 was confirmed as a mixture of ( R )- and ( S )-configurations in a ratio of 2:3. Along with the advances in synthetic and analytical techniques, several enantiomeric mixtures have been discovered in natural products (Figure 9) [39,40,41]. Many of them are marine-derived: trichodenone A, an antitumor metabolite of Trichoderma harzianum isolated from marine sponge ( Halichondria okadai ), is an ( R )- and ( S )-enantiomeric mixture [39]; pericosines B and C, metabolites of Periconia byssoide isolated from sea hare Aplysia kurodai , bearing four chiral centers are also enantiomeric mixtures [40].…”