New Cyclic Peroxides from the Philippine Sponge Plakinastrella sp.

Abstract

Three new cyclic peroxides 5-7 and a new carboxylic acid ester 8 were isolated as minor metabolites from the hexane extract of a Plakinastrella species from the Philippines. The structures of compounds 5-8 were elucidated by interpretation of spectral data and by chemical interconversion, and the absolute stereochemistry of peroxide 6 was determined by application of Mosher's method to a derivative. Although the major compounds in the sponge showed activity against Candida albicans prior to decomposition, the minor metabolites 5-8 are essentially inactive.

Biomedical Compounds from Marine organisms

“…All compounds have been found to inhibit the growth of HCT-116 cells [79]. A peroxylactone originally isolated from a Plakinastrella species [80] has been synthesized as a racemic mixture [81]. Two new 1,2-dioxolane peroxide acids have been isolated from Porolithon onkodes [82].…”

Peroxy natural products

“…Whilst the trivial name plakortolide I has been proposed for an unnamed plakortolide metabolite 32 from the Philippine Sponge Plakinastrella sp., whose absolute stereochemistry was determined by application of Mosher's method to a derivative. 14 The authors also detail the unreliability of specific rotation measurements in the determination of absolute configuration within the plakortolide class of metabolites in the same paper. 13 The first total synthesis of 32 has been achieved using a [2 + 4] photocycloaddition of a singlet oxygen to a diene and iodolactonization as key steps.…”

“…247 A different species of Aster, A. spathulifofius, provided further related 7α-hydroperoxymanool 411 that showed moderate cytotoxicity against human cancer cells. 179 Other compounds of this type included (8S)-hydroperoxy-(13S)-hydroxy-9(11), 14 …”

Synthetic examination of incorrectly proposed structures of biomolecules

“…In 1998, Faulkner and co‐workers isolated a new methyl ester as a constituent of the sponge, Plakinastrella sp., and proposed its structure as methyl (5 Z ,9 Z )‐17‐methylnonadeca‐5,9‐dienoate ( O ) 39. In 2001, we synthesized its ( R )‐enantiomer by Wittig reaction between 27 and 28 40.…”