Hyphenated LC-ICP-MS/ESI-MS identification of halogenated metabolites in South African marine ascidian extracts

Extracts of 13 species of marine ascidian collected in Algoa Bay were analyzed by LC-ICP-MS/ESI-MS. This technique allows parallel analysis of the molecular species and the presence of certain elements. The LC-ICP-MS/ESI-MS technique was used to target iodinated metabolites in this study. Three ascidian species afforded the known 3,5–diiodo-4-methoxyphenethylamine (12), which was confirmedby the isolation of this metabolite fromAplidium monile.MS also suggested the presence of theknown 3,5–dibromo-4-methoxyphenethylamine (10) and the new 3-bromo-5–iodo-4-methoxyphenethylamine (11) in the A. monile extract. The presence of the known 3,5-dibromotetramethyltyrosine (21) and the new 3-iodotetramethyltyrosine (23) in extracts of an unidentified Didemnum species was similarly proposed from MS evidence. This is the first report of the occurrence of iodinated metabolites in South African marine invertebrates.IS

Halogenated oxindole and indoles from the South African marine ascidian Distaplia skoogi:

The known 3,6-dibromoindole (1), 6-bromo-3-chloroindole (2) and 6-bromo-2-oxindole (3) were isolated from the marine ascidian (sea squirt) Distapia skoogi collected from Algoa Bay, South Africa. Standard spectroscopic techniques were used to elucidate the structures of 1-3. All three compounds were found to be moderately cytotoxic to metastatic MDA-MB-231 breast cancer cells

Polypropionates from the South African Marine Mollusk <i>Siphonaria oculus</i>

Three new polypropionate metabolites, 6<i>Z</i>,8<i>E</i>-Δ⁸-siphonarienfuranone (<b>1</b>), 6<i>E</i>,8<i>E</i>-Δ⁸-siphonarienfuranone (<b>2</b>), and 6<i>E</i>,8<i>E</i>-3-hydroxy-4,6,8,10,12-pentamethylpentadeca-6,8-dien-5-one (<b>3</b>), and the known polypropionate siphonarienfuranone (<b>4</b>) were isolated from the intertidal South African marine mollusk <i>Siphonaria oculus</i>. Evidence is presented to suggest that <b>1</b>, <b>2</b>, and <b>4</b> may cyclize from an acylic precursor on chromatographic workup of the acetone extract of this mollusk