The crude EtOH extract of an Echinodictyum sp. collected during trawling operations in the Great Australian Bight, Australia, displayed antibacterial and antiparasitic properties. Bioassay-directed fractionation yielded three novel sulfonic acids, the echinosulfonic acids A to C (1-3), and a new sulfone, echinosulfone A (4). Structures were assigned to these compounds on the basis of detailed spectroscopic analysis. It was determined that echinosulfonic acids A-C (1-3) and echinosulfone A (4) contributed to the antibacterial but not antiparasitic activity of the crude extract.

A Sigmosceptrella sp. from the Great Australian Bight, Australia, has yielded the new norditerpene cyclic peroxide, nuapapuin A (2a), and the norsesterterpene cyclic peroxide sigmosceptrellin D (3a), characterized as the corresponding methyl esters 2b and 3b. The crude methylated sponge extract also yielded the new norsesterterpene cyclic peroxide sigmosceptrellin E methyl ester (4). Relative stereochemistry about C2, C3, and C6 was assigned by established empirical rules and absolute stereochemistry by the advanced Mosher procedure. A plausible biosynthetic pathway has been proposed that rationalizes key transformations in the biosynthesis of all known norterpene cyclic peroxides and related norterpene ketones, dienes and sigmosceptrins.

The new diketopiperazine dimer 1, as well as the known compounds TMC-256A1 (2), TMC-256C1 (3), and demethylkotanin (4), were isolated from a culture of Aspergillus niger. The gross structure of 1 was determined by 2D NMR studies and comparison with literature data, and the absolute stereochemistry was elucidated by chiral HPLC analysis of the hydrolysis products.

Investigation of two southern Australian marine sponges, Mycale spp., resulted in isolation of the known norsesterterpene mycaperoxide F methyl ester (5) together with a new norsesterterpene mycaperoxide G methyl ester (10) and a new norterpene ketone 11. All structures were secured by spectroscopic analysis and chemical derivatization. The absolute stereochemistry previously assigned to 5 by application of the Horeau procedure has been revised by application of the Mosher procedure.