Robin J. Lake

Eudistomin K sulfoxide - an antiviral sulfoxide from the New Zealand ascidian Ritterella sigillinoides

Abstract A naturally occurring sulfoxide, eudistomin K sulfoxide ( 1 ), has been isolated from the New Zealand ascidian Ritterella sigillinoides . Eudistomin K sulfoxide has antiviral properties against both DNA and RNA viruses. The semisynthesis of ( 1 ) is presented.

Isohomohalichondrin B, a new antitumour polyether macrolide from the New Zealand deep-water sponge Lissodendoryx sp.

Abstract Isohomohalichondrin B, a new structural type in the halichondrin group, has been isolated from the deep-water New Zealandsponge Lissodendoryx sp. Like some other members of the halichondrin family isohomohalichondrin B exhibited remarkable cytotoxicity against the P388 (murine leukaemia) cell line and selective cytotoxicity in the NCIs primary screen.

The stereochemistry of Eudistomins C,K,E,F AND L

Abstract Eudistomin K has been isolated from the New Zealand ascidian Ritterella sigillinoides (Brewin 1956). Nmr studies have shown that the stereochemistry of the Nue5f8O bond is 2α, not 2β as previously suggested.

Biological activity in New Zealand marine organisms

The incidence and significance of antiviral and cytotoxic activity in a New Zealand collection of marine organisms has been investigated. Several compounds with potent biological activities have been isolated and characterised.

Eudistomin K: crystal structure and absolute stereochemistry

Abstract The crystal structure of a derivative of the antiviral and antitumour compound eudistomin K 1a has been determined, confirming the proposed structure and stereochemistry. The conformation found for the oxathiazepine ring in the solid state is similar to that proposed for the solution state from nmr spectroscopic measurements.

NOESY on neurotoxins: NMR and conformational assignments of picrotoxins

Nuclear Overhauser effect spectroscopy (NOESY) gave full assignments of the 1H-NMR spectra of the picrotoxane neurotoxins tutin, hyenanchin, picrotoxinin and picrotin, as well as the solution conformations of these compounds, consistent with molecular modelling. Fully assigned 13C-NMR data are reported.

Sesquiterpenes from the marine red alga Laurencia distichophylla

Abstract A new cuparene-type sesquiterpene, isolaurenisol, has been isolated and identified from the New Zealand red alga Laurencia distichophylla. Major differences in the chemical composition of two morphologically indistinguishable samples of L. distichophylla are noted.

Okadaic Acid in New Zealand Sponges: Detection by Cytotoxicity, Protein Phosphatase Inhibition and Immunoassay techniques

Abstract Using a combination of P388 cytotoxicity testing, protein phosphatase enzyme inhibition assays and an ELISA immunoassay, okadaic acid (1), the causative agent of diarrhetic shellfish poisoning (DSP), has been found in Raspalia agminata, and detected in two other species of New Zealand sponges.