Table of Contents

Abstract: The extract of the sea hare, Aplysia kurodai, showed cytotoxicity against HeLa cells and antibacterial activity against Staphylococcus aureus. Bioassay-guided purification afforded four active compounds, which were identified to be laurinterol, laurinterol acetate, debromolaurinterol, and debromolaurinterol acetate by spectroscopic analysis. Although the acetates were derived from laurinterol and debromolaurinterol before, this is the first isolation of the acetates from natural sources.

Abstract: A new oxazole-containing proteasome inhibitor, secomycalolide A, together with known mycalolide A and 30-hydroxymycalolide A, was isolated from a marine sponge of the genus Mycale. They showed proteasome inhibitory activities with IC₅₀ values of 11-45 μg/mL.

Abstract: Reverse chemical proteomics combines affinity chromatography with phage display and promises to be a powerful new platform technology for the isolation of natural product receptors, facilitating the drug discovery process by rapidly linking biologically active small molecules to their cellular receptors and the receptors’ genes. In this paper we review chemical proteomics and reverse chemical proteomics and show how these techniques can add value to natural products research. We also report on techniques for the derivatisation of polystyrene microtitre plates with cleavable linkers and marine natural products that can be used in chemical proteomics or reverse chemical proteomics. Specifically, we have derivatised polystyrene with palau’amine and used reverse chemical proteomics to try and isolate the human receptors for this potent anticancer marine drug.

Abstract: Verrucarin A is an inhibitor of protein synthesis. In this study, we examined the inhibitory action of verrucarin A on signal molecules. Verrucarin A partially inhibited the IL-8 production of a PMA-stimulated promyelocytic leukemia cell line (HL-60 cells), and the effect was related to the inhibition of NF-κB activation at noncytotoxic concentrations. Moreover, the inhibition of mitogen activated protein (MAP) kinase by verrucarin A was especially strong with p38- and JNK-phosphorylation. The findings show a new action of verrucarin A, and it is expected that this action relaxes the signal activation in response to stress.

Abstract: Publisher's Note added on 9 October 2006 : Pages 74-77 are taken as blank pages.