Chapter 7 - Chlorosulfolipids

Abstract

Chlorosulfolipids (CSLs) are unusual naturally occurring lipids with complex polychlorinated structures containing mono- or disulfate groups. The first reported CSLs were danicalipin A (2,2,11,13,15,16-hexachlorodocosane-1,14-disulfate) and related precursors from the freshwater microalga Chrysophyceae Ochromonas danica at the end of the 1960s. These planar structures were identified using elemental analysis and MS techniques, after chemical degradation. Although many CSL complexes are cytotoxic and exhibit various biological activities, CSLs from the alga have been ignored by synthetic chemists until recently because of their indeterminate stereochemistry and unclear activity. In the past decade, CSLs were isolated as cytotoxic agents from toxic Adriatic mussels in the course of Diarrheic Shellfish Poisoning research. The absolute configuration of these CSLs was elucidated using J-based configuration analysis (JBCA). The stereochemistry of CSLs in O. danica was determined using both synthetic chemical approaches and analytical chemical approaches. Further, the toxicity of natural isolated CSLs and synthetic CSLs was evaluated. This chapter is a comprehensive review of the isolation, structural determination (focusing on stereochemistry), bioactivity estimation, and roles in vivo of these naturally occurring CSLs, together with the synthetic chemical approaches for CSLs.