Three new glycolipids with cytolytic activity from cultured marine dinoflagellate Heterocapsa circularisquama

Abstract

A monogalactosyl monoacylglycerol 1 and two digalactosyl monoacylglycerols 2 and 3 were isolated from a cultured marine dinoflagellate Heterocapsa circularisquama along with known (2S)-1-O-6,9,12,15-octadecatetraenoyl-3-O-β-D-galactopyranosyl]-sn-glycerol (4). On the basis of spectral analysis, the glycolipid 1 was characterised as (2S)-1-O-3,6,9,12,15-octadecapentaenoyl-3-O-β-D-galactopyranosyl]-sn-glycerol. The glycolipids 2 and 3 were characterised as (2S)-1-O-3,6,9,12,15-octadecapentaenoyl-3-O-[α-D-galactopyranosyl-(1′′′ → 6′′)-O-β-D-galactopyranosyl]-sn-glycerol and (2S)-1-O-6,9,12,15-octadecatetraenoyl-3-O-[α-D-galactopyranosyl-(1′′′ → 6′′)-O-β-D-galactopyranosyl]-sn-glycerol, respectively. The isolated monoacylglycerols 1–4 showed cytolytic activity towards heart and gill cells of oyster.

Keywords:

• Dinoflagellate
• Heterocapsa circularisquama
• Monogalactosyl monoacylglycerol
• Digalactosyl monoacylglycerol
• Cytolytic activity

Acknowledgements

The authors are grateful to Dr S. Kojima, Graduate School of Science, Hiroshima University, for their valuable advice and pre-reading the manuscript and Dr H. Takayama, Hiroshima Prefecture Fisheries and Marine Technology Center, for generously providing the dinoflagellate, Heterocapsa circularisquama. Spectral measurements were made at the Hiroshima Prefectural Research Institute for Science and Technology (NMR) and the Instrument Center for Chemical Analysis, Hiroshima University (FABMS). This work was supported in part by a Grant-in-Aid for Scientific Research (Nos. 11558077 and 13024256) from the Japan Society for the Promotion of Science and by the Regional Science Promoter Program of Hiroshima Prefecture.