The Distribution of Asterosaponins, Polyhydroxysteroids and Related Glycosides in Different Body Components of the Far Eastern Starfish Lethasterias fusca.

Roman S Popov,Timofey V Malyarenko,Alla A Kicha,Natalia V Ivanchina,Pavel S Dmitrenok,Boris B Grebnev,Valentin A Stonik

doi:10.3390/md17090523

Abstract

Glycoconjugated and other polar steroids of starfish have unique chemical structures and show a broad spectrum of biological activities. However, their biological functions remain not well established. Possible biological roles of these metabolites might be indicated by the studies on their distribution in the organism–producer. In order to investigate the localization of polar steroids in body components of the Far Eastern starfish Lethasterias fusca, chemical constituents of body walls, gonads, stomach, pyloric caeca, and coelomic fluid were studied by nanoflow liquid chromatography/mass spectrometry with captive spray ionization (nLC/CSI–QTOF–MS). It has been shown that the levels of polar steroids in the studied body components are qualitatively and quantitatively different. Generally, the obtained data confirmed earlier made assumptions about the digestive function of polyhydroxysteroids and protective role of asterosaponins. The highest level of polar steroids was found in the stomach. Asterosaponins were found in all body components, the main portion of free polyhydroxysteroids and related glycosides were located in the pyloric caeca. In addition, a great inter-individual variability was found in the content of most polar steroids, which may be associated with the peculiarities in their individual physiologic status.

Highlights

Starfish are characterized by a high content of polar, frequently glycoconjugated steroids
We describe the application of nLC/CSI–QTOF–MS for the profiling of purified fractions of polar steroids from body walls, coelomic fluid, gonads, stomach, and pyloric caeca to establish the content of these metabolites in different body components of the starfish L. fusca
We have studied polar steroid metabolites of the starfish L. fusca by nanoflow liquid chromatography coupled with a captive spray ionization time-of-flight tandem mass spectrometer

Summary

Introduction

Starfish are characterized by a high content of polar, frequently glycoconjugated steroids. Polar steroid compounds from starfish have put together an important class of biologically active marine metabolites, including steroids bearing four to nine hydroxyl groups, related polyhydroxysteroid mono-, bi- and triosides, and oligoglycosides known as asterosaponins [1,2,3,4,5,6]. Structural diversity of these metabolites is significant. The side chains of asterosaponin aglycones and their oligosaccharide fragments show significant structural diversity [1,2,3,4,5,6]

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Conclusion