The Distribution of Sterols and Stanols in the TunicateCiona Intestinalis

Abstract

INTRODUCTIONUntil recently saturated sterols – stands – were not thought to play an active biochemical or physiological role in organisms. They were generally considered to be diagenetic products of the microbiological reduction of the common natural product Δ5sterols and as such have been reported in sediments (e.g. Gaskell & Eglinton, 1975).Prior to the regular use of capillary gas liquid chromatographic (GLC) and gas chromatographic-mass spectrometric (GC-MS) techniques the majority of sterol analyses had been performed on packed column GLC. It is now well known that in the analysis of some of the complex mixtures of sterols which commonly occur in the marine environment, the use of packed column GLC techniques alone is an inadequate procedure (e.g. Ballantine; Roberts & Morris, 1976; Ballantineet al.1977). Certainly complete resolution of the sterol-stanol pairs cannot normally be achieved on packed columns and identification of the components within each peak has to be made by multiple mass spectral scans across each peak (Ballantineet al.1976). With the advent of techniques with better resolving powers, significant amounts of natural product stands have been found in a wide spectrum of phyla including molluscs, sponges coelenterates, echinoderms, annelids and tunicates (Morris & Culkin, 1977 and references therein; Ballantineet al.1976; Ballantine, Lavis & Morris, 1979, 1981; Voogt, 1976; Ballantineet al.1977; Ballantineet al.1978; Guptaet al.1979). In some instances the stanols have been found to account for over 50% of the animals component sterols.As the sterol profile of marine invertebrates becomes better understood it is clear that stanolsareimportant biochemical constituents of many of these organisms; but little is known of their significance in any biochemical or physiological role.