Sterol and fatty acid compositions of seagrasses from Magnetic Island, North Queensland

Fresh leaves of seven species of tropical seagrasses, collected from Magnetic Island, north Queensland, were analysed for sterol and fatty acid composition. The species examined were Cymodocea serrulata, Enhalus acoroides, Halodule uninervis, Halophila ovalis, Halophila ovata, Halophila spinulosa and Thalassia hemprichii.Samples were extracted with CHC13-MeOH (1:1). Sterols and fatty acid methyl esters were prepared from the extracts. Sterols (as the methyl ethers) and fatty acid methyl esters were analysed by GLC.Fatty acids and sterols were identified by their mass spectra and by co-chromatography with standards where available. This research was undertaken to determine if chemical markers were present in seagrass leaves, which would allow seagrass derived material to be traced through coastal ecosystems. Variations in sterol and fatty acid composition were examined for potential chemotaxonomic significance.