A new source for 4-methyl sterols in freshwater sediments : Utricularia neglecta L. (Lentibulariaceae)

Lipid analyses of several aquatic plants growing in a freshwater lake allowed us to show that Utricularia neglecta L. (Lentibulariaceae), a world-wide distributed submerged aquatic plant, is an important potential source for sedimentary 4-methyl sterols in lacustrine environments. This plant contains, besides the 4-desmethyl sterols, high proportions of 4-methyl sterols, 4α-methyl-24-ethyl-5α-cholestan-3β-ol (citrostanol) being predominant. Other 4-methyl sterols include 4α-methyl-5α-cholestan-3β-ol, 4α,24-dimethyl-5α-cholestan-3β-ol, 4α,23,24-trimethyl-5α-cholest-22-en-3β-ol (dinosterol) and 4α,23,24-trimethylcholesta-5,22-dien-3β-ol. Steroidal ketones comprising both 4-desmethyl and 4-methyl components are also present in significant amounts. The similarity of the distribution of the 4-methyl sterols in the surface sediment with those in U. neglecta L. suggests that this plant is an important source for sedimentary 4-methyl sterols