The occurrence of brassicasterol and epibrassicasterol in the chromophycota
1990
Gladu, P.K. | Patterson, G.W. | Wikfors, G.H. | Chitwood, D.J. | Lusby, W.R.
1. Sterols were identified from eight isolates of five species in the Chromophycota that were cultured axenically and harvested in the stationary phase. 2. Analyses were performed on four strains from the Prymnesiophyceae, two strains from the Cryptophyceae and one from the Bacillariophyceae. Most strains examined contained only one major sterol, 24-methyl-22-dehydrocholesterol. 3. Analysis by capillary GC, HPLC, and in one instance NMR, showed that the two strains provisionally identified as Isochrysis contained brassicasterol (24β-methyl-22-dehydrocholesterol); whereas, all other species examined contained primarily epibrassicasterol (24α-methyl-22-dehydrocholesterol). 4. Stigmasterol (24α-ethyl-22-dehydrocholesterol) accompanied epibrassicasterol in Pleurochrysis carterae. 5. Analyses of C-24 alkyl isomers in these algae may provide useful information concerning their taxonomic placement. 6. The occurrence of both isomers of 24-methyl-22-dehydrocholesterol in oysters is explained by the occurrence of both isomers among algae which are probably dietary sources for oysters.
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