STEROLS OF CHLORELLA. I. THE NATURALLY OCCURRING STEROLS OF CHLORELLA VULGARIS, C. ELLIPSOIDEA, AND C. SACCHAROPHILA12

Abstract

The characteristics of the sterols naturally occurring in three species of Chlorella were examined. The algae were grown heterotrophically on glucose. Sterols were extracted and isolated from the lipid fraction and were characterized by means of chemical and physical tests. Chlorella vulgaris contained three sterols. Only the principal one, chondrillasterol, was identified. Chondrillasterol has been isolated previously from the genus Scenedesmus. Chlorella ellipsoidea and Chlorella saccharophila were found to contain sterols with β-oriented alkyl groups at C-24 in contrast to the α-oriented groups commonly found in higher plants. Poriferasterol was identified as the principal sterol of both algae. Clionasterol and 22-dihydrobrassicasterol were identified as the two secondary sterols present. None of these sterols have previously been reported to occur in plants. The isolation of 22-dihydrobrassicasterol has not been previously reported from any natural source.