Sterols in red algae (Rhodophyceae): Variation in the desmosterol content of dulse ( Rhodymenia palmata)

Abstract

1. 1. Desmosterol ranged from 30·6 to 97·2 per cent and averaged 73·6 per cent of the total sterol in twenty-three samples of dulse collected during the months of June–November. 2. 2. Cholesterol was the second principal sterol ranging from 2·1 to 49·2 per cent and averaging 13·0 per cent. 3. 3. Twelve minor sterols were detected in various samples and seven were identified by GLC. 4. 4. The sterol compositions were variable and did not depend on the location or time of collection. 5. 5. Average total lipid, unsaponifiable lipid and sterol contents were highest in samples taken during June, July and August. Sterol content ranged from 0·005 to 0·019 per cent and averaged 0·012 per cent of the dry weight of dulse. 6. 6. Cholesterol was the principal sterol in three other red algae, Ptilota serrata, Furcellaria fastigiata and Phyllophora membranifolia.