Seasonal variation in the chemical composition of the agarophyte Pterocladia capillacea

Abstract

Seasonal variation in the chemical composition of the marine red algal species Pterocladia capillacea was studied. Except in May, the ash was characterized by a high calcium/magnesium ratio. The alga was rich in protein (34.95 %), which showed limited seasonal variation in August and November and considerable reduction in February. The presence of floridean starch in the alga was demonstrated, and the algal hydrolysates afforded galactose, glucose, glucuronic acid, xylose, and ribose. The latter sugar was attributed to the presence of algal nucleotides involved in the biosynthesis of polysaccharides. Different seasonal changes in the contents of these sugars were noted. No low-molecular carbohydrates, except trace quantities of mannitol, were found in the algal material. The presence of mannitol was attributed to epiphytic contamination. Thin-layer chromatographic analysis of the unsaponified lipid fractions revealed the presence of cholesterol, β-sitosterol, and lanosterol as constituents of the red alga in all seasons.