Tropical marine macroalgae as potential sources of nutritionally important PUFAs

The lipid and fatty acid compositions of 27 tropical macroalgae belonging to the three phyla, Chlorophyta, Phaeophyta and Rhodophyta, were studied from a nutritional and chemotaxonomic perspective. The lipid content varied widely among the species and ranged from 0.57% to 3.5% on a dry weight basis (p ⩽ 0.01). Chlorophyta members showed higher C18PUFAs contents than did C20 PUFAs while for Rhodophyta the trend was opposite. The Phaeophyta members displayed a profile of C18PUFAs similar to that of Chlorophyta and of C20PUFAs to that of Rhodophyta. Both Phaeophyta and Rhodophyta species were rich in arachadonic acid (AA) and eicosopentaenoic acid (EPA) and Ulvales in docosahexaenoic acid (DHA) content. Most of the species studied had a nutritionally beneficial n6/n3 ratio (0.61–5.15:1). Further, the principal component analysis clearly segregated the three phyla by their FA composition and hierarchical cluster analysis altogether classified them into six distinct groups, suggesting that FAs can be used as a tool for chemotaxonomic studies.