Phytochemical variations of green algae, Ulva lactuca, and brown algae, Sargassum vulgare, in winter and spring seasons

The natural products of seaweeds have been taken into consideration due to their application in various fields of medicine, nutrition, and agriculture in the world. Recent research has shown that marine metabolites can form the future of the bioeconomy. There are many populations of Ulva and Sargassum algae on the southern coasts of Iran, and therefore, in this research, the populations of U. lactuca and S. vulgare were collected from the shores of Bushehr, and their photosynthetic pigments, soluble carbohydrates, total protein and compounds in essential oils were investigated in the winter and spring seasons. The results showed that S. vulgare in spring and U. lactuca in winter had the highest amount of chlorophylls and total carotenoids. The amount of soluble carbohydrates in U. lactuca significantly increased in spring compared to winter. The amount of total protein in both species significantly increased in winter compared to spring. The main components of the essential oils of both species included alkane hydrocarbons, which often had a higher abundance percentage in winter. In spring, fatty acids and aromatic compounds with phenyl ring(s) were observed in the essential oils of these species. Considering the changes in the content of metabolites in these species along with seasonal changes, the present results can be effective in the targeted selection of algal species and the appropriate harvesting time for special applications.