Seasonal Chemical Screening and Biological Activity of Undaria pinnatifida (Harvey) Suringar (Alariaceae, Laminariales, Phaeophyta), collected at Golfo San Jorge (Patagonia Argentina).

The alga Undaria pinnatifida is able to synthesize a great variety of bioactive metabolites of pharmaceutical and other industrial interest. However, this species has not yet been comprehensively studied in the Golfo San Jorge region (Chubut, Patagonia Argentina). Thus, in the present study, U. pinnatifida was collected at Golfo San Jorge, seasonally extracted and the chemical profile and biological activity evaluated by different techniques. The results showed that U. pinnatifida fundamentally biosynthesizes phenolic acids (caffeic and ferulic acids), flavonols and flavanol glycosides (quercetin, cacticin, quercitrin), carbohydrates, tannins, lipids, saponins, quinones, steroids, triterpenes and cardiotonic glycosides (of the k-strophanthoside, sciloriside, adynerin and convalatoxin types), with differences according to the season. The extracts also showed moderate antioxidant activity by the DPPH method and outstanding cytotoxic activity by the Artemia salina test. Based on the results obtained, U. pinnatifida can be considered as a potential source of bioactive molecules. Variations in the metabolites were observed throughout the seasons; particularly in the winter season, flavonoids were present in hexane and chloroform extracts, but not in methanol; tannins and other phenolic derivatives in the three winter extracts. This shows the importance of conducting seasonal studies to determine the best season for collection based on the metabolites to be studied. [ABSTRACT FROM AUTHOR]