Antioxidant and antitumor potential of wild and IMTA-cultivated Osmundea pinnatifida

Osmundea pinnatifida is a red edible seaweed known as pepper dulse. O. pinnatifida was cultivated in the farm of ALGAplus (Ilhavo, Portugal). This farm is integrated with a seabream and seabass commercial aquaculture and uses the nutrient-enriched water resultant from the fish production as its cultivation medium in the integrated multi-trophic aquaculture (IMTA) manner. Wild and IMTA-cultivated samples of O. pinnatifida were screened for antioxidant and antitumor activities. The antioxidant capacity of solvent extracts from wild and IMTA cultivated samples was assessed in two methods (2,2-diphenyl-1-picrylhydrazyl (DPPH) and oxygen radical absorbance capacity (ORAC)), and their total phenolic contents (TPC) were estimated. Antitumor activity was evaluated in three different tumor cell lines (HepG-2, MCF-7, and SH-SY5Y) through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Among the solvents used for extraction, dichloromethane was the most effective to extract phenolic compounds and presented higher ORAC. A significant correlation was found between TPC and ORAC, which was also sustained by the principal components analysis (PCA). Dichloromethane extracts induced a cytostatic effect on MCF-7 cells and showed weak cytotoxicity to SH-SY5Y cells and weak impact on cell proliferation. Overall, there were no statistically significant differences in the biological activities shown by the wild and IMTA-cultivated samples. Hence, O. pinnatifida can be obtained in an economical and environmentally sustainable way through IMTA, maintaining bioactive properties in a high potential for further nutraceutical purposes.