**4. Conclusions**

In this study, two sulfated and pyruvated galactans were obtained from an SP-rich fraction from *C. cupressoides* seaweed. Structurally, both galactans are similar, differing only by the presence of a sulfation at position 4 in one of the SP2 units. In addition, the galactans had an immunostimulatory effect, as evidenced by the increased production of NO, ERO, and the cytokines IL-6 and TNF-<sup>α</sup>. These findings indicate that sulfation at C-4 is not essential for the immunomodulatory action of these galactans. Overall, these results sugges<sup>t</sup> that *C. cupressoides* SPs represent potential candidates for the development of new products with immunomodulatory properties of biomedical interest, with applications including the treatment of hypoimmunity or immunodeficiency conditions.

**Supplementary Materials:** The following are available online at http://www.mdpi.com/1660-3397/18/5/234/s1, Figure S1: The GPC chromatogram of SP1 and SP2 on a Sephadex G-100 column; Figure S2: 1H-NMR spectrum of SP1; Figure S3: 1H-NMR spectrum of SP2; Figure S4: 1H/1H correlation 2D-NMR spectrum (COSY) of SP1; Figure S5: 1H/1H correlation 2D-NMR spectrum (COSY) of SP2; Figure S6: 1H/13C correlation 2D-NMR spectrum (HSQCed) of SP2.

**Author Contributions:** Conceptualization, J.d.S.B. and H.A.O.R.; Data curation, C.H.F.S. and D.L.G.; Formal analysis, J.d.S.B., D.A.S., C.H.F.S., D.L.G. and A.P.S.-F.; Funding acquisition, G.L.S. and H.A.O.R.; Investigation, J.d.S.B., D.A.S., C.H.F.S. and A.P.S.; Methodology, J.d.S.B., D.A.S. and C.H.F.S.; Project administration, H.A.O.R.; Resources, G.L.S. and H.A.O.R.; Supervision, H.A.O.R.; Visualization, G.L.S.; Writing—original draft, J.d.S.B.; Writing—review & editing, H.A.O.R. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by Conselho Nacional de Desenvolvimento Científico e Tecnológico—CNPq (Edital Universal, n◦ 408369/2016-7), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior—CAPES, Programa Nacional de Cooperação Acadêmica—PROCAD (CAPES/PROCAD n◦ 2965/2014) and Ciências do Mar/CAPES (AUXPE-CIMAR-1956/2014). The APC was funded by Universidade Federal do Rio Grande do Norte.

**Acknowledgments:** The authors would like to thank the Department of Biochemistry (DBQ-UFRN) and Institute of Tropical Medicine of Rio Grande do Norte at Universidade Federal do Rio Grande do Norte for letting us use the cell culture room and flow cytometer, respectively. Also, we acknowledge at Universidade Federal do Paraná NMR Center. Hugo Alexandre O. Rocha and Guilherme L. Sassaki are CNPq fellowship-honored researchers. Diego de A. Sabry and Cynthia Haynara F. Silva received a scholarship from CAPES. This research was presented at Programa de Pós-Graduação em Ciências da Saúde at Universidade Federal do Rio Grande do Norte, as part of the doctoral thesis of Jefferson da Silva Barbosa.

**Conflicts of Interest:** The authors declare no conflict of interest.
