Gallic Acid-Laminarin Conjugate Is a Better Antioxidant than Sulfated or Carboxylated Laminarin
Marília Medeiros Fernandes-Negreiros,
Lucas Alighieri Neves Costa Batista,
Rony Lucas Silva Viana,
Diego Araujo Sabry,
Almino Afonso Oliveira Paiva,
Weslley Souza Paiva,
Raynara Iusk Araujo Machado,
Francimar Lopes de Sousa Junior,
Daniel de Lima Pontes,
Jussier de Oliveira Vitoriano,
Clodomiro Alves Junior,
Guilherme Lanzi Sassaki,
Hugo Alexandre Oliveira Rocha
Affiliations
Marília Medeiros Fernandes-Negreiros
Department of Biochemistry, Universidade Federal do Rio Grande do Norte, Natal, Rio Grande do Norte 59.078-970, Brazil
Lucas Alighieri Neves Costa Batista
Department of Biochemistry, Universidade Federal do Rio Grande do Norte, Natal, Rio Grande do Norte 59.078-970, Brazil
Rony Lucas Silva Viana
Department of Biochemistry, Universidade Federal do Rio Grande do Norte, Natal, Rio Grande do Norte 59.078-970, Brazil
Diego Araujo Sabry
Department of Biochemistry, Universidade Federal do Rio Grande do Norte, Natal, Rio Grande do Norte 59.078-970, Brazil
Almino Afonso Oliveira Paiva
Department of Biomedicine, Faculdade Nova Esperança (FACENE), Mossoró 59.628-000, Brazil
Weslley Souza Paiva
Department of Biochemistry, Universidade Federal do Rio Grande do Norte, Natal, Rio Grande do Norte 59.078-970, Brazil
Raynara Iusk Araujo Machado
Department of Biochemistry, Universidade Federal do Rio Grande do Norte, Natal, Rio Grande do Norte 59.078-970, Brazil
Francimar Lopes de Sousa Junior
Laboratório de Química de Coordenação e Polímeros-LQCPol, Instituto de Química, Universidade Federal do Rio Grande do Norte—UFRN, Natal-RN 59.078-970, Brazil
Daniel de Lima Pontes
Laboratório de Química de Coordenação e Polímeros-LQCPol, Instituto de Química, Universidade Federal do Rio Grande do Norte—UFRN, Natal-RN 59.078-970, Brazil
Jussier de Oliveira Vitoriano
Centro Integrado de Inovação Tecnológica do Semiárido (CiTED), Universidade Federal Rural do Semi-Árido, Mossoró 59.625-900, Brazil
Clodomiro Alves Junior
Centro Integrado de Inovação Tecnológica do Semiárido (CiTED), Universidade Federal Rural do Semi-Árido, Mossoró 59.625-900, Brazil
Guilherme Lanzi Sassaki
Departament of Biochemistry, Federal University of Parana, Curitiba 81.531-980, Brazil
Hugo Alexandre Oliveira Rocha
Department of Biochemistry, Universidade Federal do Rio Grande do Norte, Natal, Rio Grande do Norte 59.078-970, Brazil
A 12.4 kDa laminarin (LM) composed of β(1→3)-glucan with β(1→6)-branches was extracted from brown seaweed Lobophora variegata and modified via carboxylation using dielectric barrier discharge (LMC), conjugation with gallic acid (LMG), and sulfation (LMS). Analyses of the chemical composition of LMC, LMG, and LMS yielded 11.7% carboxyl groups, 1.5% gallic acid, and 1.4% sulfate content, respectively. Antioxidant activities of native and modified laminarins were assessed using six different in vitro methods. Sulfation stopped the antioxidant activities of LM. On the other hand, carboxylation improved cooper chelation (1.2 times). LMG was found to be a more efficient antioxidant agent than LM in terms of copper chelation (1.3 times), reducing power (1.3 times), and total antioxidant capacity (80 times). Gallic acid conjugation was further confirmed using Fourier transform infrared spectroscopy (FT-IR) and one- and two-dimensional NMR spectroscopy analyses. LMG also did not induce cell death or affect the cell cycle of Madin–Darby canine kidney (MDCK) cells. On the contrary, LMG protected MDCK cells from H2O2-induced oxidative damage. Taken together, these results show that LMG has the potent antioxidant capacity, and, therefore, potential applications in pharmacological and functional food products.
