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Immunostimulatory and antioxidant activities of a lignin isolated from Conocarpus erectus leaves

2020; Elsevier BV; Volume: 150; Linguagem: Inglês

10.1016/j.ijbiomac.2020.02.052

1879-0003

Dayane Kelly Dias do Nascimento Santos, Bárbara Rafaela da Silva Barros, Lethícia Maria de Souza Aguiar, Iranildo José da Cruz Filho, Virgínia Maria Barros de Lorena, Cristiane Moutinho Lagos de Melo, Thiago Henrique Napoleão,

Leaf Properties and Growth Measurement

In this work, we investigated the antioxidant and immunomodulatory activities of a lignin isolated from Conocarpus erectus leaves. The lignin was characterized by FTIR, 1H NMR, 13C NMR and gel permeation chromatography analysis as well as ultraviolet/visible absorption spectra. The lignin was evaluated for total antioxidant activity (TAA), DPPH and ABTS+ scavenging abilities, and by a lipid peroxidation inhibition assay. Immunomodulatory activity of the lignin (10 μg/mL) on human peripheral blood mononuclear cells (PBMCs) was determined. The C. erectus lignin was found to be of the guaiacyl-syringyl-p-hydroxyphenyl (G-S-H) type, with an average molecular weight of 2709 Da (polydispersity index: 2.1). It showed low TAA (17.92%) and moderate antioxidant activity against DPPH and ABTS+ (IC50: 231.16 and 356.03 μg/mL, respectively). It also inhibited lipid peroxidation by 42.14%. The lignin promoted an increase in mitochondrial ROS levels as well as cytosolic Ca2+ in PBMCs. In addition, it promoted the differentiation and activation of CD8+ T lymphocytes, differentiation of CD14+ monocytes, and stimulated the release of nitric oxide and cytokines, mainly those linked to a Th1 response. The results showed that the C. erectus lignin may be used in future studies in which the modulation of the immune response is a key factor.