Blends de polissacarídeos sulfatados e picolinato de cromo: produção e avaliação de sua atividade antioxidante

• Ano de defesa: 2022
• Autor(a) principal: Morais, Yara Campanelli de
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal do Rio Grande do Norte; Brasil; UFRN; PROGRAMA DE PÓS-GRADUAÇÃO EM BIOQUÍMICA E BIOLOGIA MOLECULAR
• Palavras-chave em Português: Estresse oxidativo; Nutracêutico; Gracilaria birdiae; Micronúcleo; Agarana; CNPQ::CIENCIAS BIOLOGICAS
• Link de acesso: https://repositorio.ufrn.br/handle/123456789/51337

The red seaweed Gracilaria birdiae (Gb) is cultivated and used as food in Northeast Brazil and its sulfated polysaccharide (agaran), called SPGb, is said to contain several properties of academic interest, including as an antioxidant agent. Chromium picolinate (ChrPic) is a bioinorganic compound with anti-inflammatory capacity. The objective was to produce blends containing SPGb and ChrPic and evaluate them as better antioxidant agents, since blends correspond to the association of compounds whose objective is to improve their activity/efficiency, in relation to isolated producers. Regarding the properties attributed to SPGb and ChrPic, there is no record of blends uniting them. ChrPic was purchased commercially and SPGb obtained from seaweed, after an extraction technique through exposure to ultrasound waves, basic medium and proteolysis. The identification of SPGb was confirmed by chemical analysis and nuclear magnetic resonance (1H1D and HSQC). ChrPic (from 0.5 to 2.0 mg/mL) did not show copper or iron chelating activity, whereas SPGb (2.0 mg/mL) showed activity of 70 and 73% for these tests, respectively. ChrPic (1.0 mg/mL) showed approximately 80% and 100% scavenging activity for superoxide and hydroxyl radicals, respectively, while SPGb (2.0 mg/mL) did not show this activity. Five blends were produced (B1; B2; B3; B4; B5) whose antioxidant activity was evaluated and data indicated B5 as the blend with the most potent antioxidant agent. Micronucleus test (CBMN) demonstrated that B5 does not have genotoxic activity, as well as for cytotoxicity in murine fibroblasts (3T3) and Chinese hamster ovary cells (CHO-K1), B5 and SPGb also did not show genotoxic activity, ChrPic (0.2 mg/mL) decreased the ability of cells to reduce MTT by 30%, but all samples protected cells by more than 70%. When 3T3 cells were exposed to hydrogen peroxide (H2O2) (0.6 mM) they showed about 50% of the ability to reduce MTT compared to cells not exposed to peroxide, so three different moments of H2O2 presence were tested. In the first moment, cells were incubated with peroxide and subsequently exposed to SPGb, ChrPic or B5 for 24 hours. In this case, SPGb was not effective in protecting cells from peroxide, while cells exposed to ChrPic (0.025; 0.05 and 0.1 mg/mL) and B5 (0.05 mg/mL) reduced MTT by 100%. In the second moment, the samples were placed in the cells along with hydrogen peroxide and it was noticed that a reduction of less than 30% of MTT was observed in the presence of SPGb, of up to 55% in the presence of ChrPic, and of 96% in the presence of B5 (0.05 mg/mL). In the third moment, the cells were exposed to SPGb, ChrPic or B5 for 24 h, and subsequently to H2O2 (0.6 mM). It was verified that the presence of SPGb was unable to prevent the decrease in the capacity of the cells in reducing MTT, while cells exposed to ChrPic and B5, at all concentrations, reduced MTT by 100%. Blend B5 is a potential antioxidant agent and more in vivo studies are needed to confirm its nutraceutical activity.