RESUMO
An original sodium alginate from Tunisian seaweed (Cystoseira barbata) was purified and characterized by circular dichroism (CD) and ATR-FTIR spectroscopies. ATR-FTIR spectrum of C. barbata sodium alginate (CBSA) showed the characteristic bands of mannuronic (M) and guluronic acids (G). The M/G ratio was estimated by CD (M/G = 0.59) indicating that CBSA was composed of 37% mannuronic acid and 63% guluronic acid. The analysis of viscosity of CBSA showed evidence of pseudoplastic fluid behaviour. The emulsifying capacity of CBSA was evaluated at different concentrations (0.25-3%), temperatures (25-100 °C) and pH (3.0-11.0). Compared to most commercial emulsifiers, the emulsion formulated by CBSA was found to be less sensitive to temperature changes and more stable at acidic pH. CBSA was examined for antioxidant properties using various antioxidant assays. CBSA exhibited important DPPH radical-scavenging activity (74% inhibition at a concentration of 0.5 mg/ml) and considerable ferric reducing potential. Effective hydroxyl-radical scavenging activity (82% at a concentration of 5 mg/ml) and potent protection activity against DNA breakage were also recorded for CBSA. However, in the linoleate-ß-carotene system, CBSA exerted moderate antioxidant activity (60% at a concentration of 1.5 mg/ml). Therefore, CBSA can be used as a natural ingredient in food industry or in the pharmaceutical field.
Assuntos
Alginatos/química , Alginatos/isolamento & purificação , Antioxidantes/química , Antioxidantes/isolamento & purificação , Fenômenos Químicos , Phaeophyceae/química , Alga Marinha/química , Alginatos/farmacologia , Antioxidantes/farmacologia , Compostos de Bifenilo/química , Dicroísmo Circular , Quebras de DNA de Cadeia Simples/efeitos dos fármacos , Emulsões/química , Sequestradores de Radicais Livres/química , Ácido Glucurônico/química , Ácido Glucurônico/isolamento & purificação , Ácido Glucurônico/farmacologia , Ácidos Hexurônicos/química , Ácidos Hexurônicos/isolamento & purificação , Ácidos Hexurônicos/farmacologia , Concentração de Íons de Hidrogênio , Radical Hidroxila/química , Peso Molecular , Oxirredução , Picratos/química , Reologia , Espectroscopia de Infravermelho com Transformada de Fourier , Tunísia , Viscosidade , beta Caroteno/químicaRESUMO
The methanolic and aqueous extracts of Pituranthos scoparius (Coss. & Dur.) Benth. & Hook. (Apiaceae) have been analyzed and fifteen metabolites were identified: two cinnamic acids (5-O-caffeoyl quinic acid and 5-feruloyl quinic acid), and thirteen known flavonoids (vicenin-2, six quercetin and six isorhamnetin O-glycosylated derivatives). 5-O-caffeoylquinic acid was the main component, while, of the flavonoids, the isorhamnetin derivatives were present to a greater extent.
