Purification, structural characterization and antioxidant activity of a new arabinogalactan from Dorema ammoniacum gum.
Int J Biol Macromol
; 194: 1019-1028, 2022 Jan 01.
Article
em En
| MEDLINE
| ID: mdl-34848241
ABSTRACT
Gum ammoniacum is a polymer obtained from Dorema ammoniacum and its medicinal use was already known to the ancient times. In this study, a new D. ammoniacum carbohydrate (DAC-1) with a molecular weight of 27.1 kDa was extracted by hot water and then purified on DEAE-52-cellulose and Sephadex G-100 columns. The structural features of DAC-1 were investigated by partial acid hydrolysis, fourier-transform infrared spectroscopy (FT-IR), methylation, gas chromatography-mass spectrometry (GC-MS), gas chromatography-flame ionization detection (GC-FID), and 1D and 2D nuclear magnetic resonance spectroscopy (1D & 2D NMR). The results indicated that DAC-1 was an arabinogalactan including galactose, arabinose, rhamnose, glucuronic acid and 4-O-methyl-ß-d-glucopyranosyl uronic acid (meGlcpA) with a relative percentage of 44.63%, 23.30%, 13.46%. 12.47%, and 6.14%. The structure units of DAC-1 were elucidated as 3,1)-ß-D-Galp-(6 â 1)-ß-D-Galp-(3,6 â containing four branch chains of â1,6)-ß-D-Galp-(3 â 1)-α-L-Araf-(5 â 1)-ß-D-GlcpA-(4 â 1)-α-L-Rhap-T (two times), â1,6)-ß-D-Galp-(3â1)-ß-D-Galp-(3 â 1)-ß-D-Galp-(3 â 1)-ß-D-Galp-(3 â 1)-α-L-Araf-T and â1,6)-ß-D-Galp-(3 â 1)-α-L-Araf-(5 â 1)-ß-D-meGlcpA-T. X-ray diffraction (XRD) pattern indicated a semi-crystalline structure. Thermal behavior of the polysaccharide was evaluated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) and revealed temperatures higher than 200 °C as dominant region of weight loss. DAC-1 showed acceptable antioxidant activity when analyzed by DPPH, ABTS, FRAP, and OH radical removal methods.
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Base de dados:
MEDLINE
Assunto principal:
Ferula
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Galactanos
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Antioxidantes
Idioma:
En
Ano de publicação:
2022
Tipo de documento:
Article