Fungal Exocellular (1-6)-β-d-glucan: Carboxymethylation, Characterization, and Antioxidant Activity

Abstract

Exocellular (1→6)-β-d-glucan (lasiodiplodan) produced by the fungus Lasiodiplodia theobromae MMPI was derivatized by carboxymethylation using different concentrations of a derivatizing agent. Lasiodiplodan was derivatized by carboxymethylation in an attempt to increase its solubility and enhance its biological activities. Carboxymethylglucans with degrees of substitution (DS) of 0.32, 0.47, 0.51, 0.58, and 0.68 were produced and characterized. FTIR analysis showed a band of strong intensity at 1600 cm−1 and an absorption band at 1421 cm−1, resulting from asymmetric and symmetrical stretching vibrations, respectively, of the carboxymethyl group COO- in the carboxymethylated samples. Thermal analysis showed that native lasiodiplodan (LN) and carboxymethylated derivatives (LC) exhibited thermal stability up to 200–210 °C. X-ray diffractometry demonstrated that both native and carboxymethylated lasiodiplodan presented predominantly an amorphous nature. Scanning electron microscopy revealed that carboxymethylation promoted morphological changes in the biopolymer and increased porosity, and alveolar structures were observed along the surface. The introduction of carboxymethyl groups in the macromolecule promoted increased solubility and potentiated the hydroxyl radical-scavenging activity, suggesting a correlation between degree of substitution and antioxidant activity.

Gallic Acid-Dextran Conjugate: Green Synthesis of a Novel Antioxidant Molecule

“…The introduction of chemical groups into the polysaccharide molecules may contribute to the strengthening or weakening of the hydrogen bond dissociation energy. Therefore, hydrogen donation capacity of the polysaccharide may be increased or decreased and may consequently affect its antioxidant potential [44].…”

Effects of Medicinal Fungi-Derived β-Glucan on Tumor Progression

“…From the computer models we can assume a left- or right-handed triple helix configuration in water [ 42 ]. In fungal glucans, some chemical modifications, such as carboxymethylation, result in improvements of biological activity, particularly in antioxidant activity [ 51 ].…”

Produção e caracterização do exopolissacarídeo lasiodiplodana por >i<Lasiodiplodia theobromae>/i< a partir de hidrolisado celulósico do bagaço de cana-de-açúcar

“…A solubilidade do EPS obtido da suplementação com farelo de soja foi 4,53% (4,53 mg/100 mL), enquanto a suplementação com farelo de arroz foi 16,81% (16,81 mg/100 mL). Theis et al (2019) obtiveram resultados de solubilidade semelhantes (4,02%) com LAS nativa produzida a partir de glicose em relação à LAS obtida com suplementação de soja.…”

“…Fonte: Autoria própria O perfil difractográfico das amostras de LAS apresentam uma matriz amorfa, como demonstraram previamente vários trabalhos (CALEGARY et al, 2017;THEIS et al, 2017;LUNA et al, 2018;THEIS et al, 2019). A região angular de difração, aproximadamente entre 7,15 e 17,5° (2θ) de ambas amostras de LAS, demonstraram um pico intenso e amplo, na forma de ombro, e a partir de 17,5° (2θ) não são apresentados mais picos, sendo EPS completamente amorfos.…”

“…A banda de 1.650 cm-1 presente na região corresponde ao anel de glicose, enquanto as vibrações simétricas de ligações C-O-C, que são características dos carboidratos, têm absorção em 1075 cm-1 (KAGIMURA et al, 2015b). Na região de 890 cm-1 existe uma banda com baixa intensidade das ligações glicosídicas, atribuída à conformação β de LAS, conforme o descrito anteriormente por estudos de LAS na região infravermelho (VASCONCELOS et al, 2013;KAGIMURA et al, 2015a;CALEGARY et al, 2017;THEIS et al, 2017;LUNA et al, 2018;THEIS et al, 2019).…”