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.
Highlights
Glucans are carbohydrate biopolymers found in the cell wall of cereals and in microorganisms such as yeasts, filamentous fungi, and algae
The carboxymethylation reaction consists of an etherification reaction that aims at replacing the hydroxyls present in the monomeric glucose units with the introduction of carboxymethyl groups
The analytical protocol used in the process of chemical derivatization of lasiodiplodan ((1-6)-β-d-glucan) was effective, promoting the production of carboxymethyl lasiodiplodan with different degrees of substitution as expected
Summary
Glucans are carbohydrate biopolymers found in the cell wall of cereals (oats and barley) and in microorganisms such as yeasts, filamentous fungi, and algae. These macromolecules belong to a heterogeneous group of glucose polymers, which consists of a linear chain composed of d-glucose units linked to each other through β-glucosidic bonds with or without branching [1]. The biological activity of β-glucans is influenced by different physicochemical parameters, including water solubility, molecular weight, primary structure, and branching. This diversity results in innumerable properties and enables a wide range of applications for such biomolecules in food, commercial biomedical, pharmaceutical, and cosmetic sectors [3]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
