Structural features of microbial exopolysaccharides in relation to their antioxidant activity

Xylose residue (XR), after diluted acid treatment of corncob, consists of cellulose and lignin. However, structural changes of XR lignin have not been investigated comprehensively, and this has seriously hindered the efficient utilization of lignin. In this study, corncob milled wood lignin (CC MWL), and xylose residue milled wood lignin (XR MWL) were isolated according to the modified milled wood lignin (MWL) method. The structural features of two lignin fractions were thoroughly investigated via fourier transform infrared spectroscopy (FTIR), gel permeation chromatography (GPC), thermogravimetric analysis (TGA) and two dimensional nuclear magnetic resonance (2D NMR) spectroscopy techniques. XR MWL with higher yield and lower bound carbohydrate contents presented more phenolic OH contents than CC MWL due to partial cleavage of β-O-4. Furthermore, the molecular weights of XR MWL were increased, possibly because of condensation of the lignin during the xylose production. A study on antioxidant activity showed that XR lignin had better radical scavenging ability than that of 2,6-Di-tert-butyl-4-methyl-phenol (BHT) and CC MWL. The results suggested that the lignin in xylose residue, showing great antioxidant properties, has potential applications in food additives.

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Structural features and antioxidant activity of a new galactoglucan from edible mushroom Pleurotus djamor

International Journal of Biological Macromolecules ◽

10.1016/j.ijbiomac.2020.11.131 ◽

2020 ◽

Author(s):

Gajendra Nath Maity ◽

Prasenjit Maity ◽

Somanjana Khatua ◽

Krishnendu Acharya ◽

Sudipta Dalai ◽

...

Keyword(s):

Antioxidant Activity ◽

Edible Mushroom ◽

Structural Features ◽

Pleurotus Djamor

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Antioxidant Activity of Selected Phenolic Acids–Ferric Reducing Antioxidant Power Assay and QSAR Analysis of the Structural Features

Molecules ◽

10.3390/molecules25133088 ◽

2020 ◽

Vol 25 (13) ◽

pp. 3088

Author(s):

Maciej Spiegel ◽

Karina Kapusta ◽

Wojciech Kołodziejczyk ◽

Julia Saloni ◽

Beata Żbikowska ◽

...

Keyword(s):

Antioxidant Activity ◽

Phenolic Acids ◽

Density Functional ◽

Multiple Linear Regression Model ◽

Structural Features ◽

Hydroxyl Groups ◽

Antioxidant Power ◽

Qsar Analysis ◽

Structure Activity ◽

Ferric Reducing Antioxidant Power

Phenolic acids are naturally occurring compounds that are known for their antioxidant and antiradical activity. We present experimental and theoretical studies on the antioxidant potential of the set of 22 phenolic acids with different models of hydroxylation and methoxylation of aromatic rings. Ferric reducing antioxidant power assay was used to evaluate this property. 2,3-dihydroxybenzoic acid was found to be the strongest antioxidant, while mono hydroxylated and methoxylated structures had the lowest activities. A comprehensive structure–activity investigation with density functional theory methods elucidated the influence of compounds topology, resonance stabilization, and intramolecular hydrogen bonding on the exhibited activity. The key factor was found to be a presence of two or more hydroxyl groups being located in ortho or para position to each other. Finally, the quantitative structure–activity relationship approach was used to build a multiple linear regression model describing the dependence of antioxidant activity on structure of compounds, using features exclusively related to their topology. Coefficients of determination for training set and for the test set equaled 0.9918 and 0.9993 respectively, and Q2 value for leave-one-out was 0.9716. In addition, the presented model was used to predict activities of phenolic acids that haven’t been tested here experimentally.

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