Back to Search Start Over

Antioxidant Activity and Chemical Characteristics of Supercritical CO2 and Water Extracts from Willow and Poplar

Authors :
Marek Adamczak
Bartosz Brzozowski
Wiesław Wiczkowski
Mateusz Ostolski
Source :
Molecules, Volume 26, Issue 3, Molecules, Vol 26, Iss 545, p 545 (2021)
Publication Year :
2021
Publisher :
Multidisciplinary Digital Publishing Institute, 2021.

Abstract

Renewable feedstock from perennial industrial crops, including those cultivated on marginal land in a short-rotation coppice system, could be an important contribution to the bioeconomy. The majority of data available on the topic are limited to the production of bioenergy from this type of biomass. According to the concept of bioeconomy, biomass-based bioproducts have priority over energy production. This paper characterizes the chemical composition and antioxidant activity of extracts from bark (b), wood (w) or a mixture of bark and wood (b + w) from Salix purpurea, Salix viminalis and Populus nigra obtained using supercritical carbon dioxide (scCO2), scCO2 and water (1%, w/w) or only water. Generally, a high concentration of polyphenols was obtained after extraction with scCO2 and water, while the lowest concentration was found in extracts obtained with scCO2. The highest concentration of polyphenols (p &lt<br />0.05) was obtained in an extract from P. nigra (b) (502.62 &plusmn<br />9.86 mg GAE/g dry matter (d.m.)) after extraction with scCO2 and water, whereas the lowest polyphenol concentration was observed in an scCO2 extract from S. purpurea (b) (6.02 &plusmn<br />0.13 mg GAE/g d.m.). The flavonoids were effectively separated by extraction with scCO2 (0.88&ndash<br />18.37 mg QE/g d.m.). A positive linear relationship between the antioxidant activity determined by DPPH and ABTS assays and the concentration of polyphenols was demonstrated, R2 = 0.8377 and R2 = 0.9568, respectively. It is most probable that the concentration of flavonoids, rather than the concentration of polyphenols, determines the chelating activity of Fe2+. The Fe2+-chelating activity of scCO2 extracts ranged from 75.11% (EC50 = 5.41 mg/cm3, S. purpurea, b + w) to 99.43% (EC50 = 0.85 mg/cm3, P. nigra, b + w). The lowest chelating activity was demonstrated by the extracts obtained with scCO2 and water (maximum 26.36%, S. purpurea, b + w). In extracts obtained with scCO2 and water, p-hydroxybenzoic acid (210&ndash<br />428 &micro<br />g/g), p-coumaric acid (56&ndash<br />281 &micro<br />g/g), saligenin (142&ndash<br />300 &micro<br />g/g) and salicortin (16&ndash<br />164 &micro<br />g/g) were the dominant polyphenols. All of these chemical compounds occurred mainly in the free form. The S. purpurea, S. viminalis and P. nigra biomass proved to be an attractive source of biologically active compounds for various possible applications in food, drugs or cosmetics. These compounds could be extracted using an environmentally friendly method with scCO2 and water as a co-solvent.

Details

Language :
English
ISSN :
14203049
Database :
OpenAIRE
Journal :
Molecules
Accession number :
edsair.doi.dedup.....6016217086c6a90537c91c548cd5cbdf
Full Text :
https://doi.org/10.3390/molecules26030545