Antioxidant Activity of the Lignins Derived from Fluidized-Bed Fast Pyrolysis

Abstract

A challenge in recent years has been the rational use of forest and agriculture residues for the production of bio-fuel, biochemical, and other bioproducts. In this study, potentially useful compounds from pyrolytic lignins were identified by HPLC-MS/MS and untargeted metabolomics. The metabolites identified were 2-(4-allyl-2-methoxyphenoxy)-1-(4-hydroxy-3-methoxyphenyl)-1-propanol, benzyl benzoate, fisetinidol, phenyllactic acid, 2-phenylpropionic acid, 6,3′-dimethoxyflavone, and vanillin. The 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity (DPPH), trolox equivalent antioxidant capacity (TEAC), and total phenolics content (TPC) per gram of pyrolytic lignin ranged from 14 to 503 mg ascorbic acid equivalents, 35 to 277 mg trolox equivalents, and 0.42 to 50 mg gallic acid equivalents, respectively. A very significant correlation was observed between the DPPH and TPC (r = 0.8663, p ≤ 0.0001), TEAC and TPC (r = 0.8044, p ≤ 0.0001), and DPPH and TEAC (r = 0.8851, p ≤ 0.0001). The polyphenolic compounds in the pyrolytic lignins which are responsible for radical scavenging activity and antioxidant properties can be readily profiled with HPLC-MS/MS combined with untargeted metabolomics. The results also suggest that DPPH, TEAC, and TPC assays are suitable methods for the measurement of antioxidant activity in a variety of pyrolytic lignins. These data show that the pyrolytic lignins can be considered as promising sources of natural antioxidants and value-added chemicals.

Lignin from an integrated process consisting of liquid hot water and ethanol organosolv: Physicochemical and antioxidant properties

“…Among all HP-EOL samples, samples 2, 4, 6 and 8 showed the highest total phenolic content which was up to 25.6 mg GAE/g, indicating that the total phenolic content of lignin was remarkably improved by ethanol concentration (60% w/v). Qazi et al [37] reported total phenolic content values of pyrolytic Kraft lignins between 0.42 and 50 mg GAE/g. On the other hand, An et al [35] achieved up to 246.13 mg GAE/g for lignin from corn straw recovered from a residue pretreated by steam explosion and enzymatic hydrolysis, and purified using a dioxane extraction process and dichloromethane fractionation.…”

Effect of the polyphenol composition BP‑C3 on haematological and intestinal indicators of 5‑fluorouracil toxicity in mice

“…Natural plant polyphenols are promising in this regard; they protect healthy tissues, in particular decreasing production of intracellular ROS, but do not diminish the effect of chemotherapies (9). Notably, not only low-molecular weight polyphenols exhibit antioxidant efficacy, but polymeric polyphenolic compositions, such as lignin derivatives, exert it too (10).…”

Supercritical Carbon Dioxide Extraction of Lignocellulosic Bio-Oils: The Potential of Fuel Upgrading and Chemical Recovery

“…For example, it may have similarities with biochar and hydrochar, and can provide the base material for the production of adsorbents [165]. Phenolic oligomers from bio-oils were suggested as potential fuel antioxidants [105,107,108]. As sCO 2 extracts preferentially phenolic monomers, the residue is expected to be enriched in these components.…”

“…Recently, the antioxidant activity of bio-oil fractions has been studied for both pyrolysis and HTL oils derived by different biomasses [105][106][107][108]. Phenolic dimers and oligomers are suggested as the active antioxidant components, as monomers exhibited small to no antioxidant activity.…”