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

Sohail Qazi,Franco Berruti,Dongbing Li,Cedric Briens,Mamdouh Abou-Zaid

doi:10.3390/molecules22030372

Sohail Qazi, Franco Berruti + Show 3 more

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https://doi.org/10.3390/molecules22030372

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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.

Highlights

Renewable plant biomass holds an eco-friendly and promising future in the years ahead, since it is an effective alternative source of renewable energy in the current scenario of depleting oil reserves, global warming, and growing environmental concerns
The current study provides a first report on the HPLC-MS/MS combined with untargeted metabolomic analysis of pyrolytic lignins
The HPLC-MS/MS and untargeted metabolomics revealed that pyrolytic lignins have high compound amounts and high antioxidant activity in contrast to non-pyrolytic lignins

Summary

Introduction

Renewable plant biomass holds an eco-friendly and promising future in the years ahead, since it is an effective alternative source of renewable energy in the current scenario of depleting oil reserves, global warming, and growing environmental concerns. The biomass can be converted to other valuable forms of energy by a number of processes such as biological, mechanical and chemical. Pyrolysis has been applied for thousands of years for charcoal production and historical use of pyrolysis dates back to ancient Egyptian times, when they were using pyrolysis for the preparation of tar for caulking boats and as an embalming agent [2]. In recent years, it has regained popularity in an effort to decrease the carbon footprint and identify alternative sources of energy and value-added. In the early 1980s, the pyrolysis process was improved and researchers were able to obtain better yields using a fast pyrolysis, in which a biomass feedstock is heated at a rapid rate and the vapors produced are condensed rapidly [2,4]

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