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ARTICLE

Matrix Assisted Laser Desorption Ionization Time of Flight (MALDI-TOF)-Mass Spectrometry and ¹³C-NMR-Identified New Compounds in Paraberlinia bifoliolata (Ekop-Beli) Bark Tannins

by Liliane Nga¹, Benoit Ndiwe^1,2, Achille Bernard Biwolé¹, Antonio Pizzi^3,*, Jean Jalin Eyinga Biwole¹, Joseph Zobo Mfomo¹

1 Laboratory of Forest Resources and Wood Valorization, Training Unit in Engineering Sciences, Post Graduate School of Fundamental and Applied Sciences, University of Douala, P.O. Box 1872, Douala, Cameroun
2 Laboratory of Mechanics, Training Unit in Engineering Sciences, Post Graduate School of Fundamental and Applied Sciences, University of Douala, P.O. Box 2701, Douala, Cameroun
3 Laboratory of Studies and Research on Wood Material (LERMAB), University of Lorraine, Nancy, France

* Corresponding Author: Antonio Pizzi. Email:

(This article belongs to the Special Issue: Special Issue in Celebration of JRM 10 Years)

Journal of Renewable Materials 2024, 12(3), 553-568. https://doi.org/10.32604/jrm.2023.046568

Received 07 October 2023; Accepted 21 December 2023; Issue published 11 April 2024

Abstract

Extracts of plant origin, particularly tannins, are attracting growing interest for the sustainable development of materials in the industrial sector. The discovery of new tannins is therefore necessary. The aim of this work was to contribute to the understanding of the properties of Paraberlinia bifoliolata tannin by Matrix Assisted Laser Desorption Ionization Time of Flight Mass Spectroscopy MALDI-TOF/MS and Carbon 13 Nuclear Magnetic Resonance (¹³C NMR). The chemical composition of tannin extracted from Paraberlinia bifoliolata bark was determined, as was the mechanical strength of the resin hardened with Acacia nilotica extracts. Yield by successive water extraction was 35%. MALDI-TOF/MS analysis revealed the presence of three new compounds in this tannin, previously unknown in this family of extracts. These are 3-hydroxyproline acid, N-methyl-4-hydroxypipecolic acid and N-methyl-5-dihydroxypipecolic acid. The identification of the above molecules means that this tannin can be used for industrial applications, as a resin in the manufacture of particleboard and in the formulation of green corrosion inhibitors. This information is reinforced by ¹³C NMR spectrometry, which indicates the presence of several polyflavonoid units, confirming the condensed nature of the tannin. Thermomechanical analysis of the resin formed by the purified tannin of Paraberlinia bifoliolata to which a vegetal biohardener has been added provided a Modulus of Elasticity (MOE) value of 4840 MPa at 150°C, confirming its possible use as a binder resin in the manufacture of wood panels as well as for the formulation of a corrosion inhibitor.

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