Molecules (Jan 2023)

Deep Chemical and Physico-Chemical Characterization of Antifungal Industrial Chitosans—Biocontrol Applications

  • Gaël Huet,
  • Yunhui Wang,
  • Christian Gardrat,
  • Daphnée Brulé,
  • Amélie Vax,
  • Cédric Le Coz,
  • Frédérique Pichavant,
  • Silvère Bonnet,
  • Benoit Poinssot,
  • Véronique Coma

DOI
https://doi.org/10.3390/molecules28030966
Journal volume & issue
Vol. 28, no. 3
p. 966

Abstract

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Five different chitosan samples (CHI-1 to CHI-5) from crustacean shells with high deacetylation degrees (>93%) have been deeply characterized from a chemical and physicochemical point of view in order to better understand the impact of some parameters on the bioactivity against two pathogens frequently encountered in vineyards, Plasmopara viticola and Botrytis cinerea. All the samples were analyzed by SEC-MALS, 1H-NMR, elemental analysis, XPS, FTIR, mass spectrometry, pyrolysis, and TGA and their antioxidant activities were measured (DPPH method). Molecular weights were in the order: CHI-4 and CHI-5 (MW >50 kDa) > CHI-3 > CHI-2 and CHI-1 (MW 2 form, and CHI-3 contains a high amount of a chitosan calcium complex. CHI-2 and CHI-3 showed higher scavenging activity than others. The bioactivity against B. cinerea was molecular weight dependent with an IC50 for CHI-1 = CHI-2 (13 mg/L) ≤ CHI-3 (17 mg/L) P. viticola zoospores was important, even at a very low concentration for all chitosans (no moving spores between 1 and 0.01 g/L). These results show that even at low concentrations and under hydrochloride form, chitosan could be a good alternative to pesticides.

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