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Publication Details
AFRICAN RESEARCH NEXUS
SHINING A SPOTLIGHT ON AFRICAN RESEARCH
agricultural and biological sciences
Insecticidal and fungicidal activity of new synthesized chitosan derivatives
Pest Management Science, Volume 61, No. 10, Year 2005
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Description
Chitosan, the N-deacetylated derivative of chitin, is a potential biopolysaccharide owing to its specific structure and properties. In this paper, we report on the synthesis of 24 new chitosan derivatives, N-alkyl chitosans (NAC) and N-benzyl chitosans (NBC), that are soluble in dilute aqueous acetic acid. The different derivatives were synthesized by reductive amination and analyzed by 1H NMR spectroscopy. A high degree of substitution (DS) was obtained with N-(butyl)chitosan (DS 0.36) at a 1:1 mole ratio for NAC derivatives and N-(2,4-dichlorobenzyl)chitosan (DS 0.52) for NBC derivatives. Their insecticidal and fungicidal activities were tested against larvae of the cotton leafworm Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae), the grey mould Botrytis cinerea Pers (Leotiales: Sclerotiniaceae) and the rice leaf blast Pyricularia grisea Cavara (Teleomorph: Magnaporthe grisea (Hebert) Barr). The oral feeding bioassay indicated that all the derivatives had significant insecticidal activity at 5 g kg-1 in artificial diet. The most active was N-(2-chloro-6-fluorobenzyl)chitosan, which caused 100% mortality at 0.625 g kg-1, with an estimated LC50 of 0.32 g kg-1. Treated larvae ceased feeding after 2-3 days; the mechanism of action remains unknown. In a radial hyphal growth bioassay with both plant pathogens, all derivatives showed a higher fungicidal action than chitosan. N-Dodecylchitosan, N-(p-isopropylbenzyl) chitosan and N-(2,6-dichlorobenzyl)chitosan were the most active against B cinerea, with EC50 values of 0.57, 0.57 and 0.52 g litre-1, respectively. Against P grisea, N-(m-nitrobenzyl)chitosan was the most active, with 77% inhibition at 5 g litre-1. The effect of different substitutions is discussed in relation to insecticidal and fungicidal activity. © 2005 Society of Chemical Industry.
Authors & Co-Authors
Rabea, Entsar I.
Belgium, Ghent
Universiteit Gent
Badawy, Mohamed E.I.
Belgium, Ghent
Universiteit Gent
Rogge, Tina M.
Belgium, Ghent
Universiteit Gent
Stevens, Christian V.
Belgium, Ghent
Universiteit Gent
Höfte, Monica M.
Belgium, Ghent
Universiteit Gent
Steurbaut, Walter
Belgium, Ghent
Universiteit Gent
Smagghe, Guy J.
Belgium, Ghent
Universiteit Gent
Statistics
Citations: 123
Authors: 7
Affiliations: 1
Identifiers
Doi:
10.1002/ps.1085
ISSN:
1526498X
Research Areas
Health System And Policy