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Biochemical basis of the toxicity of manipueira (liquid extract of cassava roots) to nematodes and insects
Author(s) -
Magalhães Claúdio P.,
XavierFilho J.,
Campos Francisco A. P.
Publication year - 2000
Publication title -
phytochemical analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 72
eISSN - 1099-1565
pISSN - 0958-0344
DOI - 10.1002/(sici)1099-1565(200001/02)11:1<57::aid-pca489>3.0.co;2-e
Subject(s) - chemistry , acetone , fermentation , glycoside , cyanohydrin , hydrolysis , biochemistry , food science , organic chemistry , catalysis
The presence of defence‐related proteins and the concentration of cyanogens in the cell‐sap solution of cassava roots (termed manipueira) have been investigated. It is demonstrated that manipueira is devoid of lectins, serine proteinase inhibitors and chitinase activity, although very low levels of α‐amylase inhibitory activity were detected. Within 6 h of storage, all of the major cyanogenic glycoside of cassava, linamarin, had disappeared, while the concentration of acetone cyanohydrin, the breakdown product of the hydrolysis of linamarin, had dropped to 40% of the initial value at zero time and remained unchanged until 72 h of storage. This stabilization of the acetone cyanohydrin during storage seems to be caused both by a drop in pH due to lactic fermentation, which prevents its spontaneous breakdown, and by the absence of α‐hydroxynitrile lyase in cassava roots. It is concluded that the well‐known toxicity of manipueira may be causally related to the stabilization of the acetone cyanohydrin. Copyright © 2000 John Wiley & Sons, Ltd.