AMORIM, S. L.; http://lattes.cnpq.br/6569151092531078; AMORIM, Sara Lucena de.
Résumé:
Cyanogenic plants had hydrocyanic acid as active principle, which is bound to cyanogenic
glycosides, and liberated after the hydrolysis of these compounds. In Brazil the important toxic
cyanogenic plants are: Manihot spp. (Euporbiaceae), including Manihot, esculenta (cassava) and
many wild species of Manihot; Anadenanthera colubrina (sinonimus: Anadenanathera macrocarpa
and Piptadenia macrocarpa) and Piptadenia viridiflora, trees from the Leguminoseae Mimosideae
family; Sorghum spp. (gramineae); and Prunus sellowii and P. sphaerocarpa, trees from the
Rosaceae family. The intoxication by M. esculenta occurs, frequently, when ruminants consume the
roots shortly after collection. The intoxication by wild Manihot spp occurs when cattle or goats
consume the plant after sprouting. The intoxication by Anadenanathera spp. and Prunus spp.
occurs, when ruminants consume leaves from fallen trees or branches, and the intoxication by
Sorghum spp. occurs after the ingestion of the sprouting young plants. Few outbreaks of
intoxication by Cynodon dactylon (Tifton) had been reported. Because the fast absorption of
cyanide, clinical signs of cyanide intoxication are observed immediately after or during plant
ingestion. They are characterized by increased respiratory and cardiac frequencies, cyanotic mucous
membranes, salivation, intense muscular tremors, nystagmus, incoordination, and falling, followed
by lateral recumbence, opisthotonos, accentuated dispnea, paddling movements, and finally coma.
Death occurs due to respiratory failure between 15 minutes and few hours after first clinical signs.
If ingested in low doses, cyanide also can cause chronic intoxication, with lesions on the nervous
system, thyroid and other organs. Cyanide is detoxicated by enzyme rodanase which change it to
tiocyanate, which is a not toxic substance. Cyanide can be detoxicated by grunding or trituration,
hay production, heating to remove the residues of free cyanide; by pressing, where the soluble
cyanogenic glycosides are dragged with the water; by cooking; by fermentation; and by or
dehydratation. Affected animals are treated by the intravenous administration of 50 ml for 100 kg
body weight of a sodium tiosulfate 20% solution. The prevention of the intoxication is by avoiding
the ingestion of large amounts of the toxic plants in a short period.