Microdiffusion method with solid state detection of cyanogenic glycosides from cassava in human urine

• Published in: Food and chemical toxicology Vol. 31; no. 8; pp. 599 - 603
• Main Authors: Brimer, L., Rosling, H.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.08.1993; New York, NY Elsevier Science
• Subjects: Administration, Oral; Biological and medical sciences; Chromatography, Thin Layer; False Positive Reactions; Food toxicology; Glycosides - urine; Humans; Manihot; Manihot - metabolism; Medical sciences; Nitriles - urine; Thiocyanates - urine; Toxicology; Assay; Urine; Biological fluid; Manihot esculenta; Dicotyledones; Angiospermae; Plant origin; Euphorbiaceae; Spermatophyta; Cyanogenic glucoside; Food; Microassay
• ISSN: 0278-6915; 1873-6351
• DOI: 10.1016/0278-6915(93)90210-P

A method for quantitative determination of cyanogenic glycosides in human urine is described. It is based on enzymatic cleavage of the glycosides, microdiffusion of the hydrogen cyanide formed, solid state detection by colour formation on a picrate-impregnated sheet, and subsequent rating of the coloured spot by the absorption of transmitted light at 540 nm with a thin-layer (TLC) densitometer. The method has been tested using normal as well as pathological urines containing glucose, protein, leucocytes, blood and bacteria. The method allows quantification of urinary linamarin above 70 μmol/litre, in 40 μl urine. In Mozambican subjects consuming insufficiently processed cassava the mean urinary linamarin levels were 211 μmol/litre, indicating for the first time that substantial amounts of the main cyanogenic glycoside in cassava may be absorbed from the human gut and excreted intact in the urine.