The Pharmacokinetics of Prunasin, a Metabolite of Amygdalin

Abstract

The pharmacokinetics of prunasin have been investigated in the dog. The results are compared with results obtained with amygdalin. The volume of distribution and the clearance of prunasin are larger than those of amygdalin. The oral bioavailability of prunasin is approximately 50%, whereas amygdalin is hardly absorbed unchanged.

Opinion of the Scientific Panel on contaminants in the food chain [CONTAM] related to cyanogenic compounds as undesirable substances in animal feed

“…Thus, although cyanogenic glycosides may undergo acid hydrolysis (Eyjolfsson, 1970;Bradbury et al, 1991), the conditions in the mammalian stomach, together with the relatively short passage time, will allow the main fraction to pass to the intestine. Once in the intestine of a non-ruminant, the glycosides are absorbed, as has been demonstrated for linamarin in a number of animal species and in humans (Barrett et al, 1977;Philbrick et al, 1977, Brimer andRosling, 1993;Hernandez et al, 1995), and for prunasin (prulaurasin) and amygdalin in different animal species (Carter et al, 1980;Rauws et al, 1982Rauws et al, , 1983Sakata et al, 1987). Alternatively they will be hydrolysed by micro-organisms (Carter et al, 1980;Bourdoux et al, 1982;Poulton, 1993).…”

“…As already described in Chapter 6, all cyanogenic glycosides investigated so far can be absorbed into the blood stream (Barrett et al, 1977;Philbrick et al, 1977, Brimer andRosling, 1993;Hernandez et al, 1995;Carter et al, 1980;Rauws et al, 1982Rauws et al, , 1983Sakata et al, 1987). However, all evidence available indicates that the absorbed glycosides (no matter the structure of the aglycone or the sugar part) are excreted unchanged in the urine of the organism (Ames et al, 1978;Moertel et al, 1981, Brimer andRosling, 1993;Hernandez et al, 1995).…”

“…Alternatively they will be hydrolysed by micro-organisms (Carter et al, 1980;Bourdoux et al, 1982;Poulton, 1993). According to Rauws et al (1983) the oral bio-availability of prunasin is considerably higher than that of amygdalin (measured in dogs). This probably is attributable to the fact that (at least in rat) in jejunum and ileum, amygdalin is not absorbed as such, but is partly hydrolysed to prunasin which in turn can be transferred intact across the intestinal wall, without cleavage of the glycosidic bond (Strugala et al, 1995).…”

“…Remaining amygdalin, prunasin (the cyanogenic glucosides formed by removal of the terminal glucose moiety from the amygdalin) as well as the corresponding cyanohydrins and the formed cyanide are in general absorbed into the blood stream (Rauws et al, 1983;Barrett et al, 1977;Strugala and Elbers, 1984). Dietary protein deficiency prolongs the time of metabolism and hence increases the toxicity of cyanogenic glycosides in the body as demonstrated for linamarin (Umoh et al, 1986).…”

“…The volume of distribution and clearance for amygdalin were found to be 0.19 L/kg and 0.39 L/kg respectively, while the corresponding figures for prunasin were 0.34 L/kg and 0.55 L/kg. For both compounds a two-compartment model was found to fit the kinetics measured after intravenous administration (Rauws et al, 1982(Rauws et al, , 1983.…”