608 NATURAL PRODUCTS

of different pyrrolizidine alkaloids (Cited in F.C.T. 1968, 6, 549), it has not yet been estab- lished whether these individual differences stem from direct cytotoxic action or from the facility with which the alkaloids are converted in vivo to metabolites more or less toxic than the parent compound. To throw some light on the situation, the above authors studied in sheep the excretion of the alkaloid heliotrine and its metabolites containing an intact pyrrolizidine ring, following infusion intravenously or perfistulum into the duodenum.

The same three metabolites with intact pyrrolizidine rings (heliotridine trachelanthate, heliotrine N-oxide and heliotridine) were detected by thin-layer chromatography in the urine, blood and bile. The total amount of alkaloid in the urine was much greater than that in the bile but the relative amounts of heliotrine and the three metabolites excreted were similar in both fluids. The proportion of the dose recovered was highest (24 %) following rapid intravenous injection, less with slow intravenous infusion and lowest (6 %) after slow infusion into the duodenum. Due to the absence of data on faecal output it is not certain whether this is attributable to incomplete absorption or to greater metabolism. A compari- son of the results obtained suggests that the lower the concentration of heliotrine in the blood, the greater the proportion that is metabolized. There was no significant variation in the time required for heliotrine to appear in the urine following the different modes of administration, but the maximum rate of urinary excretion attained varied directly with the concentration of heliotrine reached in the blood.

The three metabolites identified are less toxic than heliotrine, so it is considered that their appearance indicates metabolic processes by which this alkaloid may be detoxified in vivo.

2037. A round-up of fungal toxins

Krogh, P. (1969). The pathology of mycotoxicoses. J. stored Prod. Res. 5, 259. This review makes brief reference to the pathological changes induced in animals and

man by the more commonly known fungal toxins. Toxins primarily affecting the liver and/or kidneys include sporidesmin, aflatoxin, ochratoxin, luteoskyrin and a chlorine- containing peptide from Penicillium islandicum, rubratoxins, citrinin and P. viridicatum toxin. The last-named toxin appears to affect up to 7 % of Danish pigs and its primary toxic effect is degeneration of the renal tubules. Fungal toxins launching their attack on other sites include zearalenone (reproductive system), citrioviridin (central nervous and circulatory systems), Stachybotryo-toxins (blood and digestive systems), dendrodocins (blood and heart), Fusarium sporotrichiella toxins (haematopoietic and digestive systems), F. graminearum toxin (central nervous system), scirpenes (digestive system), ergot (repro- ductive and circulatory systems) and toxins from the sclerotia of Claviceps paspali.

2038. Atiatoxin not so guilty?

Hueper, W. C. (1969). Krebse bei Ratten und M~iusen nach Fiitterung mit kommerziellem Fischfutter. Z. Krebsforsch. 73, 141.

Aflatoxin has been widely condemned as the feed contaminant responsible for epidemics of primary liver cancer in rainbow trout, but some doubt has now been thrown on the extent of this responsibility.

Two different feeds which caused a high incidence of liver cancer in the trout were found to produce only benign liver tumours (adenomas and cholangiomas) in some of the rats and mice to which they were fed for up to 2 yr, although feeding with aflatoxin generally causes a high incidence of tumours and degeneration in the livers of rats. Moreover in both species there was a significant incidence of adenocarcinoma of the stomach and colon, two