Metabolism of pyrrolizidine alkaloids in the ovine rumen. II. Some factors affecting rate of alkaloid breakdown by rumen fluid in vitro

When the pyrrolizidine alkaloids heliotrine and lasiocarpine were incubated in vitro with sheep's rumen contents, a common metabolic product was formed. This compound was also found as an end-product of metabolism in the rumen contents of sheep fed on a ration containing the plant Heliotropium europaeum. Previously described rumen metabolites of the Heliotropium alkaloids were 1-methylenepyrrolizidine derivatives, e.g. l-goreensine. The newly found product represents a further stage of reduction of l-goreensine in which the 1-methylene group has been replaced by a 1-methyl group. This compound has been identified as 7ß-hydroxyla- methyl-8ß-pyrrolizidine, a previously unknown pyrrolizidine derivative.