Peptococcus heliotrinreducans

Europine (165) Peptococcus heliotrinreducans (7a-Hydroxy-l-methylene-8a-pyrrolizidine) (173) (-) 166... 

Both the microorganisms mentioned above metabolized lasiocarpine (162), the gram-negative coccus leading to unidentified product(s) 165), and Peptococcus heliotrinreducans producing the 1-methylene derivative 175 166). 

Metabolism of the cyclic diesters retrorsine (166), monocrotaline (169), and crispatine (171) by a variety of mammalian liver microsome preparations and by Peptococcus heliotrinreducans has been reported. Mattocks and co-workers have studied the metabolism of retrorsine by liver microsome preparations from several sources 167-169) and have demonstrated the conversion of this alkaloid to the corresponding iV-oxide 167 and a pyrrolic metabolite formulated as 168. The formation of 168 via 167 and dehydration is mitigated against by the observation that retrorsine TV-oxide (167) does not give rise to a pyrrolic metabolite on incubation with rat liver microsomes 167), even though the enzyme system responsible for the production of 168 from retrorsine has many of the properties of the mixed-function oxygenases capable of N-oxidation 167,174). The metabolites of retrorsine... 

Similar products were obtained on incubation of monocrotaline (169) with a variety of liver microsomes of mammalian origin (170, 171). The V-oxide 170 was produced by liver microsomes from the rat and guinea pig, along with a pyrrolic derivative presumed to be 172 (170,171), whereas microsome preparations from other sources led to the production of only the pyrrolic derivative (171). Both monocrotaline and crispatine (171) were transformed to unidentified products by Peptococcus heliotrinreducans (166). 

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