
Coumarin (1,2-Benzopyrone) 
A bacterium isolated from soil metabolized coumarin to L-tyrosine 
in the culture medium (Levy and Weinstein, 1964a, b). In other studies, 
coumarin was converted to 7-hydroxycoumarin by Penicillium (Bellis, 1958). 
Additional studies have indicated that a-coumaric acid and melilotic acid 
were intermediates in the degradation of coumarin. A similar pathway in 
animals was suggested by experiments with rats (Booth et al., 1959) and 
rabbits (Booth et al., 1959; Furuya, 1958a, b; Mead et al., 1958). 
Urine from rabbits administered coumarin (I) was collected and 
examined for coumarin metabolites. 3-Hydroxycoumarin (II), 7-hydroxy- 
coumarin (III), both free and as glucuronate conjugates (IV) and 
sulfate (V), and a trace of 8-hydroxycoumarin (XXIII) were detected. 
A small amount of o-coumaric acid (XIV) was detected in the free form 
and as the glucuronide. o-Coumaric acid was partially reduced, forming 
melilotic acid (XX), and cyclized to form dihydrocoumarin (XXII). Traces 
of o-coumaroylglycine (XIX) formed from o-coumaric acid, (Furuya, 1958a; 
Mead et al., 1958). When o-coumaric acid was administered to rabbits, 
melilotoylglycine (XXI), o-coumaroylglycine (XIX), umbelliferone (III), 
and 4-hydroxycoumarin (7) were detected in the urine (Furuya, 1958b). 
In other studies, o-hydroxyphenylhydracrylic acid (XV), o-hydroxyphenyl- 
acetic acid (XVII), and o-hydroxyphenyllactic acid (XVI) were also detected. 
Similar findings were obtained with rats (Booth et al., 1959). In 
addition to the 3-, 7-, and 8-hydroxycoumarins, which are excreted in 
conjugation, the ferret, guinea pig and mouse also excrete 5-hydroxy- 
coumarin (XI) (Mead et al., 1958). 
58 
