Portal de Periódicos da CAPES

Coumarin and related compounds of Anthoxanthum puelii and Melilotus alba and dicoumarol formation in spoilt sweet vernal and sweet clover hay

1964; Wiley; Volume: 15; Issue: 11 Linguagem: Inglês

10.1002/jsfa.2740151101

1097-0010

E. G. Davies, W. M. Ashton,

Phytochemicals and Antioxidant Activities

Abstract Anthoxanthum species are unusual among British grasses in their content of coumarin, a compound whose presence in sweet clover ( Melilotus alba ) has been alleged to give rise to the production of the anticoagulant dicoumarol in “sweet clover disease”. By chromatographic and spectrophotometric techniques, 7‐hydroxycoumarin 6‐glucoside (aesculin) and o ‐hydroxyhydrocinnamic (melilotic) acid, trans ‐2‐hydroxycinnamic ( o ‐coumaric) acid, and 4‐hydroxycinnamic ( p ‐coumaric) acid were found in annual sweet vernal ( A. puelii ) and sweet clover. 3‐Methoxy‐4‐hydroxycinnamic (ferulic) acid was also found in annual sweet vernal, and 7‐hydroxycoumarin in sweet clover. Dicoumarol formation was studied in spoilt (i.e., mouldy) hay made from perennial sweet vernal ( Anthoxanthum odoratum ). The hay contained very small amounts of dicoumarol, and larger amounts were present when the hay was inoculated with Penicillium jenseni and when formaldehyde was added. During spoilage the coumarin content of the hay decreased while the related compounds increased in amount and reached a steady value in about 4 weeks. Although the coumarins and related compounds of annual sweet vernal and sweet clover are virtually the same, much higher levels of dicoumarol were found in the latter after spoilage, possibly because, under the conditions of the experiment, it became more mouldy than the former. Experiments with a mixed oatgrass/cocksfoot hay indicated that added trans ‐2‐hydroxycinnamic acid and not coumarin gave rise to 4‐hydroxycoumarin which reacted with formaldehyde to produce dicoumarol. This suggests that this acid and not coumarin is the precursor of dicoumarol. The very small amounts of dicoumarol found in spoilt perennial sweet vernal hay, and the results of earlier experiments in which such hay was fed to sheep and rabbits, do not suggest that the increased use of Anthoxanthum species in pastures would lead to detrimental effects.