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

Abstract

Anthoxanthuln species are unusual among British grasses in their content of coumarin, a compound whose presence in sweet clover (MeZiZotus 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 (9-coumaric) acid were found in annual sweet vernal ( A . puelzi) 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 (Anthoxanthuln 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 o€ 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-.--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 t o sheep and rabbits, do not suggest that the increased use of Anthoxanthum species in pastures would lead to detrimental effects. IntroductionThe occurrence of coumarin in most species of sweet clover appears to reduce the palatability of the crop ; under certain conditions it is said to be converted to the anticoagulant dicoumarol (3,3-methylene-bis-4-hydroxycoumarin), the toxic principle in sweet clover di~ease.l-~ This disease is characterised by a low clotting power of the blood with extensive and frequently fatal haemorrhages in such animals as cattle and sheep. Sweet vernal ( A . odoratum) is the only common British grass that contains considerable amounts of coumarin and, although of little agricultural importance a t present, it is a common constituent of permanent pasture ; it may be more widely used following the study and testing of improved selections of this grass by Borril at the Welsh Plant Breeding Station. The present work is an extension of earlier studies on the coumarin content of this grass in which the related compounds were estimated as a single fraction.4> In view of their possible rBle in dicoumarol formation, they have now been identified in fresh plant material and in spoilt hay. The annual form of sweet vernal...

The biosynthesis of dicoumarol

“…These haemorrhagic properties were shown by Stahmann, Huebner & Link (1941) to be due to the presence of dicoumarol (I). Similar spoilage has been shown to occur with hay from Anthoxanthum odoratum (Davies & Ashton, 1964).…”

“…nigrican8 could form dicoumarol and 4-hydroxycoumarin from o-coumaric acid, but not from coumarin. This has been confirmed by Davies & Ashton (1964) using hay from oat grass (Arrhenatherum elatius) and cocksfoot (Dactylis glomerata) inoculated with Pen. jenseni and o-coumaric acid.…”

Mechanism and Application of Baker–Venkataraman O→C Acyl Migration Reactions

“…90 Furthermore, examples of isolated naturally occurring coumarins (specifically, dicoumarol and umbelliferone) are well known for their anticoagulant properties. 91 Given their importance, Snieckus and co-workers documented a novel and general method for the synthesis of substituted 4-hy-…”

Natural toxic background in the food of man and his animals

“…These and other investigators mistakenly attributed dicoumarol formation to the presence of coumarin in the hay. Recently, it has been established both on hay (Davies and Ashton, 1964) and in pure culture (Beilis et al, 1967) that the green plants actually produce /ra«i-2-hydroxycinnamic acid, which subsequently is converted by any of several fungal species to 4-hydroxycoumarin and then to the stock-killing toxicant.…”