Neutralization of the Antibacterial Effect of Natural Coumarin Ostruthine by Vitamins K

Abstract

THE effects of natural coumarin derivatives in the vegetable kingdom are well known, but their effect on micro-organisms has been little investigated up to now. We had earlier found that out of eighteen natural coumarins, for the greater part isolated from the family of Daucaceae, only ostruthine (6-geranyl-7-hydroxy-cou-marin) caused a marked inhibition of the growth of gram-positive micro-organisms. Related phenolic coumarins, such as umbelliferone (7-hydroxy-coumarin), were ineffective¹. The effect of ostruthine on the growth of the strain ‘BS 270’ of Staphylococcus aureus was not diminished by the addition of a surplus of glutathione, cysteine, thioglycolate, and 2,3-dimercaptopropanol², that is, substances which possess the ability to react with the lactone ring of the coumarin molecule³. Thus, the explanation of the effect of ostruthine can be found in the presence of a side-chain of ten carbon atoms, rather than in the lactone grouping of the molecule.