554 



5. QUINONES 



parison of menadione with 1,4-naphthoquinone (see accompanying tab- 

 ulation). Menadione is more active in some organisms and less active in 

 others, and for S. aureus both situations have been reported. Such results, 



Organism 



Potency ratio 

 {MD/1,4-NQ) 



Reference 



taken in conjunction with the several possible mechanisms by which these 

 quinones can inhibit growth, are not susceptible to accurate analysis. 

 A very similar picture is presented in comparing toluquinone with p-ben- 

 zoquinone, potency ratios (TQ/p-Q) from 0.5 to 3.2 being observed; fur- 

 thermore, for E. coli a ratio of 0.57 was reported by Cooper and Mason 



