ANTIBACTERIAL ACTIVITY 543 



ANTIBACTERIAL ACTIVITY 



The potent antibacterial and antifungal activities of certain quinones 

 have led to their trial for use as antiseptics and in the treatment of systemic 

 infections. It is possible that some plants or their extracts used by primi- 

 tive peoples or in folk medicine owe their activity to naturally occurring 

 quinones. The leaves and berries of many of the Ericaceae have been widely 

 used for centuries in the treatment of urinary tract infections. Arctostaphylos 

 uva-ursi (bearberry) is the best known of these and contains appreciable 

 amounts of arbutin (p-benzohydroquinone-/?-D-glycopyranoside) in the 

 leaves, the ingestion of which leads to the appearance of p-benzoquinone in 

 the urine (Madaus and Koch, 1939). The golden rhododendron has been 

 used medicinally in Siberia and contains 4% arbutin and 0.76% p-benzo- 

 hydroquinone in the leaves, so that extracts inhibit the growth of several 

 pathogens (Medvedeva, 1952). In the search for effective antibiotics oc- 

 curring in fungi and plants it was soon recognized that many of the active 

 substances are quinones (Florey et at., 1949; Huisman, 1950), and it was pos- 

 tulated that the antibacterial action might be related to the reaction with 

 SH groups (Geiger, 1946; Rinderknecht et al., 1947). Some simple antibiotic 



O HO O 



^OCHj HjCO" ^ >f XH2COCH3 



b 



XI 



Fumigatin Spinulosin 



quinones are fumigatin from Aspergillus fumigatus, spinulosin from Pe- 

 nicillium spinulosum, and javanicin from Fusarium javanicum. Other 

 antibiotics, such as geodin and penicillic acid, contain the grouping 



\ I I 



c = c — c = o 



but are not true quinones. The antibacterial activity of these and other 

 quinones has stimulated much screening work to find compounds useful 

 in agriculture and medicine, but there has been very little investigation of 

 the metabolic effects or the mechanisms of inhibition. Some of the results 

 of this work are summarized in Table 5-9, from which it is clear that various 

 quinones completely prevent the growth of gram-positive bacteria at con- 

 centrations in the range 0.01-0.05 raM. 



The results in Table 5-9 are not to be considered as quantitatively 



