Über Chalkone II

Abstract

More than 80% of these plants that contain chalcones, flavanones, flavones, or flavonols are of importance in regard to diseases of the skin and infected wounds. Several substituted chalcones were prepd. and tested, as well as some flavanones, for their antibacterial activity against Staphylococcus aureus and Salmonella paratyphi. All the compounds were effective against both test objects, the most effective being 2,2'' -dihydroxy-3,5,5'' -tribromo chalcone. These, as well as the other more effective substances, are derivatives of 2-hydroxy-chalcone. An OH-group in the 2'' position lessens bacteriostatic activity notably while Br in the 5'' position confers an increase in effectiveness. Chlorinated chalcones are less effective than their analogous Br compounds. To establish the extent to which the growth inhibition exhibited by chalcone derivatives is related to similar properties of the aldehydes and ketones involved in chalcone synthesis, the various raw materials involved were collectively tested on Staphylococcus. The results showed that derivatives of benzalde-hyde were far more effective than analogous substituted derivatives of acetophenone. Thus, the most effective chalcones are derived from the most active aldehydes. Of the chalcones from acetonaphthone those produced by use of bromosalicylaldehyde proved the most active. The inhibition effectiveness of naturally occurring flavanones and of 2[image] -hydroxy-5[image] -bromo-5,6-benzo-flavanones were of the same magnitude as those of the isomeric chalcones. The structure of the unsaturated ketones is considered responsible for the bacteriostatic effects of chalcone. That these effects can be lessened through addition of serum is not to be ascribed to cysteine antagonism.