title: Physiological activity of warburganal and its reactivity with sulfhydryl groups.
abstract: Warburganal, a unique dialdehyde sesquiterpene isolated from East African Warburgia plants, showed a strong antifungal activity. However, this growth inhibition in Saccharomyces cerevisiae was reversed with L-cysteine. In addition, warburganal inhibited the alcoholic fermentation of S. cerevisiae while L-cysteine reversed this inhibition. When alcohol dehydrogenase, a sulfhydryl enzyme, was incubated with warburganal, the enzyme activity decreased with time. The decrease was more rapid at alkaline pH. L-Cysteine prevented this enzyme inhibition by warburganal but could not restore the enzyme activity lost already due to warburganal. Warburganal lost its characteristic ultraviolet absorption spectrum in the presence of L-cysteine. The change in absorbance was favored at alkaline pH, indicating Michael reaction type addition of L-cysteine to warburganal. Based on these observations, a variety of physiological activities due to warburganal appear to result from its irreversible reactivity with sulfhydryl groups.
mesh_terms: D000429:Alcohol Oxidoreductases / Q000037:antagonists & inhibitors; D000935:Antifungal Agents; D001419:Bacteria / Q000187:drug effects; D003545:Cysteine / Q000494:pharmacology; D005285:Fermentation; D005658:Fungi / Q000187:drug effects; D007700:Kinetics; D008826:Microbial Sensitivity Tests; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000378:metabolism; D012717:Sesquiterpenes / Q000494:pharmacology*; D013438:Sulfhydryl Compounds / Q000494:pharmacology*; D013439:Sulfhydryl Reagents / Q000494:pharmacology; D013997:Time Factors
chemical_list: D000935:Antifungal Agents; D012717:Sesquiterpenes; D013438:Sulfhydryl Compounds; D013439:Sulfhydryl Reagents; C037080:warburganal; D000429:Alcohol Oxidoreductases; D003545:Cysteine