Benzoic and salicylic acids isolated from a glycoside of aspen bark and their effect on Hypoxylon pruinatum

Benzoic and salicylic acids, isolated from an unknown glycoside of aspen bark, were identified as the main fungistatic factors of this compound against Hypoxylon pruinatum (Klotzsche) Cke. The identity of the carboxylic acids was established by thin-layer chromatography and ultraviolet and infrared spectrophotometry.On a malt agar medium, benzoic acid inhibited the growth of the fungus at 1 × 10−3 M, whereas salicylic acid at the same concentration stimulated growth. Complete inhibition of growth of the fungus was obtained with benzoic acid at a concentration of 4 × 10−3 M and with salicylic acid at 5 × 10−3 M. Total inhibition was also obtained when both benzoic and salicylic acids, each at a concentration of 2 × 10−3 M, were simultaneously present in the malt agar medium.On a synthetic medium, benzoic acid and glucose, each at a concentration of 1 × 10−3 M, inhibited the growth of the fungus. At this concentration salicylic acid had no effect.When ammonium nitrate was replaced simultaneously by asparagine, alanine, and glutamine, benzoic acid at 2 × 10−3 M, and glucose at 3 × 10−3 M promoted the growth of the fungus. The same growth was also obtained when benzoic acid at 1 × 10−3 M and glucose at 1 × 10−3 M were both added to the medium.