Phenolics were measured in leaves of apple cvs Jonagold and Golden Delicious, healthy and infected by Venturia inaequalis. Leaves were sampled from May to September 2005 and analyzed by HPLC. Phenolics detected were chlorogenic, caffeic, ferulic, p-coumaric, phloridzin, epicatechin, catechin, rutin and quercitrin. Total phenolics were determined with the Folin-Ciocalteu method. Infection by V. inequalis caused an accumulation of phenolics in infected leaves with up to 6.2- fold increase of flavonols, up to 6-fold increase of chlorogenic acid and up to 2.4-fold increase of the total phenolics.
In healthy and in apple scab infected leaves and apple fruits, we determined the content of individual and total phenolics. The leaves were collected several times throughout the growing season and the fruits at technological maturity. In the leaves and fruit were detected hydroxycinnamic acids, flavan-3-ols, dihydrochalcones and flavonols, total phenolics and antioxidant capacity. The infection with scab caused significantly higher levels of individual and total phenolics in apple leaves as well as in the fruits.