Phenolic compounds in black currant leaves – an interaction between the plant and foliar diseases?

Interactions between phenolic compounds in black currant leaves and foliar diseases may be important in breeding for resistant genotypes with a nutritional high profile for human applications. For increased understanding of such interactions, we evaluated the presence of major fungal diseases by visual inspection, and content of phenolic compounds by HPLC in leaves of five segregating black currant breeding populations. Eight individual flavonols (e.g. quercetin-3-O-glucoside, quercetin-3-O-rutinoside and kaempferol-malonylgucoside), three flavan-3-ols (epigallocatechin, catechin and epicatechin) and two chlorogenic acids (neochlorogenic acid and chlorogenic acid) were significantly correlated to the leaf diseases. Rib-0701 was the population possessing the highest content for several of the compounds, while genotype differences existed for content of various phenolic compounds and resistance to the diseases. The high variability of content of phenolic compounds opens up for opportunities to breed resistant genotypes with improved health properties of the leaves for functional food products.