Seasonal variations of naphthoquinone contents (juglone and hydrojuglone glycosides) in Juglans regia L.

The aim of the present study was to determine content naphthoquinones (juglone and hydrojuglone glycosides) in different tissues walnut plants (Juglans regia L.) through growing season, for French cultivar 'Franquette' Slovenian 'Rubina'. Husk, leaves, bark, catkin pistillates were studied. Naphthoquinones contents catkins (male flowers) (female J. regia, have best our knowledge not been defined any metabolic studies date. identified quantified by HPLC/MS. all individual total phenolics consistent with those which suggests that phenolic compounds are redistributed from bark after flowering prevent loss these valuable plant compounds. lowest husks both cultivars, while highest observed leaves. glucoside pistillate followed rhamnoside pentoside juglone husk catkin. Quantification during growth periods provides data on when extraction might be useful further isolation or pharmaceutical studies.