Variations in ellagic acid, quercetin and myricetin in berry cultivars after preharvest methyl jasmonate treatments

Effect of preharvest methyl jasmonate treatments on the levels of ellagic acid, quercetin and myricetin in raspberries and blackcurrants was investigated. Varietal influence on treatment effect was particularly considered. For this purpose, different cultivars of raspberry (Glen Lyon, Glen Ample and Tumaleen) and blackcurrant (Ben Hope, Ben Alder and Gairn) were studied. The treatments were carried out by spraying two distinct concentrations of methyl jasmonate (0.01 and 0.1 mM) on berry plants. Cultivar to cultivar variations in the contents of ellagic acid and myricetin were observed in untreated berries. No varietal differences were however found in quercetin content. The effect of preharvest methyl jasmonate treatments was also cultivar independent. Preharvest methyl jasmonate always resulted in a general increase of the flavonoids studied, particularly, ellagic acid and quercetin. For instance, the content of ellagic acid increased approximately from 10 to 22 mg 100 g−1 and quercetin increased from 6 to 16 mg 100 g−1 in Glen Lyon raspberries. Similarly, ellagic acid increased from 6 to 11 mg 100 g−1 and quercetin from 4 to 9 mg 100 g−1 in Ben Hope blackcurrants. Preharvest methyl jasmonate treatment can be useful to food industry to obtain berries with enhanced health promoting properties.