Genetic and environmental variation in anthocyanins and their relationship to antioxidant activity in blackberry and hybridberry cultivars

Dietary anthocyanins (ACYs) may give health benefits through their antioxidant activity (AA) or other physiological effects. We examined AA and ACY profiles and contents in 16 blackberry and hybridberry (Rubus L. species) cultivars harvested in 2002 and 2003 in New Zealand and Oregon. Total ACY content varied widely among cultivars harvested from a single site in a single year (e.g., from 58 to 343 mg/100 g fruit Oregon in 2003). For the 12 cultivars common to both sites and years, cultivar and year within location significantly affected total ACY content, accounting for 40% and 10% of total variation, respectively. Cultivar interactions with both location and year within location were also significant, together accounting for 39% of variation. Cyanidin 3-O-glucoside and cyanidin 3-O-rutinoside were identified in all cultivars in both locations in at least 1 year. Compared with total ACY, cultivar accounted for more variation in these two ACYs (63% and 92%, respectively), while cultivar interactions together accounted for a smaller, but statistically significant, proportion of variation (23% and 7%, respectively). Cyanidin 3-O-sophoroside and cyanidin 3-0-(2(G)-glucosylrutinoside) were identified in only four cultivars. Cultivar effects accounted for 64% and 76% of variation in these ACYs, respectively, while cultivar interactions together contributed 18% and 24%, respectively. For AA, cultivar effects were not significant, contributing 11% of variation; in contrast, year effect and cultivar x environment interactions were significant, contributing 22% and 55% of total variation, respectively. Based on cultivar means for all 16 genotypes, the phenotypic correlation between AA and total ACY was positive but lower than that between AA and total phenolic content (TPH) (r = 0.63 and 0.97, respectively). Combinations of individual ACYs did not provide higher correlations with AA. Thus, ACY profiles and content are not as useful as TPH as a proxy measurement for AA.