engleski

Grafting black chokeberry (Aronia melanocarpa L., var. Viking) onto European rowan (Sorbus aucuparia L.) yields fruit with superior phytochemical content and bioactivity

Dark colored berry fruits are dietary sources of polyphenols, especially flavonoids and anthocyanins, with confirmed health benefits. Due to controversy surrounding genetically engineered plants, there is an incentive among the farmers to produce food crops with an increased content of bioactive compounds via seed selection, breeding, or grafting, without manipulations at the genetic level. Cuttings of black chokeberries (Aronia melanocarpa L., var. Viking) were grafted onto rootstocks of European rowan trees (Sorbus aucuparia L.) which grow wild in the forests of Gorski kotar (mountainous-highland Croatia). The trees set fruit after 2 years. For comparison, several own-rooted black chokeberry bushes were grown alongside the grafted European rowan trees, under the same environmental conditions Berriers from experimental plantings, as well as berries from wild-grown European rowan trees, were harvested at full maturation in late August, and subjected to the following analyses: size and weight measurements, the total phenol (Folin-Ciocalteu method), flavonoid (colorimetric assay with AlCl3) and anthocyanin (pH differential method) contents, as well as radical scavenging activity measured by the 1, 1-diphenyl-2-picrylhydrazyl (DPPH) method. The berries showed differences in average size and weight. Black chokeberries grafted onto European rowan tree exhibited the highest content of total phenols (14.25 ± 0.33 mg GAE/g FW), flavonoids (7.87 ± 0.25 mg CE/g FW) and anthocyanins (5.73 ± 0.03 Cyd-3-glu/g FW) in comparison with the berries from own-rooted black chokeberry bush (10.76 ± 0.51 mg GAE/g FW, 5.61 ± 0.28 mg CE/g FW, and 3.04 ± 0.03 Cyd-3-glu/ g FW, respectively) and berries from the wild European rowan tree (11.12 ± 0.15 mg GAE/g, 7.37 ± 0.25 mg CE/g FW, 0.38 ± 0.00 Cyd-3-glu/100 g FW). The free radical scavenging activity, defined as the extract concentration necessary to decrease the initial DPPH concentration by 50%, was expressed as EC50. Black chokeberries grafted onto European rowan tree showed the lowest EC50 values (10.2) and in turn the highest antioxidant capacity. A detailed analysis of phytochemical composition will supplement these preliminary findings.

bioactivity; chokeberry; European rowan; phytochemica

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