Evaluation of phenolic bioactive-linked functionality of blackberry cultivars targeting dietary management of early stages type-2 diabetes using in vitro models

Common blackberry (Rubus spp.) is a rich source of phenolic antioxidants and has potential as a dietary source for the management of non-communicable chronic diseases (NCDs) such as early stages type 2 diabetes (T2D). While the potential health benefits are well-known, a gap in knowledge exists regarding differences in bioactive phenolic profiles of various commercial blackberry cultivars. Therefore, the main objective of this study was to screen and compare different blackberry cultivars for their phenolic antioxidant-linked functionalities targeting dietary management of early stages T2D using in vitro assay models. Water and 12% ethanol extracts of 13 blackberry cultivars were screened for total soluble phenolic (TSP) content, phenolic profile (HPLC), total antioxidant activity (DPPH scavenging), alpha-glucosidase, alpha-amylase, and angiotensin-l-converting enzyme (ACE) inhibitory activities. Overall, higher TSP content, moderate to high antioxidant activity, and high alpha-glucosidase inhibitory activity were found in ethanol extracts when compared to the water extracts. Among cultivars Natchez, A2215, Navaho, Ouachita, Chickasaw had higher TSP content, high alpha-glucosidase inhibitory activity (even at 1/5 th dilution), and higher catechin in water and rutin in ethanol extracts. High DPPH radical scavenging activity was observed in cultivars A2195, Prime Jan, Chickasaw, APF 27, and Navaho, while A2195, APF27, Ouachita, and Navaho had higher alpha-amylase inhibitory activity. Based on the results of this study, screened blackberry cultivars such as A2195, Ouachita, Navaho, and Natchez can be further evaluated as a whole fruit or functional ingredients for the dietary management of early stages T2D in animal models. (C) 2016 Elsevier B.V. All rights reserved.