a-glucosidase inhibitory activity and antioxidant capacities in peel and pulp of mixed species blueberry (Vaccinium spp.) genotypes

Authors: Ehlenfeldt, Mark; WANG, SHIOW - Retired ARS Employee; Camp, Mary

Submitted to: Plant Genetic Resources: Characterization and Utilization
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/3/2014
Publication Date: 6/11/2014
Citation: Ehlenfeldt, M.K., Wang, S.Y., Camp, M.J. 2014. a-glucosidase inhibitory activity and antioxidant capacities in peel and pulp of mixed species blueberry (Vaccinium spp.) genotypes. Plant Genetic Resources: Characterization and Utilization. 13:190-194.

Interpretive Summary: Inhibition of the enzyme a-glucosidase is considered one of the effective measures for controlling diabetes by reducing glucose uptake. Blueberries have been found to be good sources of a-glucosidase inhibiting compounds. This study evaluated assorted blueberry hybrids for fruit antioxidant content and the influence of fruit peel and pulp on a-glucosidase inhibition. Higher levels of a-glucosidase inhibition and antioxidants were observed in peel tissue compared to pulp. Differences between hybrids were also evident. This information is useful to consumers interested in the health benefits of blueberries, to researchers trying to breed for improved fruit nutritive value, and to researchers interested in better understanding antioxidant components of blueberry fruit.

Technical Abstract: Variation in inhibition of a-glucosidase inhibitory activity, phenolic levels, anthocyanin levels, and antioxidant activity of peel and pulp was investigated in 19 blueberry genotypes [16 rabbiteye hybrid derivatives (Vaccinium ashei × Vaccinium spp.), 1 rabbiteye cultivar (V. ashei Reade) and 2 highbush hybrids (V. corymbosum L.). Peel tissue possessed significantly higher levels of a-glucosidase inhibitory activity, total anthocyanins (TA), total phenolics (TP), and antioxidant activities compared to pulp tissue, even though peel only makes up a small portion of the fruit. Significant positive correlations were found among a-glucosidase inhibitory activity, TA, TP, and the scavenging activities for: ROO·, ·OH, 1O2, and H2O2 in peel and pulp extracts. In peel tissue, the rabbiteye hybrid derivative, US 1247, possessed the highest levels of a-glucosidase-inhibitory activity and the highest levels of TA, TP, and highest antioxidants. In pulp tissue, the rabbiteye hybrid derivative, US 1382, had the highest relative levels of the same components.