Blueberry leaves from 73 different cultivars in southeastern China as nutraceutical supplements rich in antioxidants.

Blueberries (Vaccinium spp.) have great beneficial effects, and their leaves are rich in phenolics. In the present study, the total phenolic, total flavonoid, and proanthocyanidin contents in the leaf extracts from 73 different blueberry cultivars among five categories were investigated. The phenolic composition was analyzed, and the antioxidants were also evaluated. Here, a total of 23 individual phenolic constituents were identified, among which eight predominant phenolics were quantified, including five caffeoylquinic acids, two quercetin glycosides, and one kaempferol glycoside. The different cultivars could be well clustered according to their phenolic compositions and antioxidant capacities. The correlations among the quantified phenolic constituents and the antioxidant capacities were determined using principal component analysis. The results indicated that blueberry leaves may be a potential resource of antioxidant phenolics, and the differences among the cultivars should be considered when blueberry leaves are further developed.