3.3. Identification of Phenolic Compounds by HPLC
Polyphenol qualitative determination of the blueberry leaves was performed by HPLC analysis. As it is shown in Table 2, nine phenolic components were identified including gallic acid, protocatechui acid, caffeic acid, vanillic acid, syringic acid, p-coumaric acid, ferulic acid, quercetin and kaempferol. The results also demonstrated that the blueberry leaves were rich in phenolic compounds such as flavonoids and phenolic acids, which are widely known as antioxidants and antimicrobial agents [1,5]. Those phenolic compounds varied with different extract solvents. The major compounds were caffeic (68.06%), syringic (11.76%) and ferulic acid (9.49%) in 50% ethanol extracts, as well as protocatechuic (39.48%), caffeic (32.23%) and vaillic (15.70%) in 95% ethanol extracts.