Abstract:

Purpose: To optimize the procedure for isolating flavonoids from blueberry leaves by microemulsion liquid
chromatography (MELC) and to quantify the flavonoids obtained under the optimum conditions. Methods: Four MELC
conditions including surfactant, cosurfactant, pH of the mobile phase and organic phase were optimized. Results: The
optimum chromatographic conditions were determined as follows: 2.5% Brij-35 act as the surfactant, 8% 1-butanol as the
cosurfactant, the mobile phase adjusted to pH 3.2 with 0.5% acetic acid, and 0.8% ethyl acetate as the organic solvent.
The flavonoids in blueberry leaves could be separated efficiently and quantified precisely in 20 minutes under the above
conditions. Conclusions: The flavonoids in blueberry leaves included catechinic acid (9.76 mg/g), rutin (13.12 mg/g),
kaempferol (31.04 mg/g), quercetin (26.42 mg/g), and myricetin (20.30 mg/g).

Key words: blueberry leaves, flavonoids, microemulsion liquid chromatography, isolation, quantification