Abstract:

The ultrasonic-assisted extraction of polyphenols from mature leaves of Zaosu pear was optimized by
investigating the effects of ultrasonic time, solid-to-solvent ratio and solvent type on extraction efficiency. The components
and contents of pear leaf polyphenols were determined by ultra performance liquid chromatography (UPLC) coupled with
photodiode array detector (PDA). The results showed that the optimal conditions for arbutin extraction from pear leaves were
found to be 30 min extraction carried out twice using 70% aqueous ethanol as the extraction solvent with a solid-to-solvent
ratio of 1:150 (g/mL) at an ultrasonic power of 500 W, while the optimal conditions for the extraction of both caffeoylquinic
acid and flavonols were identical to those for arbutin except for an extraction time of 25 min and a solid-to-solvent ratio
of 1:125 (g/mL). Ten polyphenols were detected in pear leaves under the optimized conditions with total contents ranging
from 17.852 to 61.149 mg/g, and the contents of arbutin were 7.934–36.854 mg/g. Therefore, pear leaves can be used as an
excellent natural material for developing cosmetics, health products and medicines.

Key words: Zaosu pear leaf, ultra performance liquid chromatography (UPLC), polyphenols, extraction, components