Abstract: Many polyphenolic, antioxidants such as oleuropein, flavonoids and hydroxytyrosol exist in olive leaves. The identification of hydroxytyrosol in different breeds of olive leaves was carried out by HPLC moritored at 230nm with ODS column(Φ4.6mm×200mm,5μm), MeOH-0.2% acetic acid buffer 6:94(volume ratio)as mobile phase at flow rate 1mL/min.The contents of hydroxytyrosol were distributed from 0.3% to 0.8% in 10 breeds. The ultrasonic extract of hydroxytyrosol was studied by single factor and orthogonal experiment.The optimum extraction conditions were as follows:ultrasonic power 120W, 90% MeOH-H₂O as extractant, material-liquid ratio 1:20(g:mL), extraction time 20min.Meanwhile, a single compound of 95% content was seperated by AB-8 macroporous resin, silica gel column chromatography and preparative HPLC. It was identificated to be hydroxytyrosol by MS and NMR.

Key words: olive leaves, hydroxytyrosol, orthogonal test, chemical structure