Abstract:

Oleanolic acid (OA) and ursolic acid (UA) were identified by mass spectrometry (MS) in almond green husk
extract. Further, a high performance liquid chromatographic (HPLC) method was established for the determination of the
contents of OA and UA, and the extraction conditions were optimized using single factor and orthogonal array experiments.
The HPLC conditions were set as follows: separation column, Platisil ODS C18 (250 mm × 4.6 mm, 5 μm); mobile phase,
methanol-0.2% phosphorus acid (85:15, V/V); flow rate, 0.8 mL/min; column temperature, 20 ℃; and detection wavelength,
210 nm. In the range of 0.005–0.5 mg/mL (R2 = 0.999 9), both OA and UA presented a good linear relationship. The average
recoveries of OA varied from 89.67% to 94.85% with RSD of 1.28%–3.16% (n = 3). The average recoveries of UA ranged
from 88.67% to 94.77%, and the RSD was between 1.07% and 1.92% (n = 3). The optimum conditions for extracting
OA and UA from almond green husk extract were as follows: 95% ethanol as extractant; solid/solvent ratio, 1:40 (g/mL);
extraction time, 40 min; and 3 extraction cycles.

Key words: almond green husk, oleanolic acid (OA), ursolic acid (UA), high performance liquid chromatography (HPLC)