Supercritical fluid extraction of monoamine oxidase inhibitor from antler velvet

Supercritical fluid extraction (SFE) of the monoamine oxidase (MAO) inhibitor from antler velvet with CO2 was explored. The effect of different parameters, such as particle size, the kind of co-solvent, extraction temperature and pressure, on the extraction yield (Y) and the total inhibitory activity (TI) on MAO-B were investigated using three-level orthogonal array design. The experimental results show that when the absolute ethanol as co-solvent was used and the particle size was 120 μm, the extraction temperature was 70 °C, the extraction pressure was 30 MPa, the extract yield reached 3.58% and the TI of the extract was 3319.13 U/g. Evaluation of the inhibitory activity of extract on MAO indicated that the extracts had strong inhibitory effects on MAO-B, but had slight effects on MAO-A. The MAO-B activity was inhibited by 93.77% at the concentration of 278.15 mg/L, which was much higher than that of water extract and ethanol extracts. The compositions of estradiol, uracil, hypoxanthine, p-hydroxybenzaldehyde and phospholipids in the SFE extracts were identified, which were reported to have the inhibitory effect on MAO.