Purification of menthone and menthol from Mentha haplocalyx by suspension particle assisted solvent sublation, neuroprotective effect in vitro and molecular docking of menthol on amyloid-β

Suspension particle assisted solvent sublation was designed for the first time. The volatile monoterpenes in Mentha haplocalyx Briq were extracted using this method from a solution containing plant solid particles as the lower phase of solvent sublation. Under the optimum conditions of the solvent sublation (n-hexane/plant solid particles 20% ethanol-water solution system, pH 4, flotation time 30 min and air flow rate 30 mL/min), the extraction yields were 2.0 × 102 mg/kg, 9.5 × 101 mg/kg and 1.2 × 103 mg/kg for menthone, isomenthone and menthol, respectively. Compared with the traditional methods, the established suspension particle assisted solvent sublation might be an economical and efficient extraction method in some aspects. Through a cellular antioxidant activity experiment, menthol could alleviate H2O2-induced oxidative stress. Molecular docking was applied to simulate the molecular recognition process between amyloid-β and menthol. The affinity energy of menthol was -12.59 kJ/mol, indicating that menthol might have neuroprotective activity and the potential to be an amyloid-β inhibitor.