**3. Materials and Methods**

#### *3.1. Materials*

*Lepidium meyenii* was provided by Changchun University of Chinese Medicine and a voucher specimen (No. 201710) was deposited at the laboratory of Jilin Ginseng Academy, Changchun University of Chinese Medicine, P.R. China. Mouse leydig cells (TM3) were purchased from the Cell Bank of Type Culture Collection Chinese Academy of Sciences (Shanghai, China; cat. no. GNM24).

Standard compounds *N*-benzyl-hexadecanamide, *N*-benzyl-(9z,12z)-octadecadienamide and *N*-benzyl-(9z,12z,15z)-octadecatrienamide were provided by Yunnan Technical Center for Quality of Chinese Materia Medica (Yunnan, China). All standards were of purity greater than 98% and suitable for HPLC/MS/MS analysis.
