Seperation and identification of bioactive compounds in Lepidium meyenii (Maca) based on the combination of medium-pressure liquid chromatography and preparative HPLC

Lepidium meyenii (Maca) has health benefits for relieving menopausal symptoms and improving sexual function [1]. The main bioactive components of Maca were unsaturated fatty acids and macamides [2]. The isolation of these bioactive components from Maca has been a challenge. In this work, the preparative separation of bioactive components was effective process with two steps: the preparation of fractions using medium-pressure liquid chromatography and the purification of components by the preparative HPLC. The 8 compounds in the Maca were obtained with the amount of 76 to 836 mg and of high purity (98%, HPLC) from the 200 g ethanol extracts. The chemical structures of these compounds were identified by HR-ESI-MS, ¹H and ¹³C NMR. To the best of our knowledge, ethyl linolenate and ethyl linoleate were separated from Maca for the first time. Besides, the HPLC method has also been developed to determine the contents of eight main bioactive components. Fig 1 is the typical HPLC chromatogram of ethanol extract of Maca. The HPLC conditions were: the column was Thermo ODS hypersil C18 (4.6 mm × 250 mm, 5 µm). The mobile phase was water-phosphoric acid-acetonitrile (200:1:800, v/v). The column temperature was 40 °C. The flow rate was 1.0 mL/min. The detection wavelength was 220nm. The results showed that the total eight bioactive components was about 1500 mg/100 g ethanol extracts and about 80 mg/100 g dried Maca roots. The preparation and analysis method proposed in the work could be applied for the quality control of Maca or Maca extracts from different origins.

Fig. 1: The HPLC chromatogram of ethanol extract of maca. 1. Linolenic acid. 2. N-benzyl-(9Z, 12Z, 15Z)-octadecatrienamide. 3. Linoleic acid. 4. N-(3-methoxybenzyl)-(9Z, 12Z)-octadecadienamide. 5. N-benzyl-(9Z,12Z)-octadecadienamide. 6. N-benzylhexadecanamide. 7. Ethyl linolenate. 8. Ethyl linoleate

References:

[1] Shin BC, Lee MS, Yang EJ, Lim HK, Ernst E. Maca (L. meyenii) for improving sexual function: a systematic review. BMC Complementary and Alternative Medicine 2010; 10: 44

[2] Zheng BL, He K, Kim CH, Rogers LL, Shao Y, Huang ZY, Lu Y, Yan SJ, Qien LC, Zheng QY. Effect of a lipidic extract from Lepidium meyenii on sexual behavior in mice and rats. Urology 2000; 55: 598 – 602