Detection of adulteration in dietary supplements: Maca (Lepidium meyenii) case study by NMR approach

Adulteration of dietary supplements has been a potential safety concern for consumers and regulatory agencies. Maca, Lepidium meyenii Walpers (Brassicaceae), is a perennial herbaceous plant grown on the high Andean plateaus. Its small turnip-like root has been used as aphrodisiac, energizer, and fertility enhancer, and is so-called a natural Viaga or Peruvian ginseng. In recent years, Maca products have gained increasing popularity throughout the world, and the demand and price have increased dramatically. The global supply shortage of maca plant material has made it prone to be a seriously adulterated dietary supplement. In the present study, a nuclear magnetic resonance (NMR) spectroscopic method was developed to assess the quality of maca products sold on the market. The method can be used as a rapid preliminary tool for detection of maca adulteration.