Composition analysis and antioxidant activity of essential oils, lipids and polysaccharides in different phenotypes of Lepidium meyenii.

The phenotypes of Lepidium meyenii (Maca) relate to their difference of chemical compositions and biological activities. Essential oils, lipids and polysaccharides are the main active components in Maca, all of which showed potential antioxidant effect. The essential oil, lipid and polysaccharide compositions were analyzed by GC-MS after the samples were properly pre-treated from yellow, red and black Maca. The antioxidant properties of the three types of components were examined using the DPPH scavenging assay. The correlation of main compositions and the antioxidant activities was evaluated by a statistical method. In Maca essential oil, lipid and polysaccharide samples, thirty volatile compounds, twenty-nine fatty acids and six monosaccharides had been detected, in which benzeneacetonitrile, unsaturation fatty acids and mannose were predominant ingredients, respectively. In three types of components, the DPPH scavenging effect of essential oil was stronger. All of black Maca essential oil, lipid and polysaccharide showed higher effect than yellow and red phenotype. The total activity of the three types of components showed about 60% of the antioxidant activity of entire Maca. Canonical correlation analysis (CCA) results showed that four essential oils, three fatty acids and four monosaccharaides were positively related to the antioxidant activity. The research is helpful to address the quality attributes and the comprehensive application of different phenotypes of Maca.