Detection of lunasin in quinoa (Chenopodium quinoa Willd.) and the in vitro evaluation of its antioxidant and anti-inflammatory activities.

BACKGROUND

Lunasin is a novel cancer-preventive peptide that has been detected in various plants. However, the presence and bioactivity of lunasin in quinoa have not been demonstrated.

RESULTS

Lunasin was detected in quinoa using ultrahigh-pressure liquid chromatography-electrosparay ionization-mass spectrometry. The content in 15 quinoa samples ranged from 1.01 × 10-3 g kg-1 dry seed to 4.89 × 10-3 g kg-1 dry seed. Significant differences (P < 0.05) in lunasin content among different cultivars (yy22, xsg86, xsg59, yy30 and yy19) from the same area and the same cultivar from different areas (Hainan, Hebei and Shanxi provinces) were observed. The lunasin isolated and purified from quinoa (QLP) exhibited a weak DPPH radical scavenging activity (no IC50 value), but a strong ABTS+ radical scavenging activity (IC50 value, 1.45 g L-1 ) and oxygen radical scavenging activity (40.06 µmol L-1 Trolox equivalents/g QLP when the concentration was 3.20 g L-1 ). In addition, QLP inhibited the production of nitric oxide (NO), tumor necrosis factor-α and interleukin-6 on lipopolysaccharide-stimulated RAW264.7 macrophages by up to 44.77%, 39.81% and 33.50%, respectively, at a concentration of 0.40 g L-1 .

CONCLUSIONS

Taken together, these findings indicate that lunasin presents in quinoa and is bioactive, which strengthens the recommendations for the development of quinoa-based functional foods. © 2017 Society of Chemical Industry.