Bioactive peptides in amaranth (Amaranthus hypochondriacus) seed

Area of Science:

• Plant biochemistry
• Nutritional science
• Molecular biology

Background:

• Amaranth seeds are a valuable protein source, but their bioactive peptide content remains largely uncharacterized.
• Understanding these compounds is crucial for leveraging amaranth's full health potential.

Purpose of the Study:

• To identify and characterize the peptide lunasin in amaranth seeds.
• To investigate the anticarcinogenic activity of amaranth-derived peptides.
• To predict other bioactive peptides within amaranth protein fractions.

Main Methods:

• Enzyme-linked immunosorbent assay (ELISA) for lunasin quantification.
• Western blot and MALDI-TOF mass spectrometry for peptide identification and characterization.
• In vitro apoptosis assays using HeLa cells.
• Bioinformatic tools for peptide prediction.

Main Results:

• Lunasin was detected in four amaranth genotypes at an average concentration of 11.1 microg/g.
• The glutelin fraction showed the highest lunasin concentration (3.0 microg/g).
• A lunasin-like peptide, sharing over 60% sequence similarity with soybean lunasin, was identified.
• Amaranth glutelin extracts induced apoptosis in HeLa cancer cells.
• Predicted bioactive peptides were primarily antihypertensive.

Conclusions:

• Amaranth seeds contain a lunasin-like peptide with demonstrated anticarcinogenic properties.
• This study provides the first evidence of bioactive peptides, including lunasin, in amaranth protein fractions.
• Amaranth represents a promising source of peptides with potential health benefits, including anticancer and antihypertensive activities.