Potential antitumor properties of a protein isolate obtained from the seeds of Amaranthus mantegazzianus

Why it matters

According to the researchers, the nutritional composition of the amaranth grain has been extensively studied, especially with regard to its high quality and quantity of protein. The amino acid composition of the grain proteins are similar to the optimum balance required in the human diet. In addition, these proteins have a variety of physical and chemical properties that would point to the amaranth as providing a potential new raw material for incorporation into a novel functional food. In recent years, antitumor activity has been reported in the leaves of the plant Amaranthus tricolor. Several bioactive peptides have been detected in Amaranthus hypochondriacus through the use of bioinformatics tools. At the moment, the only lunasin-like peptide with potential antitumor properties has been found in Amaranthus hypochondriacus storage proteins. This work constituted the first research report of an antiproliferative activity in Amaranthus mantegazzianus-protein isolate, and presented its putative mechanism of action on different tumor and nontumor cell lines in vitro.

Reference

The article appears in the March 2010 issue of the International Journal of Food Microbiology (volume138, issues 1-2, pages 1-12). Authors: Daniel Alejandro Barrio & María Cristina Añón.

Abstract

Amaranth is a crop that can be grown in different soils and climates, being resistant to high temperatures, drought, and some pests. The amaranth plant has nutritional qualities and desirable biological properties. The aim of the study is to investigate the potential antitumor properties of Amaranthus-mantegazzianus-protein isolate (MPI) and to elucidate the possible mechanism of action. We use four different tumor-derived and in vitro-transformed cell lines with different morphology and tumorigenicity (MC3T3E1, UMR106, Caco-2, and TC7). The MPI showed an antiproliferative effect on four cell lines with different potencies. The tumor-cell line UMR106 was the most sensitive (IC₅₀: 1 mg/ml). This antiproliferative effect of the MPI was enhanced by protease treatment (IC₅₀: 0.5 after 30% hydrolysis). In addition, the MPI produced morphological changes and caused a rearrangement of the cytoskeleton in UMR106 cell line. In an attempt to elucidate the mechanism of action, we observed that the MPI inhibited cell adhesion and induced apoptosis and necrosis in the UMR106 cell line. In reversibility studies, we were able to observe both temporary and permanent cytostatic and cytotoxic effects on the part of the MPI, depending on its concentration. We report a protein isolate from the seeds of Amaranthus mantegazzianus that exhibit potential antitumor properties and propose a putative mechanism of action.