Nutritional composition of Eragrostis teff and its association with the observed antimutagenic effects

Abstract

Eragrostis teff is an Ethiopian native grass plant (Poaceae or Gramineae family) whose importance as a crop grain has increased in recent years. The aim of this study is to analyze the nutritional composition of its seeds and the mutagenic/antimutagenic activity of the hydroalcoholic extract of the seed flour. Chemical elements (colloquially known as minerals) were determined using Particle-Induced X-ray Emission (PIXE) and Flame Atomic Absorption Spectroscopy (FAAS), while the content of amino acids (aminogram) and fatty acids (profile of fatty acids) were quantified by HPLC. Mutagenic activities were tested using Salmonella/microsome assay. Mutagens doxorubicin, 4-nitroquinolin N-oxide, methylmethanosulphonate, and aflatoxin B-1 were used in Salmonella typhimurium TA98 and TA100 strains to assess antimutagenic activities. The major elements observed were K, P, S, Mg, and Ca. Almost all essential amino acids were observed and the predominance of unsaturated fatty acids in the total oil content of 2.72% (w/w) is also noted, including the two essential fatty acids alpha-linolenic acid (an omega-3 fatty acid) and linoleic acid (an omega-6 fatty acid). Hydroalcoholic extract of E. teff seed flour showed antimutagenic activity, protecting against frameshift and base pair substitution mutations. These findings provide valuable information for further development of healthier foods that can be produced with increasing yields and minimal environmental impact.

Fig. 1. Chromatogram of fluorescent derivatives formed by the reaction between free amino acids with NDA. Standard of amino acids (A) and a sample (B) from E. teff seed hydrolyzed proteins. Numbers above chomatographic peaks are referred to the following amino acids: (1) histidine; (2) arginine; (3) serine; (4) aspartic acid/asparagine; (5) glutamic acid/glutamine; (6) threonine; (7) glycine; (8) tyrosine; (9) alanine; (10) dl-2-aminobutyric acid (internal standard); (11) methionine; (12) valine; (13) phenylalanine; (14 + 15) leucine/isoleucine; (16) lysine.

Fig. 2. Chromatogram of fatty acid-MPAC-Br derivatives. Standard of fatty acids (A) and a sample (B). Samples of E. teff seed flour had the oils extracted and enzymatically hydrolyzed to deliver the fatty acids. These fatty acids were derivatized with MPAC-Br. The following fatty acids were found in the sample: C13:0, tridecanoic acid (internal standard, I.S.); C18:3, linolenic acid; C18:2, linoleic acid; C16:0, palmitic acid; C18:1, oleic acid; C18:0, stearic acid. Detection was performed with LIF at 405 nm.