Chemical and biological study of the seeds of Eragrostis tef (Zucc.) Trotter

Abstract

A chemical study of the red type of the seeds of Eragrostis tef (Zucc.) Trotter (Poaceae) led to the isolation of seven compounds from its ethanol extract, namely β-sitosterol (1), β-amyrin-3-O-(2'-acetyl(glucoside (2), β-sitosterol-3-O-β-D-glucoside (3), naringenin (4), naringenin-4'-methoxy-7-O-α-L-rhamnoside (5), eriodictyol-3',7-dimethoxy-4'-O-β-D-glucoside (6) and isorhamnetin-3-O-rhamnoglucoside (7), which are reported for the first time in the genus Eragrostis. This is the first report for the isolation of compounds (2) and (6) in nature. The isolated compounds were identified using different spectroscopic methods (EIMS, UV, ¹H NMR, ¹³C NMR, HMQC and HMBC). A proximate analysis revealed the high nutritive value of the seeds: carbohydrates (57.27%), protein (20.9%), essential amino acids (8.15%) with major leucine and lysine (1.71 and 1.35%, respectively), vitamin B₁ (1.56 mg/100 g) and potassium and calcium (32.4 and 9.63%, respectively). The seeds yielded 22% w/w of fixed oil rich in unsaturated fatty acids (72.46%), among which oleic acid, was predominant (32.41%), followed by linolenic acid (23.83%). The ethanolic extract and fixed oil of the seeds exhibited anti-hyperlipedaemic and anti-hyperglycaemic activities. Oral administration of the fixed oil for 10 days resulted in a rise in serum calcium levels in rats.

Teff (Eragrostis tef) as a raw material for malting, brewing and manufacturing of gluten-free foods and beverages: a review

“…Teff grains are rich in unsaturated fatty acids. The seeds contain 22 % w/w of fixed oil rich in unsaturated fatty acids (72.46 %), among which oleic acid is predominant (32.41 %), followed by linoleic acid (23.83 %) (El-Alfy et al 2011). The unsaturated fatty acids are not only important for our nutrition, especially as some cannot be synthesized by humans (essential fatty acids), but also play important role in the production of beer.…”

Teff: Suitability for Different Food Applications and as a Raw Material of Gluten-free, a Literature Review

“…A proximate analysis revealed the high nutritive value of the seeds of Eragrostis tef: carbohydrates (57.27%), protein (20.9%), essential amino acids (8.15%) with major leucine and lysine (1.71 and 1.35%, respectively), vitamin B1 (1.56%) and potassium and calcium (32.4 and 9.63%, respectively). The seeds yielded 22% w/w of fixed oil rich in unsaturated fatty acids (72.46%), among which oleic acid, was predominant (32.41%), followed by linolenic acid (23.83%) [22]. The grain proteins are also presumed easily digestible because prolamins are very small [20].…”

“…A chemical study of the red type of the seeds of Eragrostis tef led to the isolation of seven compounds from its ethanol extract, namely β-sitosterol (1), β-amyrin- (6) and isorhamnetin-3-O-rhamnoglucoside (7), which are reported for the first time in the genus Eragrostis [22].…”

Antioxidant and Neuroprotective Activity of the Aerial Parts of Seven Eragrostis Species and Bioactive Compounds from E. japonica

“…However, it remains unknown whether these compounds are present in other Eragrostis species, therefore, further studies are required to isolate and identify the potentially antioxidant or neuroprotective compounds in other Eragrostis species. Eragrostis Wolf is the largest genus within the subfamily Chloridoideae of the Poaceae and has about 350 species, of which only 3 species have been studied for flavonoids: E. ferruginea, E. curvula and E. tef [5,[20][21]. These 3 species showed different flavonoids profiles except tricin.…”

“…E. ferruginea has been reported to contain 7-demethylageconyflavone A, ageconyflavone A and tricin [5]. E. curvular contained tricin and violanthin [20] and E. tef has been shown to contain naringenin, naringenin-4'-methoxy-7-Orhamnoside, eriodictyol-3', 7-dimethoxy-4'-O-glucoside and isorhamnetin-3-O-rhamnoglucoside [21]. The isolated flavonoids of E. japonica also differ from the species in that it only contained isoorientin and isovitexin.…”