Methanol extracts from the plant were found to be similar in antioxidant activity to the established antioxidants ascorbic acid, alpha-tocopherol, and BHT, according to findings published in the Journal of Agricultural and Food Chemistry.
“Because the most active and abundant phenols are common constituents of plant foods, the results of this study showed that the methanol root extract of this plant could be used as a source of natural antioxidants useful as potential food additives,” wrote lead Antonio Fiorentino from the Seconda Universita degli Studi di Napoli.
Interest is growing in plant-derived food additives as replacements to synthetic antioxidants like butylhydroxyanisole (BHA) and butylhydroxytoluene (BHT) to slow down the oxidative deterioration of food.
Indeed, according to Frost and Sullivan, the synthetic antioxidant market is in decline, while natural antioxidants, such as herb extracts (particularly rosemary), tocopherols (vitamin E) and ascorbates (vitamin C) are growing, pushed by easier consumer acceptance and legal requirements for market access.
Fiorentino and co-workers used methanol to prepare extracts from the roots of C. distachya. Using the DPPH (2,2-diphenyl-1-picrylhydrazyl) radical-scavenging test to quantify antioxidant activity, the researchers report a value similar to those obtained from alpha-tocopherol, ascorbic acid, and BHT.
Indeed, the antioxidant activity value quoted by the researchers following the DPPH test was 4.2 micrograms per millilitre for the sedge extract, which compared to 4.3, 5.1, and 3.9 micrograms per millilitre for ascorbic acid, alpha-tocopherol, and BHT, respectively.
Using a range of spectroscopic techniques, 16 polyphenols were identified, including seven lignans, four phenylethanoids, three resveratrol derivatives, a secoiridoid glucoside, and a monolignol.
“These results revealed a strong antioxidant activity because of the presence of an extraordinary quantity of bioactive phytochemicals,” wrote Fiorentino and co-workers.
Indeed, the researchers highlight the resveratrol derivatives as a key contributor to the high antioxidant activity.
“Because resveratrol and its oligomers from Vitis Vinifera have been demonstrated to be powerful antioxidants and bone-health phytochemicals, their discovery in other sources has been extensively investigated,” they stated.
Source: Journal of Agricultural and Food ChemistryVolume 56, Issue 17, Pages 8218–8225, doi: 10.1021/jf801603s "Potential Food Additives from Carex distachya Roots: Identification and in Vitro Antioxidant Properties"Authors: A. Fiorentino, A. Ricci, B. D’Abrosca, S. Pacifico, A. Golino, M. Letizia, S. Piccolella, P. Monaco