Some biological activities of ethanol extract of Amaranthus lividus L. seeds and isolation of the lectin from the crude extract

Abstract

Background and Aims: Amaranth is a gluten-free pseudocereal with nutraceutical properties. The aim of this study was to evaluate the antioxidant, anti-cholinergic and cyclooxygenase (COX) inhibitory effects of the ethanol extract and isolate the lectin from the crude extract prepared from seeds of Amaranthus lividus L. Methods: The dried powdered seeds were extracted with ethanol using a Soxhlet apparatus. The antioxidant activity of the ethanol extract was estimated by DPPH, ABTS and superoxide radical scavenging activities, as well as the Trolox equivalent antioxidant capacity (TEAC) and Ferric-Reducing Antioxidant Power (FRAP). The total phenolic compound content was determined using the Folin-Ciocalteu reagent. The extract was screened for its acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibitory activities using Ellman’s method. The ability of the extracts to inhibit COX-1 and COX-2 was determined by enzyme immunoassay. The lectin was purified from the crude extract by a two-step procedure of 50% ammonium sulphate precipitation and affinity chromatography on CNBr-activated Sepharose 4B, using ovalbumin as a ligand. The molecular weight was determined using SDS-PAGE. Results: Results showed that the extract possesses in vitro antioxidant, AChE, BuChE, COX-1 and COX-2 inhibitory activities, suggesting that it may provide treatment options for oxidative stress mediated diseases like Alzheimer’s, inflammatory and cancer diseases. The crude extract of the A. lividus seeds was found to contain lectin, evident by hemagglutination. The lectin was purified to homogeneity approximately 16-fold over the crude extract. It was determined to be a homodimer, and the molecular weight of the monomer corresponded to 34 kDa. Conclusion: The results showed that the seeds of A. lividus contain valuable ingredients such as phenolic compounds and lectin that are beneficial for health.