In Vitro antioxidant and antimicrobial activities of Lignan flax seed extract (Linumusitatissimum, L.)

Abstract

Flaxseed is one of dietary sources contain considerable amount of phenolics namely lignan. The aim of this study was to evaluate the potential activities of lignan extracts as a potential source of antioxidant and antimicrobial agents. Five flaxseed cultivars namely (Amon, Blanka, Lithuania, Sakha1 and Teka) were studied. DPPH . scavenging activity and Fe 2+ -chelating were studied at the different concentrations of lignan extract from 5µg/ml to 50 µg/ml. Lithuania cultivar revealed the highest inhibition % against the stable free radical DPPH (9.05 to 88.56 %) compared with butylated hydroxy toluene (BHT) as standard agent (40.31 to 93.94 %). In addition, lignan extracts of all flaxseed cultivars also showed highly Fe 2+ -chelating antioxidant power especially Lithuania and Teka cultivars. Identification of lignan extract by HPLC showed the presence of many phenolic compounds (p-coumaric acid (CouA), 5hydroxylmethyl-2-furfural (HMF), ferulic acid (FerA) and secoisolariciresinoldiglucoside (SDG) in variables levels. SDG was found as the most abundant constituent of lignan extract in all cultivars of flaxseed. Maximum antimicrobial activity was observed with ethanolic extract of Lithuania against Gram negative bacteria, whereas, ethanolic extract of Teka had antibacterial effect against Gram positive bacteria. All extracts were inactive against A. niger, and C. albicans. The MIC values were ranged from (224 to 488µg/ml). Amon and Blanka cultivars displayed a highest MIC value (366 and 348µg/ml) against Gram negative and (488 and 464 µg/ml) against Gram positive, respectively. While, Lithuania cultivar showed the lowest MIC (224 µg/mL) for each microorganism. These results are considered as most important and promising finding in pharmaceutical properties of lignans.