title: Antioxidant activity and phenolic content of betalain extracts from intact plants and hairy root cultures of the red beetroot Beta vulgaris cv. Detroit dark red.
abstract: Betalains are water-soluble plant pigments that are widely used as food colorants, and have a wide range of desirable biological activities, including antioxidant, anti-inflammatory, hepatoprotective, anti-cancer properties. They can be produced from various plants, notably beetroot, but betalain products obtained in this way also have some undesirable properties and are difficult to standardize. A potentially attractive alternative is to use hairy root cultures. In the study reported here, we found that betalain extracts obtained from hairy root cultures of the red beetroot B. vulgaris cv. Detroit Dark Red also had higher antioxidant activity than extracts obtained from mature beetroots: six-fold higher 2,2-dyphenyl-1-picrylhydrazyl radical scavenging ability (90.7% inhibition, EC(50) = 0.11 mg, vs 14.2% inhibition, EC(50) = 0.70 mg) and 3.28-fold higher oxygen radical absorbance capacity (4,100 microM TE/g dry extract, vs 1,250 microM TE/g dry extract). The high antioxidant activity of the hairy root extracts was associated with increased concentrations (more than 20-fold) of total phenolic concomitant compounds, which may have synergistic effects with betalains. The presence of 4-hydroxybenzoic acid, caffeic acid, catechin hydrate, and epicatechin were detected in both types of extract, but at different concentrations. Rutin was only present at high concentration (1.096 mg.g(-1) dry extract) in betalain extracts from the hairy root cultures, whereas chlorogenic acid was only detected at measurable concentrations in extracts from intact plants.
authors.affiliation: Department of Microbial Biosynthesis and Biotechnologies, Laboratory in Plovdiv, The Stephan Angeloff Institute of Microbiology, Bulgarian Academy of Sciences, 139 Ruski Blvd., 4000, Plovdiv, Bulgaria.
authors.forename: Vasil Georgiev
authors.initials: VG
authors.lastname: Georgiev
authors.forename: Jost
authors.initials: J
authors.lastname: Weber
authors.forename: Eva-Maria
authors.initials: EM
authors.lastname: Kneschke
authors.forename: Petko Nedyalkov
authors.initials: PN
authors.lastname: Denev
authors.forename: Thomas
authors.initials: T
authors.lastname: Bley
authors.forename: Atanas Ivanov
authors.initials: AI
authors.lastname: Pavlov
mesh_terms: D000975:Antioxidants / Q000032:analysis / Q000494:pharmacology*; D027461:Beta vulgaris / Q000737:chemistry*; D050858:Betalains / Q000302:isolation & purification / Q000494:pharmacology*; D018929:Cell Culture Techniques; D010636:Phenols / Q000032:analysis / Q000494:pharmacology*; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D018517:Plant Roots / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D010636:Phenols; D010936:Plant Extracts; D050858:Betalains