Anthocyanin characterization and bioactivity assessment of a dark blue grained wheat (Triticum aestivum L. cv. Hedong Wumai) extract Chun Hu a , Yi-Zhong Cai b , Wende Li c , Harold Corke b , David D. Kitts a, * a Food, Nutrition and Health, Faculty of Land and Food Systems, University of British Columbia, 2205 East Mall, Vancouver, BC, Canada V6T 1Z4 b Department of Botany, The University of Hong Kong, Hong Kong c Cereal Chemistry and Quality Analysis Laboratory, Faculty of Chemistry and Chemical Engineering, Shanxi University, China Received 28 September 2006; received in revised form 8 December 2006; accepted 20 December 2006 Abstract Defatted bran of dark blue grained wheat (Triticum aestivum L., cv. Hedong Wumai) was extracted using ethanol and chemically characterized by HPLC and ESI-MS. Cyanidin-3-glucoside was the predominant anthocyanin in the pigmented wheat which also con- tained cyanidin-3-galactoside, pelargornidin-3-glucoside, and peonidin-3-glucoside. Ferulic acid was identified as the major simple phe- nolic acid, with lesser amounts of p-hydroxybenzoic acid, caffeic acid, syringic acid and p-coumaric acid also present. Anthocyanins were separated from phenolic acids using solid phase extraction, and respective fractions were determined for DPPH radical, ABTS radical scavenging tests as well as oxygen radical absorption assay. Results showed that 69% of the overall free radical scavenging capacity of dark blue grained wheat was attributed to the anthocyanin content, compared to 19% for the extractable phenolic acids. In cell based models, the pigmented wheat extract significantly suppressed both hydrogen peroxide-induced intracellular oxidation (p < 0.01) and bac- terial lipopolysaccharide-induced nitric oxide (p < 0.05) production. These data report for the first time the major phytochemical com- position of pigmented grained wheat and associated bioactivity towards free radical scavenging and suppression of ROS and RNS activity. Crown Copyright Ó 2007 Published by Elsevier Ltd. All rights reserved. Keywords: Dark blue wheat; Anthocyanin; Phenolic acid; Reactive oxygen species; Reactive nitrogen species 1. Introduction Antioxidant properties of cereals have been reported in pigmented rice (Hu, Zawistowski, Ling, & Kitts, 2003), wheat (Li, Shan, Sun, Corke, & Beta, 2005; Zhou, Laux, & Yu, 2004) and purple corn (de Pascual-Teresa, Santos- Buelga, & Rivas-Gonzalo, 2002). Free radical scavenging capacity of black sorghum has been attributed to the pres- ence of 3-deoxyanthocyanin (Awika, Rooney, & Waniska, 2004). Other workers have reported that ferulic acid (Li et al., 2005; Zhou, Yin, & Yu, 2005) along with tocopherol and carotenoids (Zhou et al., 2005) were responsible for the antioxidant properties of hard red winter wheat bran. A steryl ferulate extract collected from wheat bran has also been shown to protect methyl linoleate from thermal autoxidation (Nystrom, Makinen, Lampi, & Piironen, 2005). Moreover, recent data has indicated the possibility of underestimating the total antioxidant capacity of cereals due to the existence of unextractable phenolic complexes (Pearez-Jimeanez & Saura-Calixto, 2005). Analysis of the phytochemical profiles of different wheat varieties indicates little variation in total phenolic acid and total antioxidant activity, but significant differences are present in total feru- lic acid and carotenoid content (Adom, Sorrells, & Liu, 2003). However, the anthocyanin composition of pig- mented wheat is not well characterized (Escribano-Bailon, Santos-Buelga, & Rivas-Gonzalo, 2004). 0308-8146/$ - see front matter Crown Copyright Ó 2007 Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.foodchem.2006.12.064 * Corresponding author. Tel.: +1 604 822 5560; fax: +1 604 822 5143. E-mail address: ddkitts@interchange.ubc.ca (D.D. Kitts). www.elsevier.com/locate/foodchem Food Chemistry 104 (2007) 955–961 Food Chemistry