Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/16/2005
Publication Date: 1/15/2006
Citation: Wu, X., Pittman, H.E., Prior, R.L. 2006. Fate of anthocyanins and antioxidant capacity in contents of the gastrointestinal tract of weanling pigs following black raspberry consumption. Journal of Agricultural and Food Chemistry. 54(1):583-589.
Interpretive Summary: Many fruits/berries are rich in anthocyanins, which are the pigments that give the dark blue/red colors to berries. Anthocyanins have high antioxidant capacity, but due to their apparent low absorption, their possible roles in health promotion in vivo are still in question. The objectives of these studies were to determine the fate of anthocyanins within the gastrointestinal tract and the effect on the absorption and subsequent metabolism of anthocyanins. Weanling pigs were used as an animal model in this study since the pig seems to handle these components similarly to the human. Recovery of anthocyanins within the gastrointestinal tract was positively and linearly associated with urinary anthocyanin recovery. The environment of different segments of the gastrointestinal tract clearly determines the stability of individual anthocyanins. Anthocyanins with complex chemical structures were observed to be more stable in the gastrointestinal tract than simple anthocyanins. Anthocyanins were shown to provide significant antioxidant protection in the environment of the gastrointestinal tract. This effect may have significant implications in the protection against the development of colon cancer.
Technical Abstract: Many fruits are rich in anthocyanins (ACNs). ACNs have high antioxidant capacity, but due to their apparent low bioavailability, their possible roles in health promotion in vivo are still in question. The objectives of these studies were to determine the fate of ACNs within the gastrointestinal GI tract and the effect on the bioavailability and subsequent metabolism of ACNs. Five weanling pigs (16.3 +/- 5.9 kg) were fed freeze-dried black raspberry powder by oral administration which provided 1146.1 +/- 44.6 umol TE total ORACFL per kg and 50.5 +/- 3.7 mg per kg total ACNs. After 4 h, the pigs were sacrificed and the contents of five GI segments [duodenum, jejunum, ileum, cecum and colon] were collected and analyzed for their total antioxidant capacity (TAC, measured as ORACFL) and ACNs. The recoveries of TAC and total ACNs were 46.5 +/- 3.5% and 41.7 +/- 4.9%, respectively. Both total ACNs and TAC were recovered primarily in the ileum, cecum, and colon at 4 h after a meal. Cyanidin aglycone with different sugar moieties showed significant differences in their recovery within the GI tract with sambubiose > -sambubiose-rhamnose = rutinose >> glucose. Recovery of ACNs within the GI tract was positively and linearly associated with urinary ACN recovery. The environment of different segments of the GI tract clearly determines the stability of individual ACNs. Complex ACNs containing di- or tri-glycosides were observed to be more stable in the GI tract than simple ACNs as a monoglucoside. TAC and total ACNs remained high after 4 h after feeding, which indicates that ACNs provide significant antioxidant protection in the environment of the gut epithelium.