In vitro digestion, absorption and biological activities of acylated anthocyanins from purple sweet potatoes (Ipomoea batatas).

Purple sweet potatoes (PSP) are widely used as color enhancers in food formulations. Investigations on the stability of PSP polyphenolics during simulated digestion and subsequent absorption in a Caco-2 cell monolayer model were accomplished. Measures of bioactive activities were also assessed in vitro. PSP whole polyphenolic extracts as a control (WC) were compared to isolates enriched in anthocyanins (AC) or non-anthocyanin phenolics (NAP). Anthocyanins were also alkali-hydrolyzed to remove acylated moieties. Compounds were subjected to simulated gastro-intestinal digestions where non-hydrolyzed anthocyanins showed higher stability compared to alkali-hydrolyzed. For many alkali-hydrolyzed anthocyanins, the transport through a Caco-2 cell monolayer was reduced. PSP fractions significantly increased the generation of reactive oxygen species in HT-29 cells and was suppressive in the CCD-18Co cells while down-regulated mRNA expression of inflammatory markers. Results indicate the importance of PSP composition and the effects of acyl moieties on anthocyanin stability and functional properties for food colors.

Overtraining is associated with DNA damage in blood and skeletal muscle cells of Swiss mice.

BACKGROUND: The alkaline version of the single-cell gel (comet) assay is a useful method for quantifying DNA damage. Although some studies on chronic and acute effects of exercise on DNA damage measured by the comet assay have been performed, it is unknown if an aerobic training protocol with intensity, volume, and load clearly defined will improve performance without leading to peripheral blood cell DNA damage. In addition, the effects of overtraining on DNA damage are unknown. Therefore, this study aimed to examine the effects of aerobic training and overtraining on DNA damage in peripheral blood and skeletal muscle cells in Swiss mice. To examine possible changes in these parameters with oxidative stress, we measured reduced glutathione (GSH) levels in total blood, and GSH levels and lipid peroxidation in muscle samples. RESULTS: Performance evaluations (i.e., incremental load and exhaustive tests) showed significant intra and inter-group differences. The overtrained (OTR) group showed a significant increase in the percentage of DNA in the tail compared with the control (C) and trained (TR) groups. GSH levels were significantly lower in the OTR group than in the C and TR groups. The OTR group had significantly higher lipid peroxidation levels compared with the C and TR groups. CONCLUSIONS: Aerobic and anaerobic performance parameters can be improved in training at maximal lactate steady state during 8 weeks without leading to DNA damage in peripheral blood and skeletal muscle cells or to oxidative stress in skeletal muscle cells. However, overtraining induced by downhill running training sessions is associated with DNA damage in peripheral blood and skeletal muscle cells, and with oxidative stress in skeletal muscle cells and total blood.