Red chicory (Cichorium intybus L. cultivar) as a potential source of antioxidant anthocyanins for intestinal health

Abstract

Fruit- and vegetable-derived foods have become a very significant source of nutraceutical phytochemicals. Among vegetables, red chicory (Cichorium Intybus L. cultivar) has gained attention for its content of phenolic compounds, such as the anthocyanins. In this study, we evaluated the nutraceutical effects, in terms of antioxidant, cytoprotective, and antiproliferative activities, of extracts of the whole leaf or only the red part of the leaf of Treviso red chicory (a typical Italian red leafy plant) in various intestinal models, such as Caco-2 cells, differentiated in normal intestinal epithelia and undifferentiated Caco-2 cells. The results show that the whole leaf of red chicory can represent a good source of phytochemicals in terms of total phenolics and anthocyanins as well as the ability of these phytochemicals to exert antioxidant and cytoprotective effects in differentiated Caco-2 cells and antiproliferative effects in undifferentiated Caco-2 cells. Interestingly, compared to red chicory whole leaf extracts, the red part of leaf extracts had a significantly higher content of both total phenolics and anthocyanins. The same extracts effectively corresponded to an increase of antioxidant, cytoprotective, and antiproliferative activities. Taken together, these findings suggest that the red part of the leaf of Treviso red chicory with a high content of antioxidant anthocyanins could be interesting for development of new food supplements to improve intestinal health.

Figure 1

Antioxidant activity of WL and RL extracts of Treviso red chicory in Caco-2 cells differentiated in normal intestinal epithelia. The cells were treated with various concentrations of extracts for 4 h and then treated with t-BuOOH (0.5 mM) for 30 min. At the end of incubation, intracellular ROS formation was determined using a fluorescence probe, DCFH-DA, as described in the Materials and Methods section. The values are expressed as percentage of increase of intracellular ROS formation evoked by exposure to t-BuOOH. The values are shown as mean ± SD of four independent experiments (*P < 0.05, **P < 0.01 versus untreated cells, at ANOVA with Dunnett's Post Hoc Test; °P < 0.05 versus cells treated with WL extracts at Student's t-test).

Figure 2

Cytoprotective activity of WL and RL extracts of Treviso red chicory in Caco-2 cells differentiated in normal intestinal epithelia. The cells were treated with various concentrations of extracts for 4 h and then treated with t-BuOOH (0.5 mM) for 24 h. At the end of incubation, cytotoxicity was determined using trypan blue assay as described in the Materials and Methods section. The values are expressed as percentage of cell viability after exposure to t-BuOOH. The values are shown as mean ± SD of four independent experiments (*P < 0.05, **P < 0.01 versus untreated cells, at ANOVA with Dunnett's Post Hoc Test; °P < 0.05 versus cells treated with WL extracts at Student's t-test).

Figure 3

Effects of WL and RL extracts of Treviso red chicory on TAA of membrane (a) and cytosolic (b) fractions of Caco-2 cells differentiated in normal intestinal epithelia. The cellular fractions were submitted to the ABTS methods after 4 h of incubation with various concentrations of extracts as described in Section 2. The results obtained for each cellular fraction sample were expressed as μmol of TEAA per mg of protein. The values represent the mean ± SD of three independent experiments (*P < 0.05, **P < 0.01 versus untreated cells at ANOVA with Dunnett's Post Hoc Test; °P < 0.05 versus cells treated with WL extracts at Student's t-test).

Figure 4

Effects of WL and RL extracts of Treviso red chicory on cell proliferation of undifferentiated Caco-2 cells. The cell proliferation was determined by the MTT assay after 96 h of incubation with various concentrations of extracts. The results were expressed as a percentage of control cells. The values represent the mean ± SD of three independent experiments (**P < 0.01 versus cells treated with WL extracts at Student's t-test).