Capacity of chlorogenic acid isomers to modulate oxidative and inflammatory responses in Caco‐2 human enterocyte‐like cells
Bibliographic record
Abstract
Chlorogenic acids (CGAs) are esters formed between caffeic and quinic acids, and represent an abundant group of plant polyphenols present in the human diet. CGAs contain different isomers, including the major ones such as 5‐caffeoylqunic acid (5‐CQA), 3‐caffeoylqunic acid, 4‐caffeoylqunic acid, 3,4‐dicaffeoylqunic acid, 3,5‐dicaffeoylquinic acid, and 4,5‐dicaffeoylqunic acid. The antioxidant and anti‐inflammatory properties of 5‐CQA have been established in both cell and animal studies. However, little is known about the ability of other major CGA isomers to modulate oxidative and inflammatory stresses. In this study, we conducted a pre‐treatment experiment in which Caco‐2 cells were exposed to individual physiological relevant concentrations of CGA isomers for 24 hours and once removed were then challenged with oxidative and inflammatory stresses. We found that the pre‐incubation of CGA isomers promoted pro‐inflammatory cytokine, interleukin 8, and activated the nuclear translocation of nuclear factor kappa B (NF‐κB) pathway. The pre‐incubation did not activate nuclear factor‐E2‐related factor 2 (Nrf2) pathway. A co‐incubation experiment was conducted in which Caco‐2 cells were firstly exposed to individual CGA isomers for 24 hours. Then, fresh CGA isomers were added before cells were challenged with oxidative and inflammatory stresses. Herein, we found that the co‐incubation treatment of CGA isomers showed anti‐inflammatory effect by attenuating the secretion of IL‐8. This was accompanied with an increase in NF‐κB signaling. We also found that CGA co‐incubation treatment significantly increased Nrf2 signaling that corresponded to increased ratio of reduced glutathione to oxidized glutathione; both indicating a mitigated oxidative stress. We proposed that CGA isomers exert anti‐inflammatory activity by activating Nrf2 signaling, even though CGA isomer activated NF‐κB pathway at the early stage of response. Our results suggest that Nrf2 is a secondary event that participates in a later negative loop of NF‐kB regulation. Cross‐talk between NF‐κB and Nrf2 seems apparent in this case. Support or Funding Information This work was funded by the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".