Evaluation of immunomodulatory properties of phenolic extracts from olive mill by-products using Caco-2 cells and molecular docking analysis

The bioactive potential of phenolic extracts derived from olive mill solid by-product (OMSbP), also called alperujo, and olive mill water (OMW), remains a topic of significant interest due to the amount of these, especially in Mediterranean regions, and their potential health benefits. In this study, the antioxidant and immunomodulatory properties of phenolic extracts obtained from OMSbP and OMW (OMSbP-P and OMW-P, respectively) in intestinal cells were evaluated. Initially, phenol-rich extracts were prepared by ethanol/ethyl acetate extraction and were characterized by HPLC-DAD analyses. The in vitro antioxidant activity showed potent bioactivities for all extracts evaluated. Toxicity assays did not reveal adverse effects on Caco-2 cell viability at concentrations relevant to immunomodulatory activity. Subsequently, the immunomodulatory effects of these extracts were assessed by measuring gene expression of pro- and anti-inflammatory cytokines. The results demonstrate that both OMSbP-P and OMW-P exhibit significant immunomodulatory activities, as evidenced by modulated cytokine gene expression in intestinal cells. Furthermore, molecular docking analyses of the identified phenols with the TLR4/MD2 receptor showed binding affinity, increasing the evidence that these extracts could exert immunomodulatory activity. Overall, our findings suggest that OMSbP-P and OMW-P possess promising immunomodulatory properties in intestinal cells, thus emphasizing their potential as natural therapeutic agents for managing immune-related disorders and promoting gut health. Further elucidation of the molecular mechanisms underlying these effects and in vivo studies are warranted to fully exploit the therapeutic potential of these extracts.