# Tart Cherry (Prunus cerasus) Extract Exerts High Intracellular ROS Scavenging Activity and Repression of ARE (Antioxidant Response Element) Pathway in Human Hepatocytes

## TL;DR

Tart cherry extract effectively reduces harmful molecules inside liver cells but also suppresses a key antioxidant pathway.

## Contribution

The study reveals tart cherry extract's dual action as a strong ROS scavenger and an inhibitor of the ARE pathway in human liver cells.

## Key findings

- Tart cherry extract shows high intracellular ROS scavenging activity with an EC50 of 72.02 µg/mL.
- The extract represses ARE-driven transcriptional activity, reducing luciferase gene expression by up to 70%.
- Antioxidant efficacy at the cell membrane is much lower compared to intracellular activity.

## Abstract

Polyphenol-rich fruits represent promising natural candidates for mitigating oxidative stress. We determined in dose–response manner the intracellular antioxidant activities of P. cerasus (tart cherry) extract in HepG2 cells using three different cellular assays targeting specific mechanisms of action: (1) the AOP1 assay, to assess intracellular ROS scavenging activity; (2) the CAA assay, to estimate ROS scavenging activity at the cell membrane; and (3), the HepG2-ARE-luc assay, to evaluate Antioxidant Response Element (ARE) pathway modulation. Tart cherry extract exhibited a high and concentration-dependent intracellular ROS scavenging activity with the AOP1 assay (EC50 of 72.02 µg/mL), whereas antioxidant efficacy measured via the CAA assay was much lower (EC50 of 6.975 mg/mL). Notably, P. cerasus extract did not activate the ARE-driven luciferase gene expression. Instead, the extract induced a clear dose-dependent repression of ARE-driven transcriptional activity, with a reduction in luciferase gene expression ranging from 20 to 70% across the sample tested concentrations (0.38–98 µg/mL). These findings suggest that, at concentrations where it functions as a potent intracellular ROS scavenger, P. cerasus extract exerts a negative regulation of the ARE pathway. Further investigations are warranted to elucidate the compounds underlying these effects.