# Procyanidin B2 and an autochthonous apple pulp extract modulate oxidative stress and PPARγ expression on an in vitro model of lipid steatosis in HepG2 cells

## TL;DR

This study shows that procyanidin B2 and an apple pulp extract reduce liver fat and oxidative stress in lab-grown liver cells, suggesting potential benefits for liver health.

## Contribution

The study demonstrates the protective effects of procyanidin B2 and an apple pulp extract on lipid accumulation and oxidative stress in HepG2 cells.

## Key findings

- Procyanidin B2 and Amarilla de Octubre apple pulp extract reduce fat accumulation in HepG2 cells overloaded with oleic acid.
- Both samples modulate the expression of PPARγ, CD36, and FAS genes related to lipid metabolism.
- Procyanidin B2 shows strong antioxidant and MAO-A inhibitory potential in vitro.

## Abstract

Metabolic dysfunction-associated steatotic liver disease (MASLD) is characterized by hepatic steatosis alongside metabolic comorbidities like type 2 diabetes mellitus (T2DM), dyslipidaemia, overweight, or obesity. Liver damage could be prevented promoting consumption of fruits and vegetables, the main source of phenolic compounds. These molecules have been previously related with antioxidant and anti-obesity properties. Therefore, the objective of this study is to determine the antioxidant capacity and potential preventive activity of an autochthonous apple pulp extract, Amarilla de Octubre, and its main phenolic compound, procyanidin B2 (PB2), in an in vitro model of liver steatosis. Antioxidant activity was assessed by xanthine/xanthine oxidase (X/XO) system and nitric oxide scavenging production. Monoamine oxidase A (MAO-A) inhibition was also determined due to its implication in detoxification processes in liver. Human hepatocytes (HepG2 cell line) were selected to test their potential cytotoxicity, oxidative stress situations (ROS production) and the potential effect in lipid metabolism by overloading cells with oleic acid. Fat accumulation and gene expression related to lipid metabolism (PPARγ, CD36 and FAS) were also analysed by Oil Red O and qPCR respectively. PB2 showed promising results as an antioxidant compound in scavenging and enzymatic inhibition-related experiments. However, Amarilla de Octubre not only reduce fat accumulation, but also modulates the expression of PPARγ, CD36, and FAS and demonstrates slightly lower efficacy than PB2 in scavenging and enzymatic inhibition-related experiments. These results highlight the potential of apples to mitigate pathogenic conditions associated with metabolic disorders such as obesity, emphasizing the role of dietary polyphenols in this protective effect.

The online version contains supplementary material available at 10.1007/s13105-026-01151-9.

The polyphenol procyanidin B2 exhibits strong antioxidant and MAO-A inhibitory potential, showing promising results for influencing the development of lipid accumulation in hepatocytes.

Procyanidin B2 and Amarilla de Octubre apple pulp extract protect human HepG2 hepatocytes from hydrogen peroxide-induced stress by attenuating intracellular ROS production.

The pulp extract from the Amarilla de Octubre apple reduces fat accumulation in oleic-acid overloaded HepG2 cells. Both tested samples, procyanidin B2 and the extract, modulate the expression of PPARγ, CD36, and FAS reducing their mRNA expression.

The online version contains supplementary material available at 10.1007/s13105-026-01151-9.