Green Pomegranate Waste Extract Modulates Macrophage Immunometabolism by Suppressing the ACLY-ME1 Axis and Promotes Pro-Resolving Macrophage Functions.

Background

Immunometabolic reprogramming is increasingly recognized as a fundamental driver of macrophage inflammatory activation. Although pomegranate polyphenols have been widely investigated for their anti-inflammatory activity, the underlying metabolic mechanisms remain poorly understood. Here, we investigated whether a pomegranate waste extract (PWE), obtained through a sustainable dimethyl carbonate (DMC)-based extraction process, modulates macrophage activation by targeting immunometabolic pathways.

Methods

Human PBMC-derived macrophages stimulated with LPS and IFN-γ were treated with PWE. Inflammatory mediators, NF-κB transcription factor, histone H3 acetylation, and markers of inflammatory resolution were evaluated. Furthermore, the enzymatic activity of ATP citrate lyase (ACLY) and malic enzyme 1 (ME1) was determined. Rescue experiments with acetate, malate, and NADPH were performed to investigate the functional contribution of the ACLY-ME1 metabolic axis.

Results

PWE significantly reduced NF-κB activation and the production of IL-1β, IL-6, TNF-α, ROS, NO•, and PGE2 without affecting cell viability. Mechanistically, PWE functionally suppressed ACLY and ME1, two central enzymes linking citrate metabolism to cytosolic acetyl-CoA and NADPH generation. Indeed, acetate supplementation restored PGE2 production and inflammatory cytokine secretion, whereas malate and NADPH rescued oxidative mediator production. PWE also lowered histone H3 acetylation, indicating that metabolic remodeling affected epigenetic regulation of inflammatory gene expression. Finally, PWE increased the expression of CPT1A, SLC25A20, Annexin A1, and FPR2, while enhancing IL-10 and 15-HETE secretion, consistent with activation of pro-resolving macrophage programs.

Conclusions

These findings demonstrate that DMC-extracted PWE suppresses inflammatory macrophage activation primarily through immunometabolic modulation. By targeting the ACLY-ME1 metabolic axis, PWE limits acetyl-CoA- and NADPH-dependent inflammatory processes and fosters a shift toward a pro-resolving macrophage phenotype. Our work identifies this sustainable pomegranate waste extract as a promising modulator of macrophage immunometabolism.