Pomegranate Compound Shows Promise in Disrupting Transthyretin Amyloidosis

A natural compound found in pomegranate leaves and branches is demonstrating potential as a treatment for transthyretin amyloidosis (ATTR), a progressive disorder that can cause damage to the nerves and heart. Researchers at Kumamoto University in Japan have identified 1,2,3,4,6-penta-O-galloyl-β-D-glucose (PGG) as a molecule capable of dismantling the protein aggregates characteristic of the disease.

Understanding Transthyretin Amyloidosis

Transthyretin amyloidosis occurs when the transthyretin (TTR) protein, normally responsible for transporting thyroxine and retinol-binding protein in the blood, misfolds and forms insoluble amyloid fibrils. These fibrils deposit in organs like the heart and peripheral nerves, disrupting their normal function. [1]

Current Treatments and Their Limitations

Existing treatments for ATTR primarily focus on stabilizing the TTR protein to prevent misfolding or reducing its production. [1] While these approaches can improve outcomes, they are less effective at removing amyloid deposits that have already formed. This represents a significant unmet medical need.

The Discovery of PGG

Researchers screened over 1,500 plant extracts and found that extracts from pomegranate (Punica granatum) leaves and branches exhibited strong activity against pre-formed TTR fibrils. [3] Further investigation isolated PGG as the key component responsible for this effect. [3]

How PGG Works

In vitro experiments showed that PGG can disassemble amyloid fibrils formed from both mutant and wild-type TTR. [4] This is essential because ATTR can be hereditary, caused by gene mutations, or occur in older individuals with wild-type TTR. Notably, PGG selectively targeted TTR amyloid fibrils without affecting amyloid-β fibrils associated with Alzheimer’s disease, suggesting a degree of specificity. [1]

Promising Results in Animal and Human Models

Studies using Caenorhabditis elegans, a nematode expressing human TTR fragments, demonstrated that PGG reduced protein deposits, extended lifespan, and improved healthspan. [1] PGG successfully disrupted amyloid fibrils isolated from the cardiac tissue of a patient with hereditary ATTR. [1]

The Role of Galloyl Moieties

Structural analysis revealed that the galloyl groups present in PGG are essential for its amyloid-disrupting activity. [4] These chemical features appear to interact with the structure of amyloid fibrils, destabilizing them.

Future Directions

While these findings are preclinical, they highlight the therapeutic potential of plant-derived small molecules for treating ATTR amyloidosis. Further research is needed to confirm the safety and efficacy of PGG-based treatments in mammalian models and, eventually, in human clinical trials. [3] If successful, this could lead to a modern class of therapies that actively dismantle pathogenic amyloid aggregates, offering hope for patients with this debilitating condition.

Source: Glycosidic scaffold bearing multiple galloyl moieties from pomegranate (Punica granatum L.) disrupts transthyretin amyloid fibrils, iScience, November 21, 2025.