Black Raspberry Extract Prevents Kidney Scarring by Blocking Signals

Greg Howard
14th May, 2025

Black Raspberry Extract Prevents Kidney Scarring by Blocking Signals

Among nine natural product extracts visualized as powders (a) and solutions (c), Rubus coreanus (MN705) was selected as the potential anti-fibrotic agent because it exhibited the most favorable cell viability profile in cytotoxicity assays (b).

Image adapted from: Jin et al. / CC BY (Source)

Key Findings

  • Researchers at Seoul National University found that a natural berry extract from Rubus coreanus can reduce kidney scarring in mice
  • The extract lowered harmful protein buildup and increased protective enzymes in kidney cells
  • These findings suggest Rubus coreanus could be a promising new treatment to slow chronic kidney disease
Kidney fibrosis is a critical factor in the progression of chronic kidney disease (CKD), a condition that affects a significant portion of the global population, particularly adults over the age of 70[2]. This scarring process impairs the kidney's ability to function properly, leading to severe health complications. Despite its prevalence, effective treatments to halt or reverse kidney fibrosis remain elusive, making it a major focus of ongoing medical research. Recent studies have shed light on the cellular and molecular mechanisms driving kidney fibrosis, identifying various pathways and cell types that contribute to the disease's progression[2]. Among these, interstitial myofibroblasts play a pivotal role by producing excessive extracellular matrix proteins, which accumulate and cause scarring. Additionally, inflammatory signals released by damaged epithelial cells further exacerbate fibrosis, creating a vicious cycle that undermines kidney function. In the search for novel therapeutic approaches, traditional Chinese herbal medicine has emerged as a promising avenue. Chinese herbal remedies have a long history of use and offer a diverse array of compounds that may target different aspects of kidney fibrosis[3]. Researchers have been particularly interested in these natural compounds for their potential to modulate specific pathological mechanisms involved in fibrosis, such as inflammation and oxidative stress. Building on this foundation, a recent study conducted by researchers at Seoul National University Boramae Medical Center[1] explored the efficacy of a water-soluble extract from Rubus coreanus, a berry known for its anti-oxidative properties, in preventing kidney fibrosis. The study employed both in vivo and in vitro models to assess the extract's potential benefits. In the animal component of the study, male C57BL/6 mice underwent a procedure called unilateral ureteral obstruction (UUO), which induces kidney fibrosis by blocking urine flow and causing injury to the kidney. The mice were divided into groups receiving either a vehicle (distilled water) or varying doses of the Rubus coreanus extract (MN705). After a week of treatment, the researchers performed the UUO operation and continued the extract administration for another week. The results were promising: mice treated with MN705 showed significantly reduced areas of kidney interstitial fibrosis compared to those that received the vehicle. Specifically, the fibrosis area decreased from an average of 17.2% to 10.6% in the treatment group. To understand the molecular underpinnings of these effects, the researchers conducted western blot analyses, a technique used to detect specific proteins in tissue samples. They focused on α-Smooth Muscle Actin (α-SMA), a marker of myofibroblast activation. Elevated levels of α-SMA are associated with increased fibrosis. The study found that MN705 treatment significantly lowered α-SMA protein levels, indicating a reduction in myofibroblast activity and, consequently, fibrosis. Complementing the animal studies, the researchers also performed in vitro experiments using HK-2 cells, a type of human renal proximal tubular epithelial cell. These cells were exposed to transforming growth factor-beta (TGF-β), a cytokine that promotes fibrosis by activating several signaling pathways, including the Smad pathway. When treated with MN705, the HK-2 cells exhibited a dose-dependent decrease in fibronectin and phosphorylated Smad2/3 proteins, both of which are involved in the fibrotic process. Additionally, there was an increase in manganese superoxide dismutase (MnSOD), an enzyme that protects cells from oxidative damage. These findings suggest that Rubus coreanus extract mitigates kidney fibrosis by interfering with TGF-β-related signaling pathways, specifically the Smad and Smurf pathways, which are crucial in the development of fibrosis. By inhibiting these pathways, MN705 prevents the activation of myofibroblasts and reduces the production of extracellular matrix proteins that lead to scarring. The study by Seoul National University Boramae Medical Center not only corroborates previous research highlighting the importance of targeting specific cellular pathways to combat kidney fibrosis[2] but also adds to the growing body of evidence supporting the use of Chinese herbal medicines in treating this condition[3]. By demonstrating the effectiveness of Rubus coreanus extract in both animal and cell models, the research provides a promising foundation for developing new treatments aimed at preventing or slowing the progression of kidney fibrosis. Future research may focus on clinical trials to evaluate the safety and efficacy of Rubus coreanus extract in humans with CKD. Additionally, further investigations could explore the specific compounds within the extract responsible for its anti-fibrotic effects, potentially leading to the development of targeted therapies. This study highlights the potential of integrating traditional herbal medicine with modern biomedical approaches to address complex health challenges like kidney fibrosis.

MedicineHealthBiochem

References

Main Study

1) Rubus coreanus extract prevents kidney fibrosis through TGF-β/Smad pathway inhibition

Published 12th May, 2025

https://doi.org/10.1371/journal.pone.0321282

Related Studies

3) Research Progress of Chinese Herbal Medicine Intervention in Renal Interstitial Fibrosis.

https://doi.org/10.3389/fphar.2022.900491


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