Quercetin for Kidney Disease? What a 2023 Commentary Really Says

The study “Commentary: Protective effect of quercetin on kidney diseases: from chemistry to herbal medicines” by Weiya Kong et al. (2023) analyzes and critiques the earlier review by Chen et al. on quercetin and kidney diseases. Kong and coauthors describe kidney disease as a life-threatening condition that often progresses from nephrotoxins, oxidative stress, or inflammation into fibrosis, chronic kidney disease (CKD), and eventually end-stage renal disease (ESRD). The commentary notes that Chen et al. gathered a wide range of data on quercetin’s pharmacokinetics, its presence in herbal medicines, and its reported protective roles in nephrotoxicity, acute and chronic kidney injury, diabetic nephropathy (DN), renal aging, and rare kidney conditions. At the same time, Kong et al. argue that the review is “systematic and detailed” but also fragmented, overly positive, and not cautious enough about safety and the lack of human data. This blog simply paraphrases and quotes that commentary, without adding new scientific claims.

Kidney disease can be driven by nephrotoxins, oxidative stress, and inflammation, and these insults can push the kidney toward fibrosis, CKD, and ESRD. Treatment options for kidney injury are still limited, which makes any potential kidney-supporting compound, like quercetin, very interesting in research settings. Quercetin is a natural flavonoid with reported antioxidant, antihypertensive, and antidiabetic effects. Prior work has suggested that quercetin has been studied in the context of cancer, cardiovascular disease, and metabolic disorders.

The original review by Chen et al. tried to gather what is known about quercetin across many kidney disease models. Kong et al. acknowledge that “this is a systematic and detailed review aimed at showcasing the potential value of quercetin in the treatment of kidney disease.” However, the commentary also warns that the story is not complete. It raises questions about how well the review explains mechanisms, how balanced the evidence is, and whether the conclusions about clinical potential go too far based on mostly animal and cell data.

This scientific paper is a commentary, not a new clinical trial or animal experiment. Kong et al. did not run new lab studies. Instead, the authors:

• Read and evaluated the 2022 quercetin kidney review by Chen et al.
• Compared its claims and structure with other recent research on quercetin and kidney disease.
• Identified gaps in mechanisms, study selection, and clinical interpretation.
• Wrote a structured critique that discusses limitations under clear headings, such as “Limitations” and “Discussion.”

Because this is a commentary, the “methodology” is mainly critical reading and scientific argument, rather than in vivo or in vitro experimentation. All points in this blog come directly from how Kong et al. describe, quote, and assess the earlier quercetin review.

Kong et al. start by recognizing the strengths of Chen et al.’s work. They describe the earlier review as “comprehensive” and note that it covers many aspects, from quercetin’s chemistry and bioavailability to its reported roles in nephrotoxicity, acute and chronic injury, DN, renal aging, and rare kidney diseases. The commentary agrees that quercetin has antioxidant, antihypertensive, and antidiabetic activities and that the original review did a good job of summarizing a broad range of experimental studies.

Overall, the commentary sees the original review as presenting a “highly promising treatment concept” and suggests that the idea of quercetin for kidney protection in research settings is worth further exploration, as long as important gaps are addressed.

The commentary states that “the most significant flaw of this study is that it summarizes multiple academic research results in a fragmented way.” According to Kong et al., the review lists many results but does not connect them into a clear, unified argument.

One example is the discussion of how quercetin’s chemical structure relates to its biological activity. The commentary notes that this relationship is “not explained clearly and systematically enough.” Another example is renal fibrosis. Chen et al. focused heavily on transforming growth factor beta (TGF β) inhibition, but the commentary argues that other fibrosis-related pathways and factors are not explored in depth. The authors ask important questions, such as “Do these factors interact with quercetin?” but point out that the review does not provide clear answers.

Kong et al. also believe that relevant studies and pathways were left out. In the section on DN, the commentary suggests that the review could have added:

• More detail on glucose transporter 4 (GluT4) and AMP-activated protein kinase (AMPK) signaling, and extracellular signal-regulated kinase (ERK) related mechanisms, for the hypoglycemic effects of quercetin.
• Discussion of the peroxisome pathway and nuclear factor erythroid 2-related factor 2 (Nrf2), and how these antioxidant pathways interact with quercetin in DN.
• A more systematic look at autophagy-related markers, such as LC3 and other autophagy proteins.

The commentary notes that the review rarely analyzes or compares different research results and opinions. Without this kind of comparison, it is hard to reach a “more balanced and thorough conclusion.”

One of the strongest points in the commentary is that the original review “downplays the fact that quercetin cannot yet be used for the clinical prevention and treatment of kidney disease.” Kong et al. see this as a potential risk for clinical decision-making.

They raise three main concerns:

1. The review is “too biased towards affirming the efficacy of quercetin,” without fully discussing toxicology, safe dosage ranges, or possible adverse reactions. Even if quercetin looks promising, “reliable pharmaceutical pathways are yet to be found,” so safety and efficiency in humans are not established.
2. Most evidence comes from animal experiments. The commentary states that “the judgment on human applicability is still inadequate” and calls current conclusions “too hasty.” Appropriate clinical studies are still missing.
3. The review does not provide clear medication indications or differentiated treatment strategies. There is little analysis of how different races, disease types, and disease stages might change quercetin’s effects. This lack of detail “largely limits its practical application.”

Most importantly, researchers and clinicians need more toxicology data, safe dosage ranges, and well-designed human clinical trials before quercetin can be considered for use in kidney prevention or treatment.

Kong et al. do not dismiss quercetin as a dead end. Instead, the commentary treats quercetin as a promising idea that needs much more work before any standard use in kidney disease could be considered. The authors write that, although the review presents a “highly promising treatment concept,” several “significant obstacles” must be overcome before quercetin can be recommended as a standard treatment.

The key implications from this commentary include:

• New reviews should organize evidence more clearly and link mechanisms such as TGF β, peroxisome pathways, Nrf2, AMPK, and autophagy-related proteins like LC3 into a coherent mechanistic model.
• Future work should include more diverse and up-to-date studies, especially on signaling pathways and cross-talk in diabetic nephropathy, fibrosis, and oxidative stress.
• Most importantly, researchers and clinicians need more toxicology data, safe dosage ranges, and well-designed human clinical trials before quercetin can be considered for use in kidney prevention or treatment.

Kong et al. end by hoping that “further research and rigorous testing can overcome its shortcomings and make the conclusion more reliable and cautious.”

This 2023 scientific commentary sends a clear message about quercetin and kidney disease. Quercetin remains an interesting natural compound with antioxidant and metabolic effects, and the original review by Chen et al. did valuable work by collecting many preclinical studies across nephrotoxicity, acute and chronic kidney injury, diabetic nephropathy (DN), and renal aging. At the same time, Kong et al. highlight that the evidence is fragmented, mechanisms are not fully integrated, and clinical readiness is easily overstated.

According to this commentary, quercetin cannot yet be considered suitable for routine clinical prevention or treatment of kidney disease. More detailed mechanistic work, broader study selection, careful safety analysis, and robust human trials are needed before strong clinical claims can be made. This blog simply summarizes and paraphrases the commentary by Kong et al., with the goal of making its cautious, balanced message easier to understand.