Curcumin alleviates hepatic steatosis by targeting a microbiota-KYN-AHR-H3K27ac-Cebpb epigenetic axis, demonstrating that its therapeutic effects in MASLD are gut microbiota-dependent.
A meta-analysis of seven clinical studies found that curcumin supplementation reduced serum aminotransferase levels in patients, supporting its potential clinical benefit for MASLD.
Curcumin reduced hepatic lipid accumulation and metabolic dysfunction in high-fat diet-fed rats, but these effects were markedly weakened in antibiotic-induced pseudo-germ-free rats.
Fecal microbiota transplantation (FMT) from curcumin-treated donors transferred metabolic and histological benefits to antibiotic-conditioned recipient rats.
Fecal 16S rRNA sequencing identified Clostridium_sensu_stricto_1 as a curcumin-suppressed, pro-steatotic taxon whose reconstitution abolished curcumin-mediated hepatic protection.
Untargeted hepatic metabolomics and LC-MS identified kynurenine (KYN) as a C. sensu-derived metabolite that accumulates in the liver, and curcumin reduced hepatic KYN levels.
Integrated multi-omic analyses identified hepatocyte-enriched CEBPB as a key epigenetically regulated effector in MASLD pathogenesis.
KYN activated the aryl hydrocarbon receptor (AHR), increased H3K27ac enrichment at the Cebpb locus, and induced Cebpb transcription, as demonstrated by luciferase reporter assays and ChIP-qPCR.
CEBPB knockdown blocked KYN-induced PI3K-AKT pathway activation and lipid accumulation, linking the epigenetic mechanism to downstream lipogenic signaling.
In vivo KYN supplementation largely reversed curcumin-mediated hepatic protection, confirming KYN's causal role in the pathway.
This research suggests that curcumin, the active compound found in turmeric, can reduce fat buildup in the liver — a condition known as metabolic dysfunction-associated steatotic liver disease (MASLD) — but it does so primarily by changing the bacteria living in the gut rather than by acting directly on the liver. In rats fed a high-fat diet, curcumin reduced liver fat and improved metabolic health. However, when the gut bacteria were wiped out with antibiotics, most of curcumin's benefits disappeared. The researchers traced this effect to a specific gut bacterium called Clostridium_sensu_stricto_1, which curcumin suppresses. When this bacterium was artificially reintroduced, curcumin stopped working, confirming that suppressing this microbe is central to curcumin's effectiveness. The research further uncovered how this gut bacterium harms the liver at a molecular level. Clostridium_sensu_stricto_1 produces a molecule called kynurenine (KYN), which travels to the liver and activates a receptor called AHR. This triggers chemical changes to DNA packaging (specifically, increased H3K27ac marks at a gene called Cebpb), causing a liver protein called CEBPB to be overproduced. CEBPB then switches on fat-accumulation pathways (via PI3K-AKT signaling), leading to liver steatosis. Curcumin breaks this chain by reducing the abundance of the KYN-producing bacterium, thereby lowering KYN levels and preventing the downstream epigenetic and metabolic harm. This research matters because it identifies a specific, step-by-step molecular pathway — gut microbiota → kynurenine → AHR → epigenetic change → CEBPB → liver fat — that could be targeted therapeutically. A meta-analysis of seven human clinical trials included in this study also showed that curcumin lowered liver enzyme levels in people, suggesting the findings have potential human relevance. The work positions both curcumin supplementation and reduction of kynurenine levels as potential strategies for addressing a liver condition that currently has very few effective treatments.
Zhu Y, Ma J, Wang D, Cui M, Peng J, Lu X, et al.. (2026). Curcumin alleviates metabolic dysfunction-associated steatotic liver disease via gut microbiota-dependent epigenetic alterations.. Molecular biomedicine. https://doi.org/10.1186/s43556-026-00606-1