Two papers, starting with a 2022 abstract of an ongoing in vitro study with rodent cells:
“Exercise mimetics may target and activate the same mechanisms that are upregulated with exercise administration alone. This is particularly useful under conditions where contractile activity is compromised due to muscle disuse, disease, or aging.
Sulforaphane and Urolithin A represent our preliminary candidates for antioxidation and mitophagy, respectively, for maintaining mitochondrial turnover and homeostasis. Preliminary results suggest that these agents may be suitable candidates as exercise mimetics, and set the stage for an examination of synergistic effects.”
https://faseb.onlinelibrary.wiley.com/doi/10.1096/fasebj.2022.36.S1.R3745 “Exercise mimicry: Characterization of nutraceutical agents that may contribute to mitochondrial homeostasis in skeletal muscle” (study not available)
A second 2022 paper reviewed what’s known todate regarding urolithins:
“Urolithins (Uros) are metabolites produced by gut microbiota from the polyphenols ellagitannins (ETs) and ellagic acid (EA). ETs are one of the main groups of hydrolyzable tannins. They can occur in different plant foods, including pomegranates, berries (strawberries, raspberries, blackberries, etc.), walnuts, many tropical fruits, medicinal plants, and herbal teas, including green and black teas.
Bioavailability of ETs and EA is very low. Absorption of these metabolites could be increased by co-ingestion with dietary fructooligosaccharides (FOS).
Effects of other experimental factors: post-intake time, duration of administration, diet type (standard and high-fat), and ET dosage (without, low, and high ET intake) in ETs metabolism were evaluated in blood serum and urine of rats consuming strawberry phenolics. Highest concentrations were obtained after 2–4 days of administration.
Various crucial issues need further research despite significant evolution of urolithin research. Overall, whether in vivo biological activity endorsed to Uros is due to each specific metabolite and(or) physiological circulating mixture of metabolites and(or) gut microbial ecology associated with their production is still poorly understood.
- Ability of Uros to cross the blood-brain barrier and the nature of metabolites and concentrations reached in brain tissues need to be clarified.
- Specific in vivo activity for each free and conjugated Uro metabolite is unknown. Studies on different Uro metabolites and their phase-II conjugates are needed to understand their role in human health.
- Evidence on safety and impact of Uros on human health is still scarce and only partially available for Uro-A.
- It is unknown whether there are potential common links between gut microbial ecologies of the two unambiguously described metabotypes so far, i.e., equol (isoflavones) and Uros (ellagitannins).
- Gut microbes responsible for producing different Uros still need to be better identified and characterized, and biochemical pathways and enzymes involved.”
https://onlinelibrary.wiley.com/doi/10.1002/mnfr.202101019 “Urolithins: a Comprehensive Update on their Metabolism, Bioactivity, and Associated Gut Microbiota”