Benzitripyrranes were prepared by reacting diphenyl-substituted benzenedicarbinols with excess pyrrole in the presence of BF3·Et2O. These dipyrrolic compounds underwent acid-catalyzed condensations with a pyrrole dialdehyde to afford good yields of diphenylbenziporphyrins, and further reaction with palladium(II) acetate gave stable organometallic derivatives. The X-ray crystal structure of a palladium(II) benziporphyrin showed that the system deviates significantly from planarity. Although the benzitripyrranes failed to give stable macrocyclic products with furan or thiophene dialdehydes, they afforded tetraphenyl heterobenziporphyrins upon reaction with diphenyl-substituted furan- or thiophenedicarbinols and BF3·Et2O. Benziporphyrins and their heteroanalogues showed no indication of a diamagnetic ring current by proton NMR spectroscopy, but addition of TFA gave rise to the formation of weakly diatropic dications.

Objective Urolithin A (UroA) is a major metabolite of ellagic acid produced following microbial catabolism in the gut. Emerging evidence has suggested that UroA modulates energy metabolism in various cells. However, UroA’s physiological functions related to obesity and insulin resistance remain unclear. Methods Male mice were intraperitoneally administrated either UroA or dimethyl sulfoxide (vehicle) along with a high‐fat diet for 12 weeks. Insulin sensitivity was evaluated via glucose and insulin tolerance tests and acute insulin signaling. The effects of UroA on hepatic triglyceride accumulation, adipocyte size, mitochondrial DNA content, and proinflammatory gene expressions were determined. The impact of UroA on macrophage polarization and mitochondrial respiration were assessed in bone marrow–derived macrophages. Results Administration of UroA (1) improved systemic insulin sensitivity, (2) attenuated triglyceride accumulation and elevated mitochondrial biogenesis in the liver, (3) reduced adipocyte hypertrophy and macrophage infiltration into the adipose tissue, and (4) altered M1/M2 polarization in peritoneal macrophages. In addition, UroA favored macrophage M2 polarization and mitochondrial respiration in bone marrow‐derived macrophages. Conclusions UroA plays a direct role in improving systemic insulin sensitivity independent of its parental compounds. This work supports UroA’s role in the metabolic benefits of ellagic acid–rich foods and highlights the significance of its microbial transformation in the gut.

Brown adipose tissue (BAT) is a crucial regulator of energy expenditure. Emerging evidence suggests that n-3 PUFA potentiate brown adipogenesis in vitro. Since the pregnancy and lactation is a critical time for brown fat formation, we hypothesized that maternal supplementation of n-3 PUFA promotes BAT development in offspring. Female C57BL/6 mice were fed a diet containing n-3 PUFA (3%) derived from fish oil (FO), or an isocaloric diet devoid of n-3 PUFA (Cont) during pregnancy and lactation. Maternal n-3 PUFA intake was delivered to the BAT of neonates significantly reducing the n-6/n-3 ratio. The maternal n-3 PUFA exposure was linked with upregulated brown-specific gene and protein profiles and the functional cluster of brown-specific miRNAs. In addition, maternal n-3 PUFA induced histone modifications in the BAT evidenced by 1) increased epigenetic signature of brown adipogenesis, i.e., H3K27Ac and H3K9me2, 2) modified chromatin-remodeling enzymes, and 3) enriched the H3K27Ac in the promoter region of Ucp1. The offspring received maternal n-3 PUFA nutrition exhibited a significant increase in whole-body energy expenditure and better maintenance of core body temperature against acute cold treatment. Collectively, our results suggest that maternal n-3 PUFA supplementation potentiates fetal BAT development via the synergistic action of miRNA production and histone modifications, which may confer long-lasting metabolic benefits to offspring.

Urolithin A (UroA) is a gut metabolite produced from ellagic acid-containing foods such as pomegranates, berries, and walnuts. UroA is of growing interest due to its therapeutic potential for various metabolic diseases based on immunomodulatory properties. Recent advances in UroA research suggest that UroA administration attenuates inflammation in various tissues, including the brain, adipose, heart, and liver tissues, leading to the potential delay or prevention of the onset of Alzheimer’s disease, type 2 diabetes mellitus, and non-alcoholic fatty liver disease. In this review, we focus on recent updates of the anti-inflammatory function of UroA and summarize the potential mechanisms by which UroA may help attenuate the onset of diseases in a tissue-specific manner. Therefore, this review aims to shed new insights into UroA as a potent anti-inflammatory molecule to prevent immunometabolic diseases, either by dietary intervention with ellagic acid-rich food or by UroA administration as a new pharmaceutical drug.

Whole red raspberry polyphenols (RRW), including ellagic acid, and their gut-derived metabolite, urolithin A (UroA), attenuate inflammation and confer health benefits. Although results from recent studies indicate that polyphenols and UroA also provide neuroprotective effects, these compounds differ in their bioavailability and may, therefore, have unique effects on limiting neuroinflammation. Accordingly, we aimed to compare the neuroprotective effects of RRW and UroA on BV-2 microglia under both 3 h and 12 and 24 h inflammatory conditions. In inflammation induced by lipopolysaccharide (LPS) and ATP stimulation after 3 h, RRW and UroA suppressed pro-inflammatory cytokine gene expression and regulated the JNK/c-Jun signaling pathway. UroA also reduced inducible nitric oxide synthase gene expression and promoted M2 microglial polarization. During inflammatory conditions induced by either 12 or 24 h stimulation with LPS, UroA—but not RRW—dampened pro-inflammatory cytokine gene expression and suppressed JNK/c-Jun signaling. Taken together, these results demonstrate that RRW and its gut-derived metabolite UroA differentially regulate neuroprotective responses in microglia during 3 h versus 12 and 24 h inflammatory conditions.