Excessive oxidative stress plays a critical role in the progression of various diseases. Recently, we showed that Terminalia bellirica (Gaertn.) Roxb. extract (TBE) inhibits inflammatory response and reactive oxygen species (ROS) production in THP‐1 macrophages. However, molecular mechanisms underlying anti‐inflammatory and antioxidant activities of TBE and its major polyphenolic compounds gallic acid (GA) and ellagic acid (EA) remain unclear. We found that TBE and GA attenuated LPS‐induced inflammatory mediator expression, ROS production, and activation of mitogen‐activated protein kinase (MAPK) and nuclear factor‐kappa B (NF‐κB) in RAW 264 macrophages. Furthermore, TBE and GA increased antioxidant enzyme expression along with upstream mediators nuclear factor erythroid‐2‐related factor 2 (Nrf2), Akt, and AMP‐activated protein kinase (AMPK). Importantly, knockdown of Nrf2 by siRNA and specific inhibition of Akt and AMPK significantly reduced antioxidant enzyme expression induced by TBE and GA. Finally, in vivo effects on histopathology and gene expression were assessed in tissues collected after intraperitoneal injection of LPS with or without TBE treatment. TBE enhanced antioxidant enzyme expression and improved acute kidney injury in LPS‐shock model mice. In conclusion, TBE and GA exert protective effects against inflammation and oxidative stress by suppressing MAPK/NF‐κB pathway and by activating Akt/AMPK/Nrf2 pathway. These results suggest that TBE and GA might be effective for the treatment of inflammation‐related diseases.

Nonalcoholic fatty liver disease (NAFLD) is one of the most common causes of chronic liver disease, sometimes ranges from simple steatosis to nonalcoholic steatohepatitis (NASH). Various hits including excessive hepatic steatosis, oxidative stress, apoptosis, and inflammation, contribute to NASH development. Gallic acid (GA), a natural polyphenol, was reported to exert a protective effect on hepatic steatosis in animal models, but the precise molecular mechanisms remain unclear. Here, we examined the effect of GA on hepatic lipid accumulation, apoptosis, and inflammatory response caused by hepatocyte–macrophage crosstalk. We demonstrated that GA attenuated palmitic acid (PA)-induced fat accumulation via the activation of AMP-activated protein kinase (AMPK) in HepG2 cells. GA also ameliorated cell viability and suppressed apoptosis-related gene expression and caspase 3/7 activity induced by PA and H₂O₂. In a co-culture of lipid-laden Hepa 1-6 hepatocytes and RAW 264 macrophages, GA reduced inflammatory mediator expression and induced antioxidant enzyme expression. These results indicate that GA suppresses hepatic lipid accumulation, apoptosis, and inflammation caused by the interaction between hepatocytes and macrophages. The potential effects of GA observed in our study could be effective in preventing NASH and its complications.

Inflammation in endothelial cells induces production of inflammatory cytokines and monocytes adhesion, which are crucial events in the initiation of atherosclerosis. Aronia berry (Aronia meranocalpa), also called black chokeberry, contains abundant anthocyanins that have received considerable interest for their possible relations to vascular health. The aim of this study was to investigate whether an anthocyanin-rich extract obtained from aronia berry can attenuate inflammatory responses in vascular endothelial cells. As a model of vascular endothelial inflammation, human umbilical vein endothelial cells (HUVECs) pretreated with aronia berry extract were stimulated with tumor necrosis factor-alpha (TNF-α). The expression levels of cytokines and adhesion molecules were analyzed. To investigate the effects of aronia berry extract on the adhesion of THP-1 monocytic cell, the static adhesion assay was carried out. The possible molecular mechanisms by which aronia berry extract regulated vascular inflammatory responses were explored. The mRNA expressions of interleukins (IL-1β, IL-6, and IL-8) and monocyte chemoattractant protein-1 (MCP-1) upregulated by TNF-α were significantly suppressed by pretreatment with aronia berry extract. Aronia berry extract decreased TNF-α-induced monocyte/endothelial adhesion and suppressed vascular cell adhesion molecule-1 (VCAM-1) expression, but did not affect intercellular adhesion molecule-1 (ICAM-1) expression. Moreover, aronia berry extract decreased the phosphorylation of signal transducer and activator of transcription 3 (STAT3) and the nuclear levels of STAT3 and interferon regulatory transcription factor-1 (IRF1). The nuclear translocation of nuclear factor-kappa B (NF-κB) was not inhibited by aronia berry extract. Aronia berry extract could exert anti-atherosclerotic effects on TNF-α-induced inflammation through inhibition of STAT3/IRF1 pathway in vascular endothelial cells.

The deciduous tree Terminalia bellirica found in Southeast Asia is extensively used in traditional Indian Ayurvedic medicine for the treatment of hypertension, rheumatism, and diabetes. The anti-atherogenic effect of Terminalia bellirica fruit has not been fully elucidated. Here, we investigated the effect of Terminalia bellirica extract (TBE) on low-density lipoprotein (LDL) oxidation and inflammation in macrophages. TBE showed 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity (EC₅₀: 7.2 ± 1.2 μg/mL) and 15-lipoxygenase inhibitory activity. TBE also significantly inhibited free radical-induced LDL oxidation compared to the solvent control in vitro. In THP-1 macrophages, TBE treatment resulted in significant decreases of the mRNA expression of tumor necrosis factor-alpha (TNF-α), interleukin-1beta (IL-1β), and lectin-like oxidized LDL receptor-1 (LOX-1). TBE also reduced matrix metalloproteinase (MMP)-9 secretion and intracellular reactive oxygen species (ROS) production in THP-1 macrophages. These results show that TBE has the inhibitory effects on LDL oxidation and macrophage inflammatory response in vitro, suggesting that its in vivo use might inhibit atherosclerosis plaque progression.

Polyphenol intake has been estimated in some populations; however, information about day-to-day and individual differences in polyphenol intake has not been well-evaluated. In this study, we aimed to examine within- and between-individual variation in polyphenol intake in Japanese male workers. First, 56 male subjects (aged 37.9±10.4 y) completed detailed 7-d dietary records (DR). We then calculated their total polyphenol intake using our polyphenol content database and the within- and between-individual variations. We also estimated the minimum number of days of dietary assessment required both to rank individuals within a group and to assess an individual’s usual polyphenol intake with acceptable accuracy. The estimated daily total polyphenol intake was 965±471 mg/d, which was largely sourced from beverages. The day-to-day variation (CV_w) for polyphenol intake was 43.6%, and the variation between the individuals in the population (CV_b) for polyphenol intake was 45.9%. A 4-d DR was required to rank individuals within a group with high correlation coefficients (r=0.9), and a 19-d DR was required to assess the individual’s usual polyphenol intake with 20% deviation. The CV_w for polyphenol intake was intermediate between those of the other nutrients, but the CV_b for polyphenol intake was largest among the nutrients. These results suggest that the dietary intake of polyphenols should be carefully estimated considering its within- and between-individual variation.