Punicalagin, a hydrolysable tannin of pomegranate juice, exhibits multiple biological effects, including inhibiting production of pro-inflammatory cytokines in macrophages. Autophagy, an intracellular self-digestion process, has been recently shown to regulate inflammatory responses. In this study, we investigated the anti-inflammatory potential of punicalagin in lipopolysaccharide (LPS) induced RAW264.7 macrophages and uncovered the underlying mechanisms. Punicalagin significantly attenuated, in a concentration-dependent manner, LPS-induced release of NO and decreased pro-inflammatory cytokines TNF-α and IL-6 release at the highest concentration. We found that punicalagin inhibited NF-κB and MAPK activation in LPS-induced RAW264.7 macrophages. Western blot analysis revealed that punicalagin pre-treatment enhanced LC3II, p62 expression, and decreased Beclin1 expression in LPS-induced macrophages. MDC assays were used to determine the autophagic process and the results worked in concert with Western blot analysis. In addition, our observations indicated that LPS-induced releases of NO, TNF-α, and IL-6 were attenuated by treatment with autophagy inhibitor chloroquine, suggesting that autophagy inhibition participated in anti-inflammatory effect. We also found that punicalagin downregulated FoxO3a expression, resulting in autophagy inhibition. Overall these results suggested that punicalagin played an important role in the attenuation of LPS-induced inflammatory responses in RAW264.7 macrophages and that the mechanisms involved downregulation of the FoxO3a/autophagy signaling pathway.

Diabetic nephropathy is a diabetic complication caused by chronic inflammation. As the primary polyphenol in pomegranate, punicalagin is believed to have significant anti-inflammatory properties. In this study, we established a mice model for diabetes induced by high-fat diet (HFD)/ streptozotocin (STZ) to verify the protective effect of punicalagin in vivo. The results show that the blood urea nitrogen (BUN), serum creatinine (CREA), and the urine albumin to creatinine ratio (UACR) were significantly decreased in diabetic mice after punicalagin intervention, and the symptoms of glomerular interstitial hyperplasia and glomerular hypertrophy were alleviated. Pyroptosis is an essential manner of programmed cell death in the inflammatory response; the expression of pyroptosis-related proteins such as interleukin-1 (IL-1β), cysteinyl aspartate-specific protease-1 (caspase-1), gasdermin D (GSDMD), and nucleotide-binding oligomerization domain, leucine-rich repeat and pyrin domain containing protein 3 (NLRP3) was decreased in our study, which proved that the administration of punicalagin for eight weeks can significantly inhibit pyroptosis in mice. In addition, punicalagin reduced high glucose-mediated protein expressions of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 4 (NOX4) and alleviated mitochondria damage. Low expression of NOX4 inhibits the dissociation of thioredoxin (Trx) and thioredoxin-interacting protein (TXNIP) and the suppression of NLRP3 inflammasome activation. To summarize, our study provided evidence that punicalagin can alleviate diabetic nephropathy, and the effect is associated with downregulating the expression of NOX4, inhibiting TXNIP/NLRP3 pathway-mediated pyroptosis, suggesting its therapeutic implications for complications of diabetes.

Obesity, a metabolic disease caused by excessive fat accumulation in the body, has attracted worldwide attention. Microcystin-LR (MC-LR) is a hepatotoxic cyanotoxin which has been reportedly to cause lipid metabolism disorder. In this study, C57BL/6J mice were fed a high-fat diet (HFD) for eight weeks to build obese an animal model, and subsequently, the obese mice were fed MC-LR for another eight weeks, and we aimed to determine how MC-LR exposure affects the liver lipid metabolism in high-fat-diet-induced obese mice. The results show that MC-LR increased the obese mice serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT), indicating damaged liver function. The lipid parameters include serum triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-c), and liver TG, which were all increased, whilst the high-density lipoprotein cholesterol (HDL-c) was decreased. Furthermore, after MC-LR treatment, histopathological observation revealed that the number of red lipid droplets increased, and that steatosis was more severe in the obese mice. In addition, the lipid synthesis-related genes were increased and the fatty acid β-oxidation-related genes were decreased in the obese mice after MC-LR exposure. Meanwhile, the protein expression levels of phosphorylation phosphatidylinositol 3-kinase (p-PI3K), phosphorylation protein kinase B (p-AKT), phosphorylation mammalian target of rapamycin (p-mTOR), and sterol regulatory element binding protein 1c (SREBP1-c) were increased; similarly, the p-PI3K/PI3K, p-AKT/AKT, p-mTOR/mTOR, and SREBP1/β-actin were significantly up-regulated in obese mice after being exposed to MC-LR, and the activated PI3K/AKT/mTOR/SREBP1 signaling pathway. In addition, MC-LR exposure reduced the activity of superoxide dismutase (SOD) and increased the level of malondialdehyde (MDA) in the obese mice’s serum. In summary, the MC-LR could aggravate the HFD-induced obese mice liver lipid metabolism disorder by activating the PI3K/AKT/mTOR/SREBP1 signaling pathway to hepatocytes, increasing the SREBP1-c-regulated key enzymes for lipid synthesis, and blocking fatty acid β-oxidation.

Background: The significant public health problem in Sub-Saharan Africa of household food insecurity is an underlying cause of malnutrition in Sub-Saharan Africa. This study aims to systematically study the association between household food insecurity, dietary diversity, and stunting. Methods: This review was carried out based on the recommendations of PRISMA (2015). We searched the literature in six bibliographic databases: PubMed, EMBASE, Science Direct, Web of Science, Google Scholar, and Scopus. The research was based on studies conducted in Sub-Saharan Africa about household food insecurity, dietary diversity, and stunting and was published between 2009 and 2020. Results: Out of 2398 original articles identified, only 21 articles met the specific requirements of this review. Two-thirds of the articles selected showed that stunting was linked to household food insecurity and dietary diversity. Conclusions: This study found that household food insecurity and dietary diversity are significantly associated with stunting in Sub-Saharan Africa. This review recommends that in order to yield a sustainable fight against childhood malnutrition in Sub-Saharan Africa, reliable guidelines and strategies are needed to address these factors related to malnutrition.

Ampelopsis grossedentata, also called vine tea, has been used as a traditional beverage in China for centuries. Vine tea contains rich polyphenols and shows benefit to human health, but the chemical and antioxidant properties of vine tea polyphenols from different locations remain unclear. This study aims to investigate the chemical and antioxidant properties of vine tea from three major production areas in China including Guizhou, Hunan, and Guangxi Provinces. The highest amount of polyphenol from vine tea was extracted by 70% ethanol at 70 °C for 40 min with ultrasonic treatment. The major compound in vine tea polyphenols (VTP) was determined as dihydromyricetin (DMY) by high-performance liquid chromatography (HPLC) and the content was estimated as 21.42%, 20.17%, and 16.47% of dry weight basis from Hunan, Guizhou, and Guangxi products, respectively. The antioxidant activities were investigated in vitro and in culture hepatic cells. VTP and DMY showed strong 1,1-Diphenyl-2-picrylhydrazyl free radical (DPPH) scavenging ability and high oxygen radical absorption capacity (ORAC) value in vitro. VTP and DMY also increased the level of nicotinamide adenine dinucleotide phosphate (NADPH):quinone oxidoreductase (NQO1) in HepG2 cells. Moreover, VTP and DMY enhanced the level of nuclear factor erythroid 2-related factor 2 (Nrf2) and reduced the level of Kelch-like ECH-associated protein 1 (Keap1). Taken together, our data demonstrated that the extraction of vine tea by 70% ethanol with ultrasonic treatment is a novel method to efficiently obtain components possessing stronger antioxidant activity. Furthermore, the results from the culture cells suggest that the bioactive component of vine tea might exert the antioxidant activity by activating the cellular Nrf2/Keap1 pathway.

Fisetin, a dietary flavonoid, is reported to have cellular antioxidant activity with an unclear mechanism. In this study, we investigated the effect of fisetin on the nuclear factor, erythroid 2-like 2 (Nrf2) signaling pathway in HepG2 cells to explore the cellular antioxidant mechanism. Fisetin upregulated the mRNA expression of heme oxygenase-1 (HO-1), glutamate-cysteine ligase catalytic subunit (GCLC), glutamate-cysteine ligase modifier subunit (GCLM), and NAD(P)H quinone oxidoreductase-1 (NQO1), and induced the protein of HO-1 but had no significant effect on the protein of GCLC, GCLM and NQO1. Moreover, nuclear accumulation of Nrf2 was clearly observed by immunofluorescence analysis and western blotting after fisetin treatment, and an enhanced luciferase activity of antioxidant response element (ARE)-regulated transactivation was obtained by dual-luciferase reporter gene assays. In addition, fisetin upregulated the protein level of Nrf2 and downregulated the protein level of Kelch-like ECH-associated protein 1 (Keap1). However, fisetin had no significant effect on Nrf2 mRNA expression. When protein synthesis was inhibited with cycloheximide (CHX), fisetin prolonged the half-life of Nrf2 from 15 min to 45 min. When blocking Nrf2 degradation with proteasome inhibitor MG132, ubiquitinated proteins were enhanced, and fisetin reduced ubiquitination of Nrf2. Taken together, fisetin translocated Nrf2 into the nucleus and upregulated the expression of downstream HO-1 gene by inhibiting the degradation of Nrf2 at the post-transcriptional level. These data provide the molecular mechanism to understand the cellular antioxidant activity of fisetin.