Exploration of natural flavones' bioactivity and bioavailability in chronic inflammation induced-type-2 diabetes mellitus.

Diabetes, being the most widespread illness, poses a serious threat to global public health. It seems that inflammation plays a critical role in the pathophysiology of diabetes. This review aims to demonstrate a probable link between type 2 diabetes mellitus (T2DM) and chronic inflammation during its development. Additionally, the current review examined the bioactivity of natural flavones and the possible molecular mechanisms by which they influence diabetes and inflammation. While natural flavones possess remarkable anti-diabetic and anti-inflammatory bioactivities, their therapeutic use is limited by the low oral bioavailability. Several factors contribute to the low bioavailability, including poor water solubility, food interaction, and unsatisfied metabolic behaviors, while the diseases (diabetes, inflammation, etc.) causing even less bioavailability. Throughout the years, different strategies have been developed to boost flavones' bioavailability, including structural alteration, biological transformation, and innovative drug delivery system design. This review addresses current advancements in improving the bioavailability of flavonoids in general, and flavones in particular. Clinical trials were also analyzed to provide insight into the potential application of flavonoids in diabetes and inflammatory therapies.

4-Methoxydalbergione is a potent inhibitor of human astroglioma U87 cells in vitro and in vivo.

Astroglioma is the most common primary tumor in the central nervous system without effective treatment strategies. Temozolomide (TMZ) is a chemotherapeutic drug to treat astroglioma but exhibits low potency and has side effects. Therefore, there is an urgent need to develop new compounds to treat astroglioma. Dalbergia sissoo Roxb was the source of Dalbergia odorifera in traditional Chinese medicine (TCM) and has been clinically used as an anti-tumor medicine. 4-Methoxydalbergione (4MOD) is purified from Dalbergia sissoo Roxb., and shows an inhibitory effect on osteosarcoma, but its effects on astroglioma have not been reported. Here, we evaluate its anti-astroglioma effects on both in vitro and in vivo models. In cultured astroglioma U87 cells, 4MOD inhibited cell proliferation and induced cell apoptosis in a time- and concentration-dependent manner. Compared with TMZ, 4MOD exhibited a tenfold greater potency of anti-astroglioma effects. 4MOD effectively stalled the cell cycle in G2 phase. Transcriptome sequencing (RNA-seq) showed that 4MOD upregulated 158 genes and downregulated 204 genes that are mainly enriched in cell membrane, cell division, cell cycle, p53, TNF, and MAPK signaling pathways, which may underlie its anti-tumor mechanisms. In a nude mouse xenograft model transplanted with U87 cells, 10 mg/kg 4MOD slowed down tumor growth rate, while at 30 mg/kg dose, it reduced tumor size. Collectively, this study demonstrates that 4MOD is a potent native compound that remarkably inhibits U87 astroglioma growth in both in vitro and in vivo models.

Treponema primitia α1-2-fucosyltransferase-catalyzed one-pot multienzyme synthesis of fucosylated oligosaccharide lacto-N-fucopentaose I with antiviral activity against enterovirus 71.

Fucosylated oligosaccharides have important biological functions as well as an excellent antiviral activity. A novel α 1-2-fucosyltransferase (α 2FT) from Treponema primitia (Tp2FT) was cloned and expressed in Escherichia coli BL21(DE3) and purified as an N-His6-tagged fusion protein (His6-Tp2FT). Mass spectrometry was carried out to identify the products of enzymatic reaction. The Tp2FT exhibited strict acceptor substrate specificity for type 1 structure (Galß1-3GlcNAc)-containing glycans. It might be a promising emzyme for the chemo-enzymatic synthesis of lacto-N-fucopentaose I (LNFP I), which is one of the important fucosylated oligosaccharides. In this study, different in vitro experiments were used to study the biological activities of LNFP I. It could reduce the concentrations of inflammatory cytokines and effectively inhibit the synthesis of enterovirus 71 proliferation. LNFP I was an inhibitor of enterovirus 71 in the early stages of infection, it can used in infant nutrition and might provide a new drug for hand foot mouth disease.

Anti-inflammatory activity of flavonols via inhibiting MAPK and NF-κB signaling pathways in RAW264.7 macrophages.

Fisetin (Fis), quercetin (Que), and myricetin (Myr) are flavonols with similar structure but different number of hydroxyl groups. The present research focused on the anti-inflammatory effect of these three flavonols in lipopolysaccharide-stimulated RAW264.7 cells. The number and site of hydroxyl group in flavonols obviously affected their anti-inflammation activity. These flavonols suppressed the overproduction of nitric oxide. Fis showed the best activity with an inhibition rate of 52% at 20 µM. Moreover, the flavonols reduced the levels of ROS, TNF-α, and IL-6. The mechanistic study showed that they inhibited the activation of NF-κB and MAPK pathways by suppressing the phosphorylation of IκBα, p65, JNK, ERK, p38, MEK, and reducing the nuclear translocation of NF-κB p65. In addition, the metabolism of the flavonols was examined. The results indicated that Fis was both methylated and glucuronidated. Que and Myr were mainly transformed into methylated products. This study highlights the anti-inflammatory activity of flavonols, particularly Fis, which has the potential for the prevention or treatment of inflammation as an adjuvant medicine or food additive.

Chemoenzymatic synthesis of fucosylated oligosaccharides using Thermosynechococcus α1-2-fucosyltransferase and their application in the regulation of intestinal microbiota.

A novel bacterial α 1-2-fucosyltransferase (α 2FT) from Thermosynechococcus sp. NK55a (Ts2FT) has been discovered and characterized. It shares 28-62% protein sequence homology to α 2FTs reported previously. The Ts2FT was cloned as an N-terminal His6-tagged recombinant protein (His6-Ts2FT) and expressed in E. coli BL21 (DE3). It was expressed at a level of 6.2 mg/L culture after induction with 0.05 mM of isopropylß-d-1-thiogalactoside (IPTG) at 16 °C for 20 h. It showed the optimal activity at a reaction temperature of 40 °C and pH of 7.0. The presence of a Mg2+ improved its catalytic efficiency. Ts2FT displayed a strict acceptor specificity and could recognize only ß1-3-galatoside acceptors. It was used efficiently for one-pot multienzyme synthesis of fucosylated oligosaccharides. One of the products, lacto-N-fucopentaose I was shown to promote the growth of intestinal probiotics including those belonging to Acidobacteria, Actinobacteria, Proteobacteria, Planctomycetes, and Chloroflexi.

Ser-Leu substitution at P2 position of the hemagglutinin cleavage site attenuates replication and pathogenicity of Eurasian avian-like H1N2 swine influenza viruses.

Swine influenza viruses not only constitute a potential economic problem for livestock, but also pose a substantial threat to human health. Mutation in the proteolytic cleavage site of hemagglutinin (HA) is recognized as an essential factor of tissue tropism and viral pathogenicity. However, the molecular properties of the cleavage site of Eurasian avian-like swine (EA) H1N2 virus remain largely unknown. In this study, we found a serine-leucine (Ser-Leu) substitution at the P2 position of the HA cleavage site (S328 L) in naturally occurring EA H1N2 virus. To study the effect of this substitution, we used reverse genetics to generate recombinant wild-type and mutant viruses containing a single amino acid mutation at the P2 position in A/swine/Guangdong/YJ28/2014 (YJ28) or A/swine/Guangdong/DG2/2015 (DG2) background. In vitro experiments showed that the Ser-Leu substitution at the P2 position attenuated the viral replication and HA cleavage efficiency. In vivo analyses revealed that, while all mice inoculated with r/DG2-S328 L or r/YJ28 viruses survived, the survival rates of r/DG2- and r/YJ28-L328S-inoculated animals were 20 % and 40 %, respectively. Furthermore, the Ser-Leu substitution at the P2 position attenuated the replication in nasal turbinate and lungs. In summary, this amino acid change may be useful to understand the molecular properties of the cleavage site and be valuable for vaccine development.

Physicochemical characterization of a polysaccharide from Agrocybe aegirita and its anti-ageing activity.

The aim of the present study is to characterize the structure of a novel natural polysaccharide from Agrocybe aegirita (AAPS) and evaluate its anti-aging activity. The MALLS and GC-MS analysis indicated that the AAPS with molecular weights of 1.81 × 104 Da was mainly composed by rhamnose, fucose, mannose, and glucose in a molar ratio of 2.90:10.25:3.70:38.27. The FT-IR and NMR analysis showed that the backbone of AAPS was α-L-Rhap-(1→6)-ß-D-Glcp-(1→2)-α-L-Fucp-(1→6)-α-D-Glcp-(1→5)-α-L-Araf-(1→4)-ß-D-GlcpA-(1→5)-α-L-Araf-(1→6)-α-D-Manp-(1→6)-α-D-Manp-(1→2)-α-L-Fucp-(1→6)-ß-D-Glap-(1→2)-α-L-Rhap-(1→6)-ß-D-Galp-(1→, which linked with two side chains α-L-Fucp-(1→6)-ß-D-Glcp-(1→6)-ß-D-Manp-(1→ and α-D-Xylp-(1→2)-α-L-Fucp-(1→5) -α-D-Araf-(1→6)-ß-D-Galp-(1→ at OH2 at H-4-arabinose and the terminal Galp residues, respectively. The MRC-5 cells induced by H2O2 were used to explore the anti-ageing effect and its underlying mechanism of AAPS. It showed a potent anti-ageing activity, representing by the increased cell viability and ß-Gal viability, prevented G1-phase cell-cycle arrest, and decreased mitochondrial membrane potential. The polysaccharides extracted from A. aegirita might be applied in functional food as anti-ageing ingredient.

Regulatory effect of Grifola frondosa extract rich in polysaccharides and organic acids on glycolipid metabolism and gut microbiota in rats.

The present study investigated the composition of water extract of Grifola frondosa (GFWE) and its regulatory effects on glycolipid metabolism and gut microbiota in rats. Structural characteristics of GFWE were detected by high performance liquid chromatography and ultra-high-performance liquid chromatography with mass spectrometry. The hypoglycemic and hypolipidemic activities of GFWE were obtained by inhibition of weight gain, recovery of serum glucose and lipid, and reverse of liver tissue damage. GFWE has up-regulated the relative mRNA and protein expression levels of adenine monophosphate activated protein kinase-α, peroxisome proliferator-activated receptors-α, and glucokinase, while down-regulated sterol regulatory element-binding transcription factor-1c and acetyl CoA carboxylase. Moreover, GFWE increased the abundances of caecal bacteria Oscillibacter and Barnesiella, which showed a significant negative correlation with serum glucose and lipid parameters. And GFWE enhanced the levels of total bile acids and short-chain fatty acids in the cecum. These results indicated that GFWE could be provided as a potential candidate to regulate glycolipid metabolism and gut microbiota.

Evidence of H10N8 influenza virus infection among swine in southern China and its infectivity and transmissibility in swine.

Infection with a novel H10N8 influenza virus in humans was first described in China in December 2013, which raised concerns related to public health. This novel virus was subsequently confirmed to have originated from a live poultry market. However, whether this virus can infect other mammals remains unclear. In the present study, antibody specific for H10N8 influenza virus was detected in swine herds in southern China during serological monitoring for swine influenza virus. The pathogenicity and transmissibility of this H10N8 influenza virus to swine was examined. The results showed that swine are susceptible to infection with human-origin H10N8 influenza virus, which causes viral shedding, severe tissue lesions, and seroconversion, while infection with avian-origin H10N8 influenza virus causes only seroconversion and no viral shedding. Importantly, human-origin H10N8 influenza virus can inefficiently be transmitted between swine and cause seroconversion through direct contact. This study provides a new perspective regarding the ecology of H10N8 influenza virus and highlights the importance of epidemiological monitoring of the H10N8 influenza virus in different animal species, which will be helpful for preventing and controlling future infections by this virus.

Physicochemical Characterization of a Polysaccharide from Green Microalga Chlorella pyrenoidosa and Its Hypolipidemic Activity via Gut Microbiota Regulation in Rats.

A bioactive polysaccharide from microalga Chlorella pyrenoidosa (CPP) was successively prepared via DEAE-52 and G-100 columns. Nuclear magnetic resonance analysis showed that the main glycosidic bonds were composed of 1,2-linked-α-l-Fucp, 1,4-linked-α-l-Rhap, 1,4-linked-ß-l-Araf, 1-linked-α-d-Glcp, 1,3-linked-ß-d-GlcpA, 1,4-linked-ß-d-Xylp, and 1,3,6-linked-ß-d-Manp. Its molecular weight was 5.63 × 106 Da. The hypolipidemic effect and intestinal flora regulation of CPP on diet-induced rats were evaluated through histopathology and biochemistry analyses. CPP could improve plasma and liver lipid metabolism and accelerate the metabolism of the cecal total bile acids and short-chain fatty acids. CPP has also upregulated the adenosine-monophosphate-activated protein kinase α and downregulated the acetyl-CoA carboxylase, sterol regulatory element-binding protein 1c, and ß-hydroxy ß-methylglutaryl-CoA expressions. Moreover, with the 16S rRNA gene sequencing, it was revealed that the composition of intestinal flora changed drastically after treatment, such as the bloom of Coprococcus_1, Lactobacillus, and Turicibacter, whereas there was a strong reduction of the [Ruminococcus]_gauvreauii_group. The above results illustrated that CPP might be served as an effective ingredient to ameliorate lipid metabolism disorders and intestinal flora in hyperlipidemia rats.

The R251K Substitution in Viral Protein PB2 Increases Viral Replication and Pathogenicity of Eurasian Avian-like H1N1 Swine Influenza Viruses.

The Eurasian avian-like swine (EA) H1N1 virus has affected the Chinese swine industry, and human infection cases have been reported occasionally. However, little is known about the pathogenic mechanism of EA H1N1 virus. In this study, we compared the mouse pathogenicity of A/swine/Guangdong/YJ4/2014 (YJ4) and A/swine/Guangdong/MS285/2017 (MS285) viruses, which had similar genotype to A/Hunan/42443/2015 (HuN-like). None of the mice inoculated with 106 TCID50 of YJ4 survived at 7 days post infection, while the survival rate of the MS285 group was 100%. Therefore, a series of single fragment reassortants in MS285 background and two rescued wild-type viruses were generated by using the reverse genetics method, and the pathogenicity analysis revealed that the PB2 gene contributed to the high virulence of YJ4 virus. Furthermore, there were 11 amino acid differences in PB2 between MS285 and YJ4 identified by sequence alignment, and 11 single amino acid mutant viruses were generated in the MS285 background. We found that the R251K mutation significantly increased the virulence of MS285 in mice, contributed to high polymerase activity and enhanced viral genome transcription and replication. These results indicate that PB2-R251K contributes to the virulence of the EA H1N1 virus and provide new insight into future molecular epidemiological surveillance strategies.

Nutrient Properties and Nuclear Magnetic Resonance-Based Metabonomic Analysis of Macrofungi.

Many delicious and nutritional macrofungi are widely distributed and used in East Asian regions, considered as edible and medicinal foods. In this study, 11 species of dried and fresh, edible and medicinal macrofungi, Ganoderma amboinense, Agaricus subrufescens, Dictyophora indusiata, Pleurotus sajor-caju, Pleurotus ostreatus, Pleurotus geesteranu, Hericium erinaceus, Stropharia rugosoannulata, Pleurotus sapidus, Antrodia camphorata, and Lentinus edodes (Berk.) Sing, were investigated to determine the content of their nutritional components, including proteins, fat, carbohydrates, trace minerals, coarse cellulose, vitamins, and amino acids. The amino acid patterns and similarity of macrofungi were distinguished through principal component analysis and hierarchical cluster analyses, respectively. A total of 103 metabolic small molecules of macrofungi were identified by nuclear magnetic resonance spectroscopy and were aggregated by heatmap. Moreover, the macrofungi were classified by principal component analysis based on these metabolites. The results show that carbohydrates and proteins are two main components, as well as the nutritional ingredients, that differ among various species and varied between fresh and dried macrofungi. The amino acid patterns in L. edodes and A. subrufescens were different compared with that of the other tested mushrooms.

Hypoglycemic activity and gut microbiota regulation of a novel polysaccharide from Grifola frondosa in type 2 diabetic mice.

GFP-N, a novel heteropolysaccharide with a molecular weight of 1.26 × 107 Da, was isolated from maitake mushroom and purified by anion-exchange chromatography on a DEAE cellulose-52 column and gel-filtration chromatography on a Sephadex G-100 column. Its structure was characterized by Fourier transform infrared spectroscopy and one-dimensional (1H- and 13C-) NMR spectra, 1H1H correlation spectroscopy, and 1H13C heteronuclear single-quantum coherence spectroscopy. The structure of GFP-N consisted of L-arabinose, D-mannose and D-glucose and mainly contained three kinds of linkage type units as →2,6)-α-D-Manp-(1 → 4, α-L-Araf-C1→, and →3,6)-ß-D-Glcp-(1 → . GFP-N could activate insulin receptor substrate 1, phosphatidylinositol-3-kinase, and glucose transporter 4 and inhibit c-Jun N-terminal kinase 1/2 for hypoglycemic effects in diabetic mouse livers. This is also the first report of the regulatory efficacy of Grifola frondosa polysaccharide on intestinal microflora in vivo using single-molecule real-time sequencing. These results indicated that polysaccharide from maitake mushroom could be as an enhancer to improve type 2 diabetes and a healthy food option to help regulate gut microbiota in diabetic individuals.

Anti-diabetic activity of PUFAs-rich extracts of Chlorella pyrenoidosa and Spirulina platensis in rats.

The contributions to hypoglycemic function and gut microbiota regulation by water and ethanol extracts of the microalgae Chlorella pyrenoidosa and Spirulina platensis were determined. An ultra-high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry analysis indicated that most of the compounds in the 55% ethanol extracts of C. pyrenoidosa (CP55) and S. platensis (SP55) were polyunsaturated fatty acids. After an 8-week high-fat high-sucrose diet with C. pyrenoidosa and S. platensis supplementation, glucose tolerance was improved, and the composition of the gut microbiota was altered. The diversity of the gut bacterial community was evaluated using 16S rRNA gene pyrosequencing. C. pyrenoidosa supplementation increased the abundance of Ruminococcus, Parasutterella, and Erysipelotrichacea and decreased the abundance of Lactobacillus, Turicibacter, and Blautia; S. platensis supplementation increased the abundance of Oscillibacter, Parasutterella, and Alloprevotella and decreased the abundance of Turicibacter. Moreover, Erysipelotrichacea and Ruminococcus were uniquely increased in C. pyrenoidosa treatment groups. Thus, CP55 and SP55 may be developed as effective natural food materials for preventing diabetes, and Ruminococcus may play a vital role in the treatment of diabetes.

Ginsenoside Rg1 Suppresses Type 2 PRRSV Infection via NF-κB Signaling Pathway In Vitro, and Provides Partial Protection against HP-PRRSV in Piglet.

Porcine reproductive and respiratory syndrome virus (PRRSV) is a huge threat to the modern pig industry, and current vaccine prevention strategies could not provide full protection against it. Therefore, exploring new anti-PRRSV strategies is urgently needed. Ginsenoside Rg1, derived from ginseng and notoginseng, is shown to exert anti-inflammatory, neuronal apoptosis-suppressing and anti-oxidant effects. Here we demonstrate Rg1-inhibited PRRSV infection both in Marc-145 cells and porcine alveolar macrophages (PAMs) in a dose-dependent manner. Rg1 treatment affected multiple steps of the PRRSV lifecycle, including virus attachment, replication and release at concentrations of 10 or 50 µM. Meanwhile, Rg1 exhibited broad inhibitory activities against Type 2 PRRSV, including highly pathogenic PRRSV (HP-PRRSV) XH-GD and JXA1, NADC-30-like strain HNLY and classical strain VR2332. Mechanistically, Rg1 reduced mRNA levels of the pro-inflammatory cytokines, including IL-1ß, IL-8, IL-6 and TNF-α, and decreased NF-κB signaling activation triggered by PRRSV infection. Furthermore, 4-week old piglets intramuscularly treated with Rg1 after being challenged with the HP-PRRSV JXA1 strain display moderate lung injury, decreased viral load in serum and tissues, and an improved survival rate. Collectively, our study provides research basis and supportive clinical data for using Ginsenoside Rg1 in PRRSV therapies in swine.