Discovery of Antifungal Norsesquiterpenoids from a Soil-Derived Streptomyces microflavus: Targeting Biofilm Formation and Synergistic Combination with Amphotericin B against Yeast-like Fungi.

Thirty-five norsesquiterpenoids were isolated from the fermentation broth of Streptomyces microflavus from the forest soil of Ailaoshan in China. The structures of new compounds (1-5, 10-26) were elucidated by comprehensive spectroscopic analysis including data from experimental and calculated ECD spectra, as well as Mosher's reagent derivatives method. Norsesquiterpenoids showed different levels of antifungal activity with MIC80 values ranging from 25 to 200 µg/mL against Candida albicans, Candida parapsilosis, and Cryptococcus neoformans. The combining isolated norsesquiterpenoids with amphotericin B resulted in a synergistic interaction against test yeast-like fungi with a fractional inhibitory concentration index < 0.5. Compound 33 significantly inhibited biofilm formation and destroyed the preformed biofilm of fungi. Moreover, 33 downregulated the expression of adhesion-related genes HWP1, ALS1, ALS3, ECE1, EAP1, and BCR1 to inhibit the adhesion of C. albicans. Findings from the current study highlight the potential usage of norsesquiterpenoids from soil-derived Streptomyces for antifungal leads discovery.

Structure-activity relationship and biofilm formation-related gene targets of oleanolic acid-type saponins from Pulsatilla chinensis against Candida albicans.

In the course of our investigations of antifungal natural products, the structure-activity relationship and antifungal activities of oleanolic acid-type saponins (1-28) from Pulsatilla chinensis against human and plant pathogenic fungi were elucidated. The analysis of structure-activity relationship of oleanolic acid-type saponins showed that the free carboxyl at C-28 was essential for their antifungal activities; the free hydroxyl group at the C-23 site of oleanolic acid-type saponins played a crucial role in their antifungal activities; the oligosaccharide chain at C-3 oleanolic acid-type saponins showed significant effects on antifungal efficacy and a disaccharide or trisaccharide moiety at position C-3 displayed optimal antifungal activity. The typical saponin pulchinenoside B3 (16, PB3) displayed satisfactory antifungal activity against human and plant pathogenic fungi, especially, C. albicans with an MIC value of 12.5 µg/mL. Furthermore, PB3 could inhibit the biofilm formation of C. albicans through downregulating the expression of the integrated network of biofilm formation-associated transcription factors (Bcr1 Efg1, Ndt80, Brg1, Rob1 and Tec1) and adhesion-related target genes (HWP1, ALS1, and ALS3). Meanwhile, we found that PB3 could effectively destroy the mature biofilm of C. albicans by the oxidative damage and inducing mitochondria-mediated apoptosis in cells.

Discovery, synthesis, and cytotoxic evaluation of isoquinolinequinones produced by Streptomyces albidoflavus derived from lichen.

Four isoquinolinequinones (1-4) were isolated from the fermentation broth of Streptomyces albidoflavus which were derived from lichens. Among them, mansouramycin H (1) was identified as a new isoquinolinequinone by comprehensive spectroscopic data analysis. The mansouramycins from S. albidoflavus presented broad cytotoxic activities, especially against MDA-MB-231, but the SAR and mechanism were still unclear. The total synthesis of mansouramycin H (1) and its twenty-three derivatives were completed and their cytotoxic activities against MDA-MB-231 were evaluated in vitro. Primary SAR revealed that the piperazine moieties introduced into the amino group at C-7 could improve the activities of mansouramycins. Benzoyl and phenylacetyl groups on piperazine fragments had better activities than those of benzyl substitution; the alkyl substituent on piperazine exhibited optimal activity. Among them, compound 1g showed the strongest cytotoxicity against MBA-MB-231 cells with an IC50 value of 5.12 ± 0.11 µM. Mechanistic studies revealed that 1g induced apoptosis in MBA-MB-231 cells through down-regulating the protein expression of Bcl-2, up-regulating the protein expression of bax, and, meanwhile, activating the cleavage of caspase-3 and caspase-9. 1g caused S phase cell cycle arrest in MBA-MB-231 cells by reducing the protein expression of CDK2 and cyclin A2 and increasing the protein levels of p21.

Senkyunolide B exhibits broad-spectrum antifungal activity against plant and human pathogenic fungi via inhibiting spore germination and destroying the mature biofilm.

BACKGROUND: Aspergillus infection seriously jeopardizes the health and safety of life of immunocompromised patients. The emergences of antifungal resistance highlight a demand to find new effective antifungal drugs. Angelica sinensis is a medicine-food herb and phthalides are its characteristic components. A few of the phthalides have been reported to display satisfactory antifungal activities against plant pathogenic fungi. However, the structure-activity relationships and antifungal action mechanism of phthalides remain to be further explored and elucidated. RESULTS: The antifungal activities of five natural phthalides and four artificial analogs were investigated, and their structure-activity relationships were preliminarily elucidated in the current study. The benzene ring moiety played an essential role in their antifungal activities; the oxygen-containing substituents on the benzene ring obviously impacted their activities, the free hydroxyl was favorable to the activity. Typical phthalide senkyunolide B (SENB) exhibited broad antifungal activities against human and plant pathogenic fungi, especially, Aspergillus fumigatus. SENB affected the spore germination and hyphae growth of Aspergillus fumigatus via down-regulating phosphatidylinositol-PKC-calcineurin axis and the expression of ENG genes. Moreover, SENB disturbed the oxidation-reduction process in Aspergillus fumigatus to destroy the mature biofilms. In vivo experiments indicated SENB significantly prolonged survival and decreased fungal burden in mouse model of invasive pulmonary aspergillosis. CONCLUSIONS: Phthalides could be considered as the valuable leads for the development of antifungal drug to cure plant and human disease. © 2023 Society of Chemical Industry.

Levistolide A ameliorates fibrosis in chronic kidney disease via modulating multitarget actions in vitro and in vivo.

AIMS: The increasing incidence of chronic kidney disease (CKD) urgently calls for effective nephroprotective agents. Traditional Chinese Medicine Angelica sinensis and its formula are well known for CKD therapy, but the underlying mechanisms and effective substances of reno-protective effects remain unclear. To this end, we isolated eleven ligustilide dimers (1-11) from A. sinensis and examined the molecular mechanism of their nephroprotective effects. MAIN METHODS: Because of internal RAS playing an important role in CKD, we used renin expression as a target and screened preliminarily for antifibrotic effects of ligustilide dimers (1-11) by constructing a dual luciferase reporter gene in vitro. Furthermore, the reno-protective effects of the ligustilides and their underlying mechanism were investigated in TGF-ß1-stimulated HK-2 cells and 5/6 nephrectomy (Nx) mice. KEY FINDINGS: The ligustilide dimers exhibited anti-fibrotic effects by inhibiting human renin (hREN) promoter activity to decrease renin expression and down-regulate the expression of fibrosis-related factors, including α-SMA, collagen I, and fibronectin in vitro. Levistolide A (LA) and angeolide keto ester (AK) were screened out to identify their ability and underlying mechanism for treating CKD. Experimental validation further indicated that LA or AK treatment inhibited the expression of key molecules in RAS, TGF-ß1/Smad, and MAPK pathways to downregulate ECM deposition. Furthermore, LA obviously meliorated renal injury in 5/6 Nx mice through ameliorating oxidant stress, inflammation, apoptosis and renal fibrosis. SIGNIFICANCE: The experimental results demonstrated that ligustilide dimers were potential nephroprotective agents. LA might be an attractive drug candidate for renin-targeted CKD therapy.

Discovery, Preliminary Structure-Activity Relationship, and Evaluation of Oleanane-Type Saponins from Pulsatilla chinensis for the Treatment of Ulcerative Colitis.

To discover ulcerative colitis (UC) treatment agents, 28 oleanane-type triterpenoid saponins (1-28) including three new saponins, pulsatillosides P-R (1-3), were isolated from Pulsatilla chinensis. The isolated saponins could observably ameliorate UC by improving the intestinal epithelial cell barrier and intestinal flora in vivo. The structure-activity relationship indicated that the oligosaccharide chain at C-28 was essential for their anti-UC activities; the methyl group at the C-23 site of triterpene saponins showed important effects on anti-UC efficacy; the chain length of oligosaccharides at position C-28 had little effect on their anti-UC activities. In vivo investigation of representative saponins 1 and 13 further confirmed that 23-methyl-3,28-bisdesmosidic oleanane-type saponins inhibited the TNFα-NFκB-MLCK axis to improve the intestinal epithelial cell barrier of the colon in UC mice. These findings revealed the potential of 23-methyl-3,28-bisdesmosidic oleanane-type saponins from P. chinensis as promising candidates for the treatment of UC.

Phenolipid JE improves metabolic profile and inhibits gluconeogenesis via modulating AKT-mediated insulin signaling in STZ-induced diabetic mice.

Phenolipids are characteristic phytochemicals of Syzygium genus. However, the antidiabetic potential and underlying molecular mechanism of these components are not fully elucidated. Herein, we studied the anti-diabetic effects of jambone E (JE), a phenolipid from S. cumini, with in vitro and in vivo models. Data from current study showed that JE enhanced glucose consumption and uptake, promoted glycogen synthesis, and suppressed gluconeogenesis in insulin resistant (IR)-HepG2 cells and primary mouse hepatocytes. JE also attenuated streptozotocin-induced hyperglycemia and hyperlipidemia in type 1 diabetic (T1D) mice. Eleven metabolites (e.g. trimethylamine n-oxide, 4-pyridoxic acid, phosphatidylinositol 39:4, phenaceturic acid, and hippuric acid) were identified as potential serum biomarkers for JE's antidiabetic effects by an untargeted metabolomics approach. The further molecular mechanistic study revealed that JE up-regulated phosphorylation levels of protein kinase B (AKT), glycogen synthase kinase 3 beta, and forkhead box O1 (FoxO1), promoted nuclear exclusion of FoxO1 whilst decreased gene expression levels of peroxisome proliferator-activated receptor gamma coactivator-1 alpha, phosphoenolpyruvate carboxykinase and glucose 6-phosphatase in IR-HepG2 cells and T1D mice. Our data suggested that JE might be a potent activator for AKT-mediated insulin signaling pathway, which was confirmed by the usage of AKT inhibitor and AKT-target siRNA interference, as well as the cellular thermal shift assay. Findings from the current study shed light on the anti-diabetic effects of phenolipids in the Syzygium species, which supports the use of medicinal plants in the Syzygium genus for potential pharmaceutical applications.

The Anti-inflammatory Effects of Isoflavonoids from Radix Astragali in Hepatoprotective Potential against LPS/D-gal-induced Acute Liver Injury.

Radix Astragali (RA) is an important Traditional Chinese Medicine widely used in the treatment of various diseases, such as pneumonia, atherosclerosis, diabetes, kidney and liver fibrosis. The role of isoflavonoids from RA in the treatment of liver injury remains unclear. The study aimed to explore hepatoprotective and anti-inflammatory effects of isoflavonoids from Astragalus mongholicus. Network pharmacological analysis showed that RA had a multi-target regulating effect on alleviating liver injury and inhibiting inflammation through its active ingredients, among which isoflavones were closely related to its key molecular targets. The anti-inflammatory and liver protection effects of isoflavonoids of RA were investigated using lipopolysaccharide (LPS)-induced RAW 264.7 cells in vitro and LPS/D-galactosamine (D-gal)-induced acute liver injury mice in vivo. The experimental results showed that methylnissolin (ML) and methylnissolin-3-O-ß-D-glucoside (MLG) presented more notable anti-inflammatory effects. Both of them suppressed the release of pro-inflammatory cytokines, such as iNOS, COX-2, IL-1ß, IL-6, and TNF-α in LPS-stimulated RAW 264.7 cells. In vivo investigation demonstrated that ML markedly meliorated liver injury in LPS/D-gal-induced mice. Western blot results revealed that ML and MLG down-regulated the expression of proinflammatory cytokines via NF-κB signaling pathway. The isoflavonoids, methylnissolin (ML), and methylnissolin-3-O-ß-D-glucoside (MLG), play a vital role in the hepatoprotective and anti-inflammatory effects of RA.

Discovery of antibacterial agents targeting biofilm formation: total synthesis and in vitro investigation of amycolasporins.

Three monoterpene alkaloids amycolasporin A and (±) amycolasporins B and C have been synthesized for the first time from commercially available materials in yields of 31%, 14% and 21%, respectively. Their six analogues (18, 19, 30a and 30d-30f) were synthesized through a similar protocol. Meanwhile, the antibacterial activity of all synthesized molecules was evaluated, showing different levels of bioactivity. Among them, analogue 30d was screened as the most effective antibacterial candidate against E. coli (MIC value, 12.5 µg mL-1) and S. aureus (MIC value, 12.5 µg mL-1). Further investigation showed that 30d obviously inhibited biofilm formation and disrupted the preformed biofilm of E. coli and S. aureus by promoting intracellular ROS release.

Novel melatonin-trientine conjugate as potential therapeutic agents for Alzheimer's disease.

Researchers continue to explore drug targets to treat the characteristic pathologies of Alzheimer's disease (AD). Some drugs relieve the pathological processes of AD to some extent, but the failed clinical trials indicate that multifunctional agents seem more likely to achieve the therapy goals for this neurodegenerative disease. Herein, a novel compound named melatonin-trientine (TM) has been covalently synthesized with the natural antioxidant compounds melatonin and the metal ion chelator trientine. After toxicological and pharmacokinetic verification, we elucidated the effects of intraperitoneal administration of TM on AD-like pathology in 6-month-old mice that express both the ß-amyloid (Aß) precursor protein and presenilin-1 (APP/PS1). We found that TM significantly decreased Aß deposition and neuronal degeneration in the brains of the APP/PS1 double transgenic mice. This result may be due to the upregulation of iron regulatory protein-2 (IRP2), insulin degrading enzyme (IDE), and low density lipoprotein receptor related protein 1 (LRP1), which leads to decreases in APP and Aß levels. Additionally, TM may promote APP non-amyloidogenic processing by activating the melatonin receptor-2 (MT2)-dependent signaling pathways, but not MT1. In addition, TM plays an important role in blocking γ-secretase, tau hyperphosphorylation, neuroinflammation, oxidative stress, and metal ion dyshomeostasis. Our results suggest that TM may effectively maximize the therapeutic efficacy of targeting multiple mechanisms associated with AD pathology.

Comparative and functional analyses of fecal microbiome in Asian elephants.

Asian elephant is large herbivorous animal with elongated hindgut. To explore fecal microbial community composition with various ages, sex and diets, and their role in plant biomass degrading and nutrition conversation. We generated 119 Gb by metagenome sequencing from 10 different individual feces and identified 5.3 million non-redundant genes. The comprehensive analysis established that the Bacteroidetes, Firmicutes and Proteobacteria constituted the most dominant phyla in overall fecal samples. In different individuals, the alpha diversity of the fecal microbiota in female was lower than male, and the alpha diversity of the fecal microbiota in older was higher than younger, and the fecal microbial diversity was the most complex in wild elephant. But the predominant population compositions were similar to each other. Moreover, the newborn infant elephant feces assembled and maintained a diverse but host-specific fecal microbial population. The discovery speculated that Asian elephant maybe have start to building microbial populations before birth. Meanwhile, these results illustrated that host phylogeny, diets, ages and sex are significant factors for fecal microbial community composition. Therefore, we put forward the process of Asian elephant fecal microbial community composition that the dominant populations were built first under the guidance of phylogeny, and then shaped gradually a unique and flexible gut microbial community structure under the influences of diet, age and sex. This study found also that the Bacteroidetes were presumably the main drivers of plant fiber-degradation. A large of secondary metabolite biosynthetic gene clusters, and genes related to enediyne biosynthesis were found and showed that the Asian elephant fecal microbiome harbored a diverse and abundant genetic resource. A picture of antibiotic resistance genes (ARGs) reservoirs of fecal microbiota in Asian elephants was provided. Surprisingly, there was such wide range of ARGs in newborn infant elephant. Further strengthening our speculation that the fetus of Asian elephant has colonized prototypical fecal microbiota before birth. However, it is necessary to point out that the data give a first inside into the gut microbiota of Asian elephants but too few individuals were studied to draw general conclusions for differences among wild and captured elephants, female and male or different ages. Further studies are required. Additionally, the cultured actinomycetes from Asian elephant feces also were investigated, which the feces of Asian elephants could be an important source of actinomycetes.

Discovery, preparation and characterization of lipid-lowering alkylphenol derivatives from Syzygium jambos fruit.

The chemical characteristics and hypolipidemic effects of alkylphenols in the fruit of Syzygium jambos were investigated in this study. Three cardanols (1-3; 1 as a new compound) and three alkylresorcinols (4-6) were isolated and identified from S. jambos fruit. Cardanols 1 and 2 (10-40 µM) suppressed lipids accumulation and reduced triglyceride content in oleic acid-overloaded HepG2 cells via the activation of AMPK/PPARα signaling pathways. Furthermore, the biological distribution of cardanols after an oral intake in mice was investigated. Compound 2 was detected in mice plasma, feces, and adipose tissues after a single oral intake (80 mg/kg body weight). In addition, an alkylphenols-enriched S. jambos fruit extract containing two bioactive compounds (95.9 and 198.6 µg/mg of compounds 1 and 2, respectively) was prepared. Findings from the current study highlight the potential usage of cardanols as well as S. jambos fruit for the management of dyslipidemia.

The crude guava polysaccharides ameliorate high-fat diet-induced obesity in mice via reshaping gut microbiota.

Guava is a popular fruit consumed worldwide with beneficial effects in regulation of glucose and lipid metabolism. Although polysaccharides are a major phytochemical component of guava, to date, the alleviative effects of polysaccharides from the guava fruit against diet-induced obesity remain unclear. The relationship between the anti-obesity effects of guava polysaccharide (GP) and gut microbiota is unknown. In current study, seven-week-old C57BL/6 mice were fed high-fat diet (HFD) supplemented with GP (100 mg/kg) by oral gavage for 11 weeks. GP supplementation alleviated HFD-induced body weight gain and visceral obesity, and reduced serum cholesterol, triglyceride, and LDL-C levels. In addition, GP ameliorated insulin resistance and prevented hepatic lipid accumulation and meta-inflammation in both liver and adipose tissues in obese mice. Remarkably, GP treatment restored the Firmicutes/Bacteroidetes ratio, induced growth of beneficial bacteria including Clostridium XlVa, Parvibacter, and Enterorhabdus, and decreased in inflammation-related bacteria Mucispirillum in mice fecal samples, accompanied with enhanced production of colonic short chain fatty acids especially butyric acid. However, the metabolic benefits of GP diminished in antibiotics-treated HFD-fed mice. Overall, GP improved metabolic profiles in HFD-induced obese mice via the mediation of gut microbiota-dependent pathways. GP might be developed and utilized as prebiotics in nutraceutical and food industry.

The discovery of germacradienol synthase: Construction of genetically-engineered strain, glycosylated modification, bioactive evaluation of germacradienol.

Germacradienol is a main precursor in the biosynthesis of geosmin-type terpenes by a variety of microbes, but its biological activities are still unknown. In the biosynthetic mechanism study of an antifungal degraded sesquiterpenoid (1ß,4ß,4aß,8aα)-4,8a-dimethyloctahydronaphthalene-1,4a(2H)-diol (5) with a geosmin scaffold, the germacradienol synthase B7C62_00490 was identified. To exploit the synthetic potential of the enzyme to create germacradienol, engineered strains were constructed by introducing key synthases of farnesyl diphosphate, germacradienol synthase B7C62_00490 and glycosyltransferase UGT73C5 in Escherichia coli BL21(DE3). Germacradienol (1) and the novel glycosylated derivate germacradienyl-11-O-ß-d-glucopyranoside (3) were successfully obtained from engineered strains. The cytotoxic activity against nine human cancer cell lines and antimicrobial activities against a panel of bacteria and fungi of germacradienol analogs derived from engineered strains were evaluated. Germacradienol demonstrated multiple biological activities, including broad antimicrobial activities with MIC values ranging from 12.5 to 25.0 µg/mL and cytotoxic activities with IC50 values ranging from 21.0 to 83.5 µM. However, the glycosylated germacradienol was inactive.

Effect of Fufang Huangqi Decoction on the Gut Microbiota in Patients With Class I or II Myasthenia Gravis.

Objective: To investigate the effect of Fufang Huangqi Decoction on the gut microbiota in patients with class I or II myasthenia gravis (MG) and to explore the correlation between gut microbiota and MG (registration number, ChiCTR2100048367; registration website, http://www.chictr.org.cn/listbycreater.aspx; NCBI: SRP338707). Methods: In this study, microbial community composition and diversity analyses were carried out on fecal specimens from MG patients who did not take Fufang Huangqi Decoction (control group, n = 8) and those who took Fufang Huangqi Decoction and achieved remarkable alleviation of symptoms (medication group, n = 8). The abundance, diversity within and between habitats, taxonomic differences and corresponding discrimination markers of gut microbiota in the control group and medicated group were assessed. Results: Compared with the control group, the medicated group showed a significantly decreased abundance of Bacteroidetes (P < 0.05) and significantly increased abundance of Actinobacteria at the phylum level, a significantly decreased abundance of Bacteroidaceae (P < 0.05) and significantly increased abundance of Bifidobacteriaceae at the family level and a significantly decreased abundance of Blautia and Bacteroides (P < 0.05) and significantly increased abundance of Bifidobacterium, Lactobacillus and Roseburia at the genus level. Compared to the control group, the medicated group had decreased abundance, diversity, and genetic diversity of the communities and increased coverage, but the differences were not significant (P > 0.05); the markers that differed significantly between communities at the genus level and influenced the differences between groups were Blautia, Bacteroides, Bifidobacterium and Lactobacillus. Conclusions: MG patients have obvious gut microbiota-associated metabolic disorders. Fufang Huangqi Decoction regulates the gut microbiota in patients with class I or II MG by reducing the abundance of Blautia and Bacteroides and increasing the abundance of Bifidobacterium and Lactobacillus. The correlation between gut microbiota and MG may be related to cell-mediated immunity.

New Monoterpene Acid and Gallic Acid Glucose Esters with Anti-Inflammatory Activity from Blue Gum (Eucalyptus globulus) Leaves.

Blue gum (Eucalyptus globulus) is a widely used botanical in the cosmeceutical and food industries. Although blue gum leaves are known for abundant essential oils, their nonvolatile phytochemical constituents and bioactivities remain unclear. Herein, a phytochemical investigation of blue gum leaves led to the identification of eight new monoterpene acid and gallic acid glucose esters (1-4 and 14-17; glubosides A-H, respectively) and 12 known analogues (5-13 and 18-20). Their structures were determined based on extensive spectroscopic data analysis, chemical degradation, and chiral separation. Oleuropeic acid conjugated glucose esters (1-13, 15, 16, 18, and 20) are reported as epimeric mixtures. Compounds 7, 12, 14, 19, and 20 (at 30 µM) inhibited nitrite release in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Compounds 7 and 14 (at 3-30 µM) also down-regulated proinflammatory biomarkers, including cytokines (TNF-α, IL-6, and IL-1ß), protein expression (iNOS and COX-2), and transcription factor nuclear translocation (NF-κB) in LPS-stimulated RAW264.7 cells. This work highlights the anti-inflammatory potential of phytochemicals from blue gum leaves, which supports their further development as cosmeceutical and/or nutraceutical products.

New phenolic glycosides from Anemone chinensis Bunge and their antioxidant activity.

ABATRACTNine compounds, five phenolic glycosides (1, 2, 4-6), three phenylpropanoids (7-9), and a furanone glycoside (3), were isolated from aqueous soluble extract of the dried roots of Anemone chinensis Bunge. The structures of new compounds (1-4) were elucidated by comprehensive spectroscopic data analysis as well as chemical evidence. Pulsatillanin A (1) demonstrated significant antioxidant effects through scavenging free radical in DPPH assay, and relieved the oxidative stress in LPS-induced RAW 264.7 cells by reducing ROS production, enhancing antioxidant enzyme SOD activity, replenishing depleted GSH in a dose-dependent manner. Western blot analysis revealed that 1 showed antioxidant activity via activating Nrf2 signaling pathway.[Formula: see text].

Riligustilide alleviates hepatic insulin resistance and gluconeogenesis in T2DM mice through multitarget actions.

Riligustilide (RG), one of the dimeric phthalides of Angelica sinensis and Ligusticum chuanxiong, was confirmed effective against many diseases. However, its effects on type 2 diabetes mellitus (T2DM) and the underlying molecular mechanisms have not been clearly elucidated yet. The current study was designed to investigate the hypoglycemic potential by which RG affects the pathogenesis of T2DM. Comprehensive insights into the effects and underlying molecular mechanisms of RG on attenuating aberrant metabolism of glucose were determined in high-fat diet-induced T2DM mice and insulin-resistant (IR) HepG2 cells. In high-fat diet-induced C57BL/6J mice, RG administration significantly reduced hyperglycemia, decreased hyperinsulinemia, and ameliorated glucose intolerance. Mechanistically, RG activated PPARγ and insulin signaling pathway to improve insulin sensitivity, and increase glucose uptake as well as glycogenesis. In addition, RG also upregulated AMPK-TORC2-FoxO1 axis to attenuate gluconeogenesis in vivo and in vitro. According to the findings, RG may be a promising candidate for the treatment of T2DM.

Downregulating expression of OPTN elevates neuroinflammation via AIM2 inflammasome- and RIPK1-activating mechanisms in APP/PS1 transgenic mice.

BACKGROUND: Neuroinflammation is thought to be a cause of Alzheimer's disease (AD), which is partly caused by inadequate mitophagy. As a receptor of mitophagy, we aimed to reveal the regulatory roles of optineurin (OPTN) on neuroinflammation in the pathogenesis of AD. METHODS: BV2 cells and APP/PS1 transgenic (Tg) mice were used as in vitro and in vivo experimental models to determine the regulatory roles of OPTN in neuroinflammation of AD. Sophisticated molecular technologies including quantitative (q) RT-PCR, western blot, enzyme linked immunosorbent assay (ELISA), co-immunoprecipitation (Co-IP) and immunofluorescence (IF) were employed to reveal the inherent mechanisms. RESULTS: As a consequence, key roles of OPTN in regulating neuroinflammation were identified by depressing the activity of absent in melanoma 2 (AIM2) inflammasomes and receptor interacting serine/threonine kinase 1 (RIPK1)-mediated NF-κB inflammatory mechanisms. In detail, we found that expression of OPTN was downregulated, which resulted in activation of AIM2 inflammasomes due to a deficiency in mitophagy in APP/PS1 Tg mice. By ectopic expression, OPTN blocks the effects of Aß oligomer (Aßo) on activating AIM2 inflammasomes by inhibiting mRNA expression of AIM2 and apoptosis-associated speck-like protein containing a C-terminal caspase recruitment domain (ASC), leading to a reduction in the active form of caspase-1 and interleukin (IL)-1ß in microglial cells. Moreover, RIPK1 was also found to be negatively regulated by OPTN via ubiquitin protease hydrolysis, resulting in the synthesis of IL-1ß by activating the transcriptional activity of NF-κB in BV2 cells. As an E3 ligase, the UBAN domain of OPTN binds to the death domain (DD) of RIPK1 to facilitate its ubiquitination. Based on these observations, ectopically expressed OPTN in APP/PS1 Tg mice deactivated microglial cells and astrocytes via the AIM2 inflammasome and RIPK-dependent NF-κB pathways, leading to reduce neuroinflammation. CONCLUSIONS: These results suggest that OPTN can alleviate neuroinflammation through AIM2 and RIPK1 pathways, suggesting that OPTN deficiency may be a potential factor leading to the occurrence of AD.

Chemical characterization, antiproliferative and antifungal activities of Clinacanthus nutans.

Clinacanthus nutans Lindau (Family: Acanthaceae) is a medicinal herb widely distributed in the tropic and subtropic areas of Asia. C. nutans is traditionally consumed as vegetable or herbal tea, as well as a folk medicine for anticancer and antifungal activities. However, to date, chemical constituent responsible for observed health beneficial effects of this medicinal plant is not clear. In the current study, 32 compounds (1-32), including three new megastigmanes (1-3) were isolated from the aerial parts of C. nutans. Their structures were elucidated on the basis of comprehensive NMR, MS, and CD spectroscopic data analysis, as well as chemical hydrolysis. Among the isolates, cycloartane triterpenoids (9, 10, and 12) displayed moderate anti-proliferative effects against HepG2 cell growth with IC50 values ranging from 9.12 to 19.89 µM. Data obtained from flow cytometry analysis and western blotting assays revealed that compounds 9 and 12 induced apoptosis of HepG2 cells by modulating the expression of proteins associated to mitochondrial-mediated apoptotic pathway. Furthermore, megastigmanes 1, 2, 7, and 8 enhanced the anti-Candida albicans activity of amphotericin B (AmB), supporting the synergistic effects between megastigmanes and AmB. This is the first report of anticancer and antifungal potential of cycloartane triterpenoids and megastigmanes in C. nutans, which shed useful insights on the relationship between C. nutans's chemical constituent and its beneficial effects to health. Findings from this study support further development of this medicinal plant for potential pharmaceutical applications.