Sarmentol H derived from Sedum sarmentosum Bunge directly targets FXR to mitigate cholestasis by recruiting SRC-1.

BACKGROUND: Farnesoid X receptor (FXR) is a vital receptor for bile acids and plays an important role in the treatment of cholestatic liver disease. In addition to traditional bile acid-based steroidal agonists, synthetic alkaloids are the most commonly reported non-steroidal FXR agonists. Sarmentol H is a nor-sesquiterpenoid obtained from Sedum sarmentosum Bunge, and in vitro screening experiments have shown that it might be related to the regulation of the FXR pathway in a previous study. PURPOSE: To investigate the therapeutic effects of sarmentol H on cholestasis and to determine whether sarmentol H directly targets FXR to mitigate cholestasis. Furthermore, this study aimed to explore the key amino acid residues involved in the binding of sarmentol H to FXR through site-directed mutagenesis. METHODS: An intrahepatic cholestasis mouse model was established to investigate the therapeutic effects of sarmentol H on cholestasis. In vitro experiments, including Co-Ip and FXR-EcRE-Luc assays, were performed to assess whether sarmentol H activates FXR by recruiting the receptor coactivator SRC1. CETSA, SIP, DARTS, and ITC were used to determine the binding of sarmentol H to FXR protein. The key amino acid residues for sarmentol H binding to FXR were analyzed by molecular docking and site-directed mutagenesis. Finally, we conducted in vivo experiments on wild-type and Fxr-/- mice to further validate the anticholestatic target of sarmentol H. RESULTS: Sarmentol H had significant ameliorative effects on the pathological conditions of cholestatic mice induced with ANIT. In vitro experiments suggested that it is capable of activating FXR and regulating downstream signaling pathways by recruiting SRC1. The target validation experiments showed that sarmentol H had the ability to bind to FXR as a ligand (KD = 2.55 µmol/L) and enhance the stability of its spatial structure. Moreover, site-directed mutagenesis revealed that THR292 and TYR365 were key binding sites for sarmentol H and FXR. Furthermore, knockout of the Fxr gene resulted in a significantly higher degree of ANIT-induced cholestatic liver injury than that in wild-type cholestatic mice, and the amelioration of cholestasis or regulatory effects on FXR downstream genes by sarmentol H also disappeared in Fxr-/- cholestatic mice. CONCLUSION: Sarmentol H is an FXR agonist. This is the first study to show that it exerts a significant therapeutic effect on cholestatic mice, and can directly bind to FXR and activate it by recruiting the coactivator SRC1.

Herpetrione, a New Type of PPARα Ligand as a Therapeutic Strategy Against Nonalcoholic Steatohepatitis.

Non-alcoholic fatty liver disease, especially nonalcoholic steatohepatitis (NASH), is a leading cause of cirrhosis and liver cancer worldwide; nevertheless, there are no Food and Drug Administration-approved drugs for treating NASH until now. Peroxisome proliferator-activated receptor alpha (PPARα) is an interesting therapeutic target for treating metabolic disorders in the clinic, including NASH. Herpetrione, a natural lignan compound isolated from Tibetan medicine Herpetospermum caudigerum, exerts various hepatoprotective effects, but its efficacy and molecular mechanism in treating NASH have not yet been elucidated. Here, we discovered that herpetrione lessened lipid accumulation and inflammation in hepatocytes stimulated with oleic acid and lipopolysaccharide, and effectively alleviated NASH caused by a high-fat diet or methionine-choline-deficient diet by regulating glucolipid metabolism, insulin resistance, and inflammation. Mechanistically, RNA-sequencing analyses further showed that herpetrione activated PPAR signaling, which was validated by protein expression. Furthermore, the analysis of molecular interactions illustrated that herpetrione bound directly to the PPARα protein, with binding sites extending to the Arm III domain. PPARα deficiency also abrogated the protective effects of herpetrione against NASH, suggesting that herpetrione protects against hepatic steatosis and inflammation by activation of PPARα signaling, thereby alleviating NASH. Our findings shed light on the efficacy of a natural product for treating NASH, as well as the broader prospects for NASH treatment by targeting PPARα.

Salidroside alleviates acetaminophen-induced hepatotoxicity via Sirt1-mediated activation of Akt/Nrf2 pathway and suppression of NF-κB/NLRP3 inflammasome axis.

Acetaminophen (APAP) overdose-induced hepatotoxicity is the most common cause of drug-induced liver injury worldwide, which is significantly linked to oxidative stress and sterile inflammation. Salidroside is the main active component extracted from Rhodiola rosea L., with anti-oxidative and anti-inflammatory activities. Herein, we investigated the protective effects of salidroside on APAP-induced liver injury and its underlying mechanisms. Pretreatment with salidroside reversed the impacts of APAP on cell viability, LDH release, and cell apoptosis in L02 cells. Moreover, the phenomena of ROS accumulation and MMP collapse caused by APAP were reverted by salidroside. Salidroside elevated the levels of nuclear Nrf2, HO-1, and NQO1. Using PI3k/Akt inhibitor LY294002 further confirmed that salidroside mediated the Nrf2 nuclear translocation through the Akt pathway. Pretreatment with Nrf2 siRNA or LY294002 markedly prevented the anti-apoptotic effect of salidroside. Additionally, salidroside reduced the levels of nuclear NF-κB, NLRP3, ASC, cleaved caspase-1, and mature IL-1ß elevated by APAP. Moreover, salidroside pretreatment increased Sirt1 expression, whereas Sirt1 knock-down diminished the protective activities of salidroside, simultaneously reversing the up-regulation of the Akt/Nrf2 pathway and the down-regulation of NF-κB/NLRP3 inflammasome axis mediated by salidroside. We then used C57BL/6 mice to establish APAP-induced liver injury models and found that salidroside significantly alleviated liver injury. Furthermore, western blot analyses showed that salidroside promoted the Sirt1 expression, activated the Akt/Nrf2 pathway, and inhibited the NF-κB/NLRP3 inflammasome axis in APAP-treated mice. The findings of this study support a possible application of salidroside in the amelioration of APAP-induced hepatotoxicity.

Purification of biflavonoids from Selaginelladoe derleinii Hieron by special covalent organic polymers material.

Herein, a novel covalent organic polymers (COP) material based on acylhydrazone bond (AB-COP) was prepared as an efficient extraction material for enriching natural medicine biflavonoids from Selaginella doederleinii Hieron. The obtained AB-COP structure was characterized in detail. And it was the first time to investigate the effect of AB-COP on the adsorption of biflavonoids. The effects of initial concentration of solution, adsorption temperature, solid-liquid ratio, adsorption time on the adsorption of biflavonoids were studied. In addition, adsorption kinetic model, adsorption thermodynamic model and density functional theory (DFT) were also investigated to evaluate the adsorption mechanism. At the same time, the static desorption and reusability of AB-COP were investigated. Finally, the dynamic enrichment effect of AB-COP for biflavonoids was investigated. The results showed that AB-COP was successfully synthesized by Fourier transform infrared spectroscopy (FT-IR), solid state nuclear magnetism (NMR), X-ray diffraction (XRD), thermogravimetric analysis (TG), scanning electron microscopy (SEM), laser particle size analysis and Brunner Emmet Teller (BET) specific surface area test. The optimized adsorption parameters of AB-COP were initial concentration of 0.5 mg/mL, temperature of 45 °C, solid-liquid ratio of 10:10 (mg/mL), adsorption time of 60 min. The Langmuir adsorption isotherm could effectively describe the adsorption process, the pseudo-secondary adsorption model could accurately explain the adsorption mechanism, and the DFT calculations revealed that the interaction forces of AB-COP and biflavonoids were π-π stacking and hydrogen bonding. In addition, AB-COP successfully resolved biflavonoids through urea-methanol (1.3 mol/L), and the material can be reused at least four times. Finally, the solid phase extraction (SPE) chromatographic column prepared by AB-COP was successfully applied to the enrichment of biflavonoids from S. doederleinii, and the effect was significantly better than traditional chromatography materials, andthis method was also successfully applied to the enrichment of flavonoids in other plant extracts including Flos sophorae, Pericarpium viride, Lophatheri herba, Herba cuscutae. These results provide references for further purification of bioactive ingredients from plant extracts by using AB-COP.

Lignans from the seeds of Herpetospermum pedunculosum and their farnesoid X receptor-activating effect.

The seeds of Herpetospermum pedunculosum (Ser.) C.B. Clarke, a well-known Tibetan medicine in China, are rich in kinds of bioactive lignans. In this phytochemical investigation on H. pedunculosum, sixteen undescribed lignans, named as herpedulins A - P together with 24 known ones were isolated from the ethyl acetate extract of its seeds. Their structures including the absolute configurations were determined by HR MS, 1D and 2D NMR experiments, and comparison of their experimental ECD spectra with calculated ones or literature data. High content screening experiments revealed that 9 compounds could promote the expression of farnesoid X receptor in guggulsterone-induced human normal liver cells L02 cells significantly. Further molecular docking results demonstrated that herpedulin E, J and K exhibited best docking scores (9.70, 9.28 and 10.31, respectively). Hydrogen bonding and hydrophobic interactions might contribute to the main interaction of active compounds with FXR.

Dendrobine-type alkaloids from Dendrobium nobile.

Six dendrobine-type alkaloids were isolated from the tubes of Dendrobium nobile by silica gel, Sephadex LH-20 gel column chromatography, and preparative HPLC. Compound 1 is a new alkaloid containing a pair of amide tautomers, whereas compound 2 is a new dendrobine-type alkaloid. By using spectroscopic techniques including 1 D and 2 D NMR, the structures of compounds 1‒6 were identified as N-methoxylcarbonyldendrobine (1), dendronboic acid (2), dendrobine (3), 6-hydroxyldendrobine (4), dendrobine N-oxide (5), and denrine (6). The cytotoxic effects of the isolated compounds on two human tumour cell lines (HCT-116 and SW1990) were evaluated using MTT assay.

Homogenate-Ultrasound-Assisted Ionic Liquid Extraction of Total Flavonoids from Selaginella involven: Process Optimization, Composition Identification, and Antioxidant Activity.

In this paper, an efficient approach to extract total flavonoids (TFs) from Selaginella involvens (Sw.) Spring using homogenate-ultrasound-assisted ionic liquid (IL) extraction (HUA-ILE) was first developed. The results indicated that EPyBF4 was selected as the suitable extractant. According to the single factor experiment and response surface methodology, the IL concentration of 0.10 mol/L, the extraction time of 160 s, the liquid/solid ratio of 13:1 mL/g, and the extraction power of 300 W were concluded as the best conditions. A yield of 8.48 ± 0.27 mg/g TF content was obtained. Compared with HUA ethanol extraction, ultrasound-assisted IL extraction, and percolation extraction, the TF content obtained by the HUA-ILE method could be increased by 2 to 4 times, and the extraction time could be reduced by 100 times. Furthermore, 16 compounds of the TF extract were finally identified through ultra-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry, among which 11 compounds were first discovered in S. involven. The contents of six biflavonoids in S. involven were determined simultaneously adopting high-performance liquid chromatography, including amentoflavone, hinokiflavone, bilobetin, ginkgetin, isoginkgetin, and heveaflavone. The TF extract in S. involven was proved to have potent antioxidant activity through the four antioxidant experiments. In conclusion, HUA-ILE was applied for the first time to exploit a green, efficient, and novel approach to extract TFs, and the research also provided promising prospects for applications of S. involven.

Dihydrophenanthrofurans and bisbibenzyl derivatives from the stems of Dendrobium nobile.

Two new dihydrophenanthrofurans (1 and 2) and two new bisbibenzyl derivatives (3 and 4) were isolated from the traditional Chinese medicinal plant Dendrobium nobile, along with four known compounds (5-8). The absolute configurations of compounds 1 and 4 were elucidated through extensive NMR and ECD spectroscopic analyses. New compounds showed no antimicrobial activity against four gram-positive bacterial strains and four gram-negative bacteria at the concentration of 1 mg/mL, but displayed significant cytotoxic activity against HepG2 human hepatic cell line with the IC50 values ranging from 1.25 µM to 19.47 µM.

Mirabijalone E: a novel rotenoid from Mirabilis himalaica inhibited A549 cell growth in vitro and in vivo.

ETHNOPHARMACOLOGICAL RELEVANCE: The roots of Mirabilis himalaica have been used in Tibetan folk medicine for treatment of uterine cancer, nephritis edematous, renal calculus and arthrodynia. In our previous work, the ethanol extract of roots had shown potent cytotoxicity against human cancer cells. However, no information is available on the antitumor effect of Mirabilis himalaica. The aim of the present study was to investigate the active constituents guided by bioassay and evaluate the related antitumor efficacy in vitro and in vivo. MATERIALS AND METHODS: The active subextract (ethyl acetate) was subjected to successive chemical separation using a combination of silica gel, LH-20 chromatography and semi-preparative HPLC. The structures were determined by spectroscopic analysis techniques such as nuclear magnetic resonance (NMR) and mass spectrometry. Three human cancer cell lines, A549, HepG2 and HeLa were used for in vitro cytotoxicity evaluation of all isolated compounds by MTT-assay. Then, the potent and novel compound mirabijalone E was employed to the mechanism study againstA549 cells. BrdU immunofluorescence, soft agar assay and cell cycle analysis were employed to detect the cell proliferation effects. Annexin V-FITC/PI staining assay was used for examining apoptotic effects. Expression levels of apoptosis-related proteins were determined by western blot assay. in vivo tumorigenic assay was used to evaluate the xenograft tumor growth treated with mirabijalone E. RESULTS: One new rotenoid compound, mirabijalone E, together with eight known rotenoids was isolated from Mirabilis himalaica. Mirabijalone E, 9-O-methyl-inone B, boeravinone C and boeravinone H exhibited cytotoxicity against A 549 and HeLa cells. Further study on mirabijalone E was carried out in vitro and in vivo. Mirabijalone E inhibited A549 cells growth in a time and dose-dependent manner, which arrested cell cycle in S phase. Mechanistically, mirabijalone E treatment resulted in the increase of Bax expression level, the decrease of Bcl-2 level and the activation of caspase-3, which suggested the activation of apoptosis cascades. Consequently, the xenograft treated with mirabijalone E showed markedly suppressed tumor growth. CONCLUSIONS: The result suggested that mirabijalone E, together with active compounds, 9-O-methyl-4-hydroxyboeravinone B, boeravinone C and boeravinone H could be a promising candidate for cancer therapy.