Fraxin Prevents Chemically Induced Hepatotoxicity by Reducing Oxidative Stress

Acer tegmentosum Maxim and Bacillus subtilis-fermented products inhibit TNF-α-induced endothelial inflammation and vascular dysfunction of the retina: the role of tyrosol moiety in active compounds targeting Glu230 in SIRT1

Acer tegmentosum Maxim (AT) is a medicinal plant used to treat hepatic, neurological diseases, and cancer. However, the beneficial effects of AT on endothelial dysfunction have not been reported yet. In this study, we evaluated the effects of AT and the main compounds against TNF-α-mediated inflammatory responses and their possible mechanism of action. The anti-inflammatory effect and its molecular mechanism were analyzed by adhesion assay, immunoblotting, promoter-luciferase assay, ELISA, RT-PCR, immunocytochemistry, immunoprecipitation, siRNA gene knockdown, docking, and molecular dynamics simulation. AT and its compounds salidroside and tyrosol reduced TNF-α-induced adhesion between monocytes and endothelial cells. Fermentation of AT with Bacillus subtilis converted salidroside to tyrosol, which is salidroside's aglycone. The fermented AT product (ATF) potently inhibited TNF-α-mediated monocyte adhesion with higher potency than AT. AT or ATF abrogated TNF-α-induced expression of adhesion molecules (VCAM-1 and ICAM-1) and production of MCP-1 with the inhibition of phosphorylated MAP kinases. TNF-α-mediated NF-κB transactivation and RelA/p65 acetylation were suppressed by AT and ATF through the interaction of NF-κB with sirtuin-1 (SIRT1), an NAD+-dependent histone deacetylase. Sirt1 gene knockdown diminished the protective effects of AT and ATF against TNF-α-mediated signaling and inflammatory response. Interestingly, SIRT1 protein expression was significantly increased by ATF and tyrosol rather than by AT and salidroside, respectively. Molecular docking showed that the tyrosol moiety is critical for the interaction with Glu230 of SIRT1 (PDB ID: 4ZZH and 4ZZJ) for the deacetylase activity. Molecular dynamics revealed that tyrosol can induce the movement of the N-terminal domain toward the catalytic domain of SIRT1. This study demonstrates the potential of AT and ATF to prevent endothelial inflammation and vascular dysfunction of the retina by the MAPK/NF-κB/SIRT1 signaling pathways and targeting of the tyrosol moiety to Glu230 in SIRT1.

Plant-Derived Coumarins: A Narrative Review of Their Structural and Biomedical Diversity

Plant-derived coumarin (PDC) is a naturally occurring heterocyclic backbone that belongs to the benzopyrone family. PDC and its based products are characterized by low toxicity and high distribution in a variety of herbal treatments that have numerous therapeutic potentials. These include anticoagulants, antibacterials, anti-inflammatory agents, anticancer agents, antioxidants, and others. So, it may be appropriate to investigate the qualities and potential bioactivities of PDCs. This article provides an overview of the biomedical potentials, availability, and clinical use possibilities of PDCs, with a focus on their important modes of action, using information on various pharmacological qualities discovered. The data used in this study came from published research between 2015 and 2023. We reviewed a selection of databases, including PubMed, Scopus, Web of Science, and Google Scholar, during that period. In conclusion, because of their abundance in medicinal plants, the clinical biochemistry attributes of PDCs are currently of interest. In a variety of medical specialties, PDCs serve a useful role as therapeutic agents.

Anti-cytokine Storm Activity of Fraxin, Quercetin, and their Combination on Lipopolysaccharide-Induced Cytokine Storm in Mice: Implications in COVID-19

Background

Cytokine release syndrome (CRS) is the leading cause of mortality in advanced stages of coronavirus patients. This study examined the prophylactic effects of fraxin, quercetin, and a combination of fraxin+quercetin (FQ) on lipopolysaccharide-induced mice.

Methods

Sixty mice were divided into six groups (n=10) as follows: control, LPS only, fraxin (120 mg/Kg), quercetin (100 mg/Kg), dexamethasone (5 mg/Kg), and FQ. All treatments were administered intraperitoneally (IP) one hour before induction by LPS (5 mg/Kg) IP injection. Twenty-four hours later, the mice were euthanized. Interleukin one beta (IL-1β), interleukin 6 (IL-6), and tumor necrosis factor-alpha (TNF-α) were quantified using an enzyme-linked immunosorbent assay (ELISA), and lung and kidney tissues were examined for histopathological alterations. This study was conducted at Al-Nahrain University, Baghdad, Iraq, in 2022.

Results

FQ reduced IL-1β (P<0.001). All treatments significantly suppressed IL-6, fraxin, quercetin, dexamethasone, and FQ, all with P<0.001. The TNF-α level was reduced more with dexamethasone (P<0.001) and quercetin (P<0.001). Histopathological scores were significantly reduced mainly by quercetin and FQ in the lungs with scores of 12.30±0.20 (P=0.093), and 15.70±0.20 (P=0.531), respectively. The scores were 13±0.26 (P=0.074) and 15±0.26 (P=0.222) for quercetin and FQ in the kidneys, respectively.

Conclusion

All used treatments reduced proinflammatory cytokine levels and protected against LPS-induced tissue damage.

Fraxin inhibits melanogenesis by suppressing the ERK/MAPK pathway and antagonizes oxidative stress by activating the NRF2 pathway

Hyperpigmentation disorders, such as melasma and freckles, are highly prevalent and draw increasing attention. Patients thus tend to seek effective and safe cosmetic whitening agents. Fraxin, a bioactive substance extracted from Cortex Fraxini, possesses anti-inflammation and antioxidant properties. In this study, we further explored the anti-melanogenic activities of fraxin were explored in vitro and in vivo. We found that pretreatment with fraxin decreased the melanin content of MNT1 cells and zebrafishes. In MNT1 cells, melanogenesis-related proteins, such as MITF, TYR, TYRP1, and DCT were down-regulated and tyrosinase activity was reduced under fraxin treatment. Further exploration of the mechanism revealed that fraxin could inhibit the phosphorylation of ERK, which is closely related to melanogenesis. Besides, fraxin also protected MNT1 cells from H2O2-induced apoptosis via scavenging reactive oxygen species (ROS) in cells. Further experimentation revealed that fraxin could activate NRF2 and upregulate antioxidase CAT and HO-1. In conclusion, fraxin could be an effective agent with anti-melanogenesis and antioxidant properties for hyperpigmentation disorders.

A newly identified small tRNA fragment reveals the regulation of different wool types and oxidative stress in lambs

Novel small RNAs derived from tRNAs are continuously identified, however, their biological functions are rarely reported. Here, we accidentally found the reads peak at 32nt during statistical analysis on the miRNA-seq data of lamb skin tissue, and found that it was related to the wool type of lambs. This 32nt peak was composed of small tRNA fragments. The main component sequence of this peak was a novel small tRNA derived from Glycyl tRNA (tRNAGly), the expression level of tRNAGly-derived tRNA fragments (tRFGly) was 5.77 folds higher in the coarse wool lambs than that in the fine wool lambs. However, in contrast, the expression of tRNAGly in the skin of fine wool lambs is 6.28 folds more than that in coarse wool lambs. tRNAGly promoted the synthesis of high glycine protein including KAP6 in fine wool lamb skin. These proteins were reported as the major genes for fine curly wool. Integrative analysis of target gene prediction, proteomics and metabolomics results revealed that tRFGly reduced the level of reactive oxygen species (ROS) in the skin of coarse wool lambs by targeted inhibition of the Metabolic signal and the corresponding Glutathione metabolic pathway, on the contrary, the level of oxidative stress in the skin of fine wool lambs was significantly higher. This study revealed for the first time the relationship between tRNAGly and its derived tRFGly and animal traits. tRFGly has the function of targeting and regulating protein synthesis. At the same time, tRFGly can reduce the expression of its resource complete tRNA, thereby reducing its ability to transport specific amino acid and affecting the expression of corresponding proteins.

Gomphrena globosa L. extract alleviates carbon tetrachoride-induced liver injury in mice by activating antioxidant signaling pathways and promoting autophagy

BACKGROUND

Carbon tetrachloride (CCl₄) is highly toxic to animal liver and is a major contributor to liver injury. Gomphrena globosa L. (GgL) is an edible plant with anti-inflammation and antioxidation properties. The aim of this study was to investigate the potential therapeutic effects of GgL on liver injury.

METHODS AND RESULTS

A model of chronic liver injury in mice was established by intraperitoneal injection of CCl₄ (0.4 mL/kg) for 3 weeks, and the mice were treated intraperitoneally with different concentrations of GgL crude extract (GgCE; 100, 200, 300 mg/kg) or Bifendatatum (Bif; 20 mg/kg) in the last 2 weeks. The results showed that GgCE treatment alleviated the liver injury, improved the pathological changes caused by CCl₄ on the mice liver, and enhance the antioxidant capacity. We also found that GgCE increased the expression of antioxidant stress related proteins, decreased the phosphorylation levels of autophagy related proteins PI3K and mTOR, and decreased the expression of LC3 II and P62 proteins.

CONCLUSION

These results suggest that GgCE alleviated CCl₄-induced chronic liver injury in mice by activating antioxidant signaling pathways and promoting autophagy, indicating a potential therapeutic effect of GgCE on liver injury.

Dietary phenolic-type Nrf2-activators: implications in the control of toxin-induced hepatic disorders

Numerous studies have exemplified the importance of nuclear factor erythroid 2-related factor 2 (Nrf2) activation in the alleviation of toxin-induced hepatic disorders primarily through eliminating oxidative stress. Whereafter, increasingly more efforts have been contributed to finding Nrf2-activators, especially from dietary polyphenols. The present review summarized the phenolic-type Nrf2-activators published in the past few decades, analyzed their effectiveness based on their structural characteristics and outlined their related mechanisms. It turns out that flavonoids are the largest group of phenolic-type Nrf2-activators, followed by nonflavonoids and phenolic acids. When counting on subgroups, the top three types are flavonols, flavones, and hydroxycinnamic acids, with curcuminoids having the highest effective doses. Moreover, most polyphenols work through the phosphorylation of Nrf2. Besides, mitogen-activated protein kinases (MAPKs) and protein kinase B (Akt) are the frequent targets of these Nrf2-activators, which indirectly mediate the behavior of Nrf2. However, current data are not sufficient to conclude any structure-activity relationship.

Comparative Metabolomics of Reproductive Organs in the Genus Aesculus (Sapindaceae) Reveals That Immature Fruits Are a Key Organ of Procyanidin Accumulation and Bioactivity

Fruit from A. hippocastanum L. are used commercially for chronic venous insufficiency (CVI). The isomeric mixture of pentacyclic triterpenoid saponins (β-aescin) exert anti-inflammatory effects. Hence, research has focused on β-aescin, yet the diversity, accumulation, and bioactivity of organ-specific secondary metabolites represent missed pharmacological opportunities. To this end, we applied an untargeted metabolomics approach by liquid chromatography-tandem mass spectrometry (LC-MS/MS) to the chemical profiles of flowers, immature fruits, and pedicels from 40 specimens across 18 species of Aesculus. Principal component analysis (PCA), orthogonal partial least squares (OPLS-DA), and molecular networking revealed stronger chemical differences between plant organs, than between species. Flowers are rich in glycosylated flavonoids, pedicels in organic acids and flavonoid aglycones, and immature fruits in monomeric flavan-3-ols and procyanidins. Although a high diversity of flavonoids and procyanidins was observed, the relative amounts differed by plant organ. Fruit extracts demonstrated the strongest antifungal (Saccharomyces cerevisiae) and antioxidant activity, likely from the procyanidins. Overall, secondary metabolite profiles are organ-specific, and fruits accumulate antifungal and antioxidant compounds. Due to the chemical similarity between species, similar effects may be achieved between species. This creates incentives for further exploration of the entire genus, in bioprospecting for potential therapeutic leads.

Potential Effects of Dietary Isoflavones on Drug-Induced Liver Injury

Numerous prescribed drugs and herbal and dietary supplements have been reported to cause drug-induced acute liver injury, which is a frequent cause of acute liver failure (ALF). It is a tremendous challenge with ever-increasing drug application in the medication system for huge populations. Drug-induced acute liver injury can lead to diverse pathologies similar to acute and chronic hepatitis, acute liver failure, biliary obstruction, fatty liver disease, and so on. Recently, extensive work demonstrated that isoflavones play an essential and protecting role in drug-induced liver injury (DILI). The isoflavones mediated hepatoprotection by modulating specific genes linked with control of cellular redox homeostasis and inflammatory responses. Isoflavones upregulate oxidative stress-responsive nuclear factor erythroid 2-like 2 (Nrf2), downregulate inflammatory nuclear factor-κB (NF-κB) signaling pathways, and modulate a balance between cell survival and death. Moreover, isoflavones actively inhibit the expression of cytochromes P450 (CYPs) enzyme during drug metabolism. Moreover, isoflavones are also linked with farnesoid X receptor (FXR) activation and signal transducer and activator of transcription factor 3 (STAT3) phosphorylation in hepatoprotection DILI. In vivo and in vitro studies clearly stated that isoflavones bear strong antioxidant potential and promising agents for hepatotoxicity prevention and stressed their potential role as therapeutic supplements in DILI. The current review will elaborate on isoflavones’ preventive and therapeutic potential concisely and highlight various molecular targets to exert a protective effect on DILI.

Identification of anti-inflammatory compounds from Zhongjing formulae by knowledge mining and high-content screening in a zebrafish model of inflammatory bowel diseases

BACKGROUND

Inflammatory bowel diseases (IBD) are chronic relapsing intestinal inflammations with increasing global incidence, and new drug development remains in urgent demand for IBD management. To identify effective traditional Chinese medicine (TCM) formulae and compounds in IBD treatment, we innovatively combined the techniques of knowledge mining, high-content screening and high-resolution mass spectrometry, to conduct a systematic screening in Zhongjing formulae, which is a large collection of TCM prescriptions with most abundant clinical evidences.

METHODS

Using Word2vec-based text learning, the correlations between 248 Zhongjing formulae and IBD typical symptoms were analyzed. Next, from the top three formulae with predicted relationship with IBD, TCM fractions were prepared and screened on a transgenic zebrafish IBD model for their therapeutic effects. Subsequently, the chemical compositions of the fraction hits were analyzed by mass spectrometry, and the major compounds were further studied for their anti-IBD effects and potential mechanisms.

RESULTS

Through knowledge mining, Peach Blossom Decoction, Pulsatilla Decoction, and Gegen Qinlian Decoction were predicted to be the three Zhongjing formulae mostly related to symptoms typical of IBD. Seventy-four fractions were prepared from the three formulae and screened in TNBS-induced zebrafish IBD model by high-content analysis, with the inhibition on the intestinal neutrophil accumulation and ROS level quantified as the screening criteria. Six herbal fractions showed significant effects on both pathological processes, which were subsequently analyzed by mass spectrometry to determine their chemical composition. Based on the major compounds identified by mass spectrometry, a second-round screen was conducted and six compounds (palmatine, daidzin, oroxyloside, chlorogenic acid, baicalin, aesculin) showed strong inhibitory effects on the intestinal inflammation phenotypes. The expression of multiple inflammatory factors, including il1β, clcx8a, mmp and tnfα, were increased in TNBS-treated fish, which were variously inhibited by the compounds, with aesculin showing the most potent effects. Moreover, aesculin and daidzin also upregulated e-cadherin's expression.

CONCLUSION

Taken together, we demonstrated the regulatory effects of several TCM formulae and their active compounds in the treatment of IBD, through a highly efficient research strategy, which can be applied in the discovery of effective TCM formulae and components in other diseases.

Is natural fraxin an overlooked radical scavenger?

Fraxin (FX) (7-hydroxy-6-methoxycoumarin 8-glucoside) is a typical natural product of the coumarin family. This compound was shown to protect endothelial cells from oxidative stress; however, the nature of its antioxidant properties is still ambiguous. In this study, we report on a systematic evaluation of the radical scavenging activity of FX using a two-tier protocol based on thermodynamic and kinetic calculations. The results show that FX has moderate activity in the aqueous physiological environment against a range of radicals including HO˙, CCl3O˙, CCl3OO˙, NO2, , and HOO˙. The latter was examined in detail due to the prevalence of HOO˙ as a source of oxidative stress in biological systems. HOO˙ scavenging activity was promising in the gas phase but low in physiological environments with k overall = 1.57 × 106, 3.13 × 102 and 2.68 × 103 M-1 s-1 in the gas phase, pentyl ethanoate and water solvents, respectively. The formal hydrogen transfer mechanism at the O7-H bond dominates the hydroperoxyl radical scavenging of FX in the nonpolar media, whereas, in the polar environment, the activity is exerted by the single electron transfer mechanism of the anion state. This activity falls behind typical antioxidants such as Trolox, ascorbic acid, and trans-resveratrol under the studied conditions. Thus FX may have multiple health benefits, but it is not an outstanding natural antioxidant.

Regulation of Nrf2/ARE Pathway by Dietary Flavonoids: A Friend or Foe for Cancer Management?

The nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant response element (ARE) pathway is an important cell signaling mechanism in maintaining redox homeostasis in humans. The role of dietary flavonoids in activating Nrf2/ARE in relation to cancer chemoprevention or cancer promotion is not well established. Here we summarize the dual effects of flavonoids in cancer chemoprevention and cancer promotion with respect to the regulation of the Nrf2/ARE pathway, while underlying the possible cellular mechanisms. Luteolin, apigenin, quercetin, myricetin, rutin, naringenin, epicatechin, and genistein activate the Nrf2/ARE pathway in both normal and cancer cells. The hormetic effect of flavonoids has been observed due to their antioxidant or prooxidant activity, depending on the concentrations. Reported in vitro and in vivo investigations suggest that the activation of the Nrf2/ARE pathway by either endogenous or exogenous stimuli under normal physiological conditions contributes to redox homeostasis, which may provide a mechanism for cancer chemoprevention. However, some flavonoids, such as luteolin, apigenin, myricetin, quercetin, naringenin, epicatechin, genistein, and daidzein, at low concentrations (1.5 to 20 µM) facilitate cancer cell growth and proliferation in vitro. Paradoxically, some flavonoids, including luteolin, apigenin, and chrysin, inhibit the Nrf2/ARE pathway in vitro. Therefore, even though flavonoids play a major role in cancer chemoprevention, due to their possible inducement of cancer cell growth, the effects of dietary flavonoids on cancer pathophysiology in patients or appropriate experimental animal models should be investigated systematically.

Coumarins as Modulators of the Keap1/Nrf2/ARE Signaling Pathway

The Keap1/Nrf2/ARE system is a central defensive mechanism against oxidative stress which plays a key role in the pathogenesis and progression of many diseases. Nrf2 is a redox-sensitive transcription factor controlling a variety of downstream antioxidant and cytodefensive genes. Nrf2 has a powerful anti-inflammatory activity mediated via modulating NF-κB. Therefore, pharmacological activation of Nrf2 is a promising therapeutic strategy for the treatment/prevention of several diseases that are underlined by both oxidative stress and inflammation. Coumarins are natural products with promising pharmacological activities, including antioxidant, anticancer, antimicrobial, and anti-inflammatory efficacies. Coumarins are found in many plants, fungi, and bacteria and have been widely used as complementary and alternative medicines. Some coumarins have shown an ability to activate Nrf2 signaling in different cells and animal models. The present review compiles the research findings of seventeen coumarin derivatives of plant origin (imperatorin, visnagin, urolithin B, urolithin A, scopoletin, esculin, esculetin, umbelliferone, fraxetin, fraxin, daphnetin, anomalin, wedelolactone, glycycoumarin, osthole, hydrangenol, and isoimperatorin) as antioxidant and anti-inflammatory agents, emphasizing the role of Nrf2 activation in their pharmacological activities. Additionally, molecular docking simulations were utilized to investigate the potential binding mode of these coumarins with Keap1 as a strategy to disrupt Keap1/Nrf2 protein-protein interaction and activate Nrf2 signaling.

Fraxin Alleviates LPS-Induced ARDS by Downregulating Inflammatory Responses and Oxidative Damages and Reducing Pulmonary Vascular Permeability

Acute respiratory distress syndrome (ARDS) is a severe acute disease that threatens human health, and few drugs that can effectively treat this disease are available. Fraxin, one of the main active ingredients of Cortex Fraxini, a Chinese herbal medicine, has presented various pharmacological and biological activities. However, the effects of fraxin on ARDS have yet to be reported. In the present study, the protective effect of fraxin in lipopolysaccharide (LPS)-induced ARDS in a mouse model was analyzed. Results from the hematoxylin and eosin staining showed that fraxin might alleviate pathological changes in the lung tissues of mice with ARDS. ELISA and Western blot results revealed that fraxin might inhibit the production of inflammatory factors, namely, IL-6, TNF-α, and IL-1β, and the activation of NF-κB and MAPK signaling pathways in the lungs. Thus, the inflammatory responses were reduced. Fraxin might inhibit the increase in reactive oxygen species (ROS) and malondialdehyde (MDA), a product of lipid peroxidation in lung tissues. Fraxin might increase the superoxide dismutase (SOD) activity to avoid oxidative damage. Vascular permeability was also assessed through Evans blue dye tissue extravasation and fluorescein isothiocyanate-labeled albumin (FITC-albumin) leakage. Fraxin might inhibit the increase in pulmonary vascular permeability and relieve pulmonary edema. Fraxin was also related to the inhibition of the increase in matrix metalloproteinase-9, which is a glycocalyx-degrading enzyme, and the relief of damages to the endothelial glycocalyx. Thus, fraxin elicited protective effects on mice with LPS-induced ARDS and might be used as a drug to cure ARDS induced by Gram-negative bacterial infection.

Preventive effects of fraxin on ischemia/reperfusion-induced acute kidney injury in rats

AIM

Kidney ischemia reperfusion (IR) injury is an important health problem resulting in acute kidney failure. The oxidative stress and inflammatory process are the underlying mechanisms of IR injury. It has been purposed in this study to research the possible protective effects of fraxin on kidney injury induced by IR.

MATERIAL AND METHODS

32 Sprague Dawley male rats were divided into 4 groups. The groups were organized as follows; sham, IR, IR + fraxin 10 mg/kg, and IR + 50 mg/kg fraxin groups. Some oxidant, antioxidant and inflammatory parameters were evaluated in kidney tissues removed at the end of our experimental study.

KEY FINDINGS

It was detected that the oxidant and proinflammatory markers increased and antioxidant parameters decreased in IR group but the results significantly reversed in treatment groups compared to IR group. And also, 8-OHdG, NF-κB, HAVCR1 immunopositivities were at severe levels and these results attenuated in IR fraxin + 10 mg/kg, and IR + fraxin 50 mg/kg groups.

SIGNIFICANCE

These presented results have shown that fraxin performed protective effects against kidney injury induced by IR.

Suppression of 6-Hydroxydopamine-Induced Oxidative Stress by Hyperoside Via Activation of Nrf2/HO-1 Signaling in Dopaminergic Neurons

In our ongoing research to discover natural products with neuroprotective effects, hyperoside (quercetin 3-O-galactoside) was isolated from Acer tegmentosum, which has been used in Korean traditional medicine to treat liver-related disorders. Here, we demonstrated that hyperoside protects cultured dopaminergic neurons from death via reactive oxygen species (ROS)-dependent mechanisms, although other relevant mechanisms of hyperoside activity remain largely uncharacterized. For the first time, we investigated the neuroprotective effects of hyperoside on 6-hydroxydopamine (6-OHDA)-induced neurotoxicity in neurons, and the possible underlying mechanisms. Hyperoside significantly ameliorated the loss of neuronal cell viability, lactate dehydrogenase release, excessive ROS accumulation and mitochondrial membrane potential dysfunction associated with 6-OHDA-induced neurotoxicity. Furthermore, hyperoside treatment activated the nuclear erythroid 2-related factor 2 (Nrf2), an upstream molecule of heme oxygenase-1 (HO-1). Hyperoside also induced the expression of HO-1, an antioxidant response gene. Remarkably, we found that the neuroprotective effects of hyperoside were weakened by an Nrf2 small interfering RNA, which blocked the ability of hyperoside to inhibit neuronal death, indicating the vital role of HO-1. Overall, we show that hyperoside, via the induction of Nrf2-dependent HO-1 activation, suppresses neuronal death caused by 6-OHDA-induced oxidative stress. Moreover, Nrf2-dependent HO-1 signaling activation represents a potential preventive and therapeutic target in Parkinson's disease management.

Simultaneous Determination of Eight Active Compounds in Baitouweng Decotion and its Single Herbs

Baitouweng Decotion (BD) is a famous traditional Chinese medicinal prescription, which is composed of Pulsatilla chinensis (bunge) regel, Coptis chinensis franch., Phellodendron chinense and Cortex Fraxini. In this study, a simple and sensitive high performance liquid chromatography coupled with ultraviolet detection method was established for the simultaneous determination of eight marker compounds including Esculin, Fraxin, Esculetin, Fraxetin, Columbamine, Coptisine, Palmatine Chloride and Berberine hydrochloride in BD, the single herbs and their negative controls. The chromatographic separation was performed using an Agilent Eclipse XDB-C18 column with a gradient elution system of acetonitrile and 0.1% phosphoric acid (contained 0.2% triethylamine) solution at a flow rate of 0.8 mL/min. The results demonstrated that the validated method was simple, reliable and successfully applied to evaluate the selected compounds in water extraction (BDW) and ethanol extraction (BDE) of BD, the single herbs and their negative control for quality control. Moreover, the experimental data showed that the contents of the major active components detected in BDE were significantly higher than those in the BDW, while the BDW had several peaks BDE without. The paper also suggested a method to extract Fraxin, Esculin, Fraxetin, Esculetin and Berberine from Baitouweng Decotion more effectively.

Fraxin inhibits lipopolysaccharide-induced inflammatory cytokines and protects against endotoxic shock in mice

Fraxin, the effective component isolated from Cortex Fraxini, has been reported to have anti-inflammation effects. The aim of this study was to explore the effect of fraxin on lipopolysaccharide (LPS)-induced endotoxic shock in mice. We used Kunming male mice to establish the model, and we found that fraxin could improve the survival rate of the LPS-induced mice. Histopathological study showed that fraxin could mitigate the injuries in LPS-induced lung and liver tissues. The levels of tumour necrosis factor-α and interleukin-6 both in serum and lung, liver tissues, and the productions of nitric oxide (NO), aspartate transaminase and alanine transaminase in serum were decreased by fraxin. Western blot assay demonstrated that the pretreatment with fraxin could downregulate LPS-induced protein expressions of nuclear factor-kappa B (NF-κB) and NLRP3 inflammatory corpuscle signalling pathways. Overall, fraxin had protective effects on LPS-induced endotoxic shock mice and the possible mechanisms might activate through NF-κB and NLRP3 inflammatory corpuscle signalling pathways.

Hepatoprotective effects of an Acer tegmentosum Maxim extract through antioxidant activity and the regulation of autophagy

ETHNOPHARMACOLOGICAL RELEVANCE

Acer tegmentosum Maxim (AT), the East Asian stripe maple, is an herb used to treat liver disease and is approved as a functional food in Korea. AT protects against hepatic disorders, atopic dermatitis, and diabetes mellitus.

AIM OF THE STUDY

We explored the mechanism of the hepatoprotective effects of AT extract in in vitro and in vivo levels.

MATERIALS AND METHODS

AT extract from Acer tegmentosum Maxim was extracted by hot water. Hepatoprotective effects of AT extract were confirmed using carbon tetrachloride (CCl₄)- or alcohol-induced mouse model, and H₂O₂- or alcohol-induced HepG2 (liver hepatocellular carcinoma cell line) cells by measuring GOT, GPT, TG, and MDA levels. Hematoxylin and eosin (H&E) staining was used to observe the pathological analysis. Cytotoxicity or protective effect of AT extract was confirmed using MTT assay in HepG2 cells. Antioxidant effect of AT extract was measured using DPPH or H₂DCFDA assay. Mechanism study of antioxidant and autophagy was carried out using western blotting and immunofluorescence analysis.

RESULTS

AT extract increased the viability of HepG2 cells treated with H₂O₂ and ethanol, and protected the liver against damage induced by CCl₄ and alcohol. The AT extract increased the levels of nuclear respiratory factor 2 (Nrf2) and heme oxygenase-1 (HO-1). The level of microtubule-associated protein light chain 3 (LC3)-Ⅱ, beclin-1, autophagy-related genes (Atg) such as Atg3 and Atg12-5 as markers of autophagy activation was also increased. Moreover, the AT extract increased activation of mitogen-activated protein kinase (MAPK), which regulated autophagy and HO-1.

CONCLUSION

Therefore, these results indicate that the AT extract has a hepatoprotective effect by increasing antioxidant activity and inducing autophagy.

Isoamericanoic Acid B from Acer tegmentosum as a Potential Phytoestrogen

Phytoestrogens derived from plants have attracted the attention of the general public and the medical community due to their potentially beneficial role in relieving menopausal symptoms. The deciduous tree Acer tegmentosum Maxim (Aceraceae) has long been utilized in Korean folk medicine to alleviate many physiological disorders, including abscesses, surgical bleeding, and liver diseases. In order to explore structurally and/or biologically new constituents from Korean medicinal plants, a comprehensive phytochemical study was carried out on the bark of A. tegmentosum. One new phenolic compound with a 1,4-benzodioxane scaffold, isoamericanoic acid B (1), as well as with nine known phenolic compounds (2–10), were successfully isolated from the aqueous extracts of the bark of A. tegmentosum. A detailed analysis using 1D and 2D NMR spectroscopy, electronic circular dichroism (ECD) spectral data, and LC/MS afforded the unambiguous structural determination of all isolated compounds, including the new compound 1. In addition, compounds 2, 4, 5, and 9 were isolated and identified from the bark of A. tegmentosum for the first time. All isolated compounds were tested for their estrogenic activities using an MCF-7 BUS cell proliferation assay, which revealed that compounds 1, 2, and 10 showed moderate estrogenic activity. To study the mechanism of this estrogenic effect, a docking simulation of compound 1, which showed the best estrogenic activity, was conducted with estrogen receptor (ER) -α and ER-β, which revealed that it interacts with the key residues of ER-α and ER-β. In addition, compound 1 had slightly higher affinity for ER-β than ER-α in the calculated Gibbs free energy for 1:ER-α and 1:ER-β. Thus, the present experimental evidence demonstrated that active compound 1 from A. tegmentosum could be a promising phytoestrogen for the development of natural estrogen supplements.

Oxaloacetate Ameliorates Chemical Liver Injury via Oxidative Stress Reduction and Enhancement of Bioenergetic Fluxes

Chemical injury is partly due to free radical lipid peroxidation, which can induce oxidative stress and produce a large number of reactive oxygen species (ROS). Oxaloacetic acid is an important intermediary in the tricarboxylic acid cycle (TCA cycle) and participates in metabolism and energy production. In our study, we found that oxaloacetate (OA) effectively alleviated liver injury which was induced by hydrogen peroxide (H₂O₂) in vitro and carbon tetrachloride (CCl₄) in vivo. OA scavenged ROS, prevented oxidative damage and maintained the normal structure of mitochondria. We further confirmed that OA increased adenosine triphosphate (ATP) by promoting the TCA production cycle and oxidative phosphorylation (OXPHOS). Finally, OA inhibited the mitogen-activated protein kinase (MAPK) and apoptotic pathways by suppressing tumor necrosis factor-α (TNF-α). Our findings reveal a mechanism for OA ameliorating chemical liver injury and suggest a possible implementation for preventing the chemical liver injury.