Dendrobium nobile Lindl. alkaloids-mediated protection against CCl4-induced liver mitochondrial oxidative damage is dependent on the activation of Nrf2 signaling pathway

Research progress on the regulatory and pharmacological mechanism of chemical components of Dendrobium

Dendrobium is a precious Chinese herbal medicine, which belongs to the genus Orchidaceae. Ancient records and modern pharmacological research show that Dendrobium has pharmacological effects such as anti-tumor, antioxidant regulating immunity and blood glucose, and anti-aging. Dendrobium contains polysaccharides, alkaloids, bibenzyl, sesquiterpenes, phenanthrene, polyphenols and other types of chemicals. Its pharmacological activity is closely related to these chemical components. For example, dendrobium extracts can achieve anti-tumor effects by inhibiting tumor cell proliferation and metastasis, promoting cell apoptosis and ferroptosis, or increasing cell sensitivity to chemotherapy drugs. It enhances immunity by regulating immune cell activity or cytokine release. In addition, it can alleviate neurodegenerative diseases by protecting nerve cells from apoptotic damage. In recent years, research reports on biologically active compounds in Dendrobium have shown a blowout growth, which makes us realize that it is meaningful to continuously update the research progress on the components and pharmacological regulatory mechanism of this traditional Chinese medicine. By classifying the collected chemical components according to different chemical structures and summarizing their pharmacological mechanisms, we investigated the current research progress of Dendrobium and provide a more comprehensive scientific foundation for the further development and clinical transformation of Dendrobium in the future.

Inhibition of mitochondrial ROS-mediated necroptosis by Dendrobium nobile Lindl. alkaloids in carbon tetrachloride induced acute liver injury

ETHNOPHARMACOLOGICAL RELEVANCE

Dendrobium nobile Lindl. (DNL) is a well-known traditional Chinese medicine that has been recorded in the Chinese Pharmacopoeia (2020 edition). The previous data showed that Dendrobium nobile Lindl. alkaloids (DNLA) protect against CCl4-induced liver damage via oxidative stress reduction and mitochondrial function improvement, yet the exact regulatory signaling pathways remain undefined.

AIM OF THE STUDY

The aim of the present study was to investigate the role of necroptosis in the mode of CCl4-induced liver injury and determine whether DNLA protects against CCl4-induced acute liver injury (ALI) by inhibiting mitochondrial ROS (mtROS)-mediated necroptosis.

MATERIALS AND METHODS

DNLA was extracted from DNL, and the content was determined using liquid chromatograph mass spectrometer (LC-MS). In vivo experiments were conducted in C57BL/6J mice. Animals were administrated with DNLA (20 mg/kg/day, ig) for 7 days, and then challenged with CCl4 (20 μL/kg, ip). CCl4-induced liver injury in mice was evaluated through the assessment of biochemical indicators in mouse serum and histopathological examination of hepatic tissue using hematoxylin and eosin (H&E) staining. The protein and gene expressions were determined with western blotting and quantitative real-time PCR (RT-qPCR). Reactive oxygen species (ROS) production was detected using the fluorescent probe DCFH-DA, and mitochondrial membrane potential was evaluated using a fluorescent probe JC-1. The mtROS level was assessed using a fluorescence probe MitoSOX.

RESULTS

DNLA lessened CCl4-induced liver injury, evident by reduced AST and ALT levels and improved liver pathology. DNLA suppressed necroptosis by decreasing RIPK1, RIPK3, and MLKL phosphorylation, concurrently enhancing mitochondrial function. It also broke the positive feedback loop between mtROS and RIPK1/RIPK3/MLKL activation. Similar findings were observed with resveratrol and mitochondrial SOD2 overexpression, both mitigating mtROS and necroptosis. Further mechanistic studies found that DNLA inhibited the oxidation of RIPK1 and reduced its phosphorylation level, whereby lowering the phosphorylation of RIPK3 and MLKL, blocking necroptosis, and alleviating liver injury.

CONCLUSIONS

This study demonstrates that DNLA inhibits the necroptosis signaling pathway by reducing mtROS mediated oxidation of RIPK1, thereby reducing the phosphorylation of RIPK1, RIPK3, and MLKL, and protecting against liver injury.

Crebanine mitigates glucocorticoid-induced osteonecrosis of the femoral head by restoring bone remodelling homeostasis via attenuating oxidative stress

The onset of osteonecrosis of the femoral head (ONFH) is intimately associated with the extensive administration of glucocorticoids (GCs). Long-term stimulation of GCs can induce oxidative stress in both osteoclasts (OCs) and osteoblasts (OBs), resulting in the disturbance of bone remodelling. An alkaloid named crebanine (CN) demonstrates pharmacological properties including anti-inflammation and reactive oxygen species (ROS) modulation. Our objective is to assess the therapeutic potential of CN in treating ONFH and elucidate the associated underlying mechanisms. The network pharmacology analysis uncovered that CN played a role in regulating ROS metabolism. In vitro, CN demonstrated its ability to reduce the dexamethasone (DEX)-stimulated generation of OCs and suppress their resorptive function by downregulating the level of osteoclast marker genes. Concurrently, CN also mitigated DEX-induced damage to OBs, facilitating the restoration of osteoblast marker gene expression, cellular differentiation and function. These effects were achieved by CN augmenting the antioxidant system to reduce intracellular ROS levels. Furthermore, in vitro results were corroborated by micro-CT and histological data, which also showed that CN attenuated MPS-induced ONFH in mice. This study highlights the therapeutic potential of CN in counteracting GCs-induced ONFH.

Dendrobium nobile active ingredient Dendrobin A against hepatocellular carcinoma via inhibiting nuclear factor kappa-B signaling

OBJECTIVE

Dendrobin A, a typical active ingredient of the traditional Chinese medicine Dendrobium nobile, has potential clinical application in cancer treatment; however, its effect and mechanism in anti-hepatocellular carcinoma (HCC) remain unsolved.

METHOD

The effects of Dendrobin A on the viability, migration, invasion, cycle, apoptosis, and epithelial-mesenchymal transition of HepG2 and SK-HEP-1 cells were verified by in vitro experiments. mRNA sequencing was performed to screen the differentially expressed genes (DEGs) of HCC cells before and after Dendrobin A treatment, following GO enrichment and KEGG signaling pathway analyses. Mechanistically, molecular docking was used to evaluate the binding of Dendrobin A with proteins p65 and p50, before further verifying the activation of nuclear factor kappa-B (NF-κB) signaling. Finally, the antiproliferative effect of Dendrobin A on HCC cells was explored through animal experiments.

RESULTS

Dendrobin A arrested cell cycle, induced apoptosis, and inhibited proliferation, migration, invasion, and blocked epithelial-mesenchymal transition in HepG2 and SK-HEP-1 cells. mRNA sequencing identified 830 DEGs, involving various biological processes. KEGG analysis highlighted NF-κB signaling. Molecular docking revealed strong binding of Dendrobin A with p65 and p50 proteins, and western blotting confirmed reduced levels of p-p65 and p-p50 in HCC cells post Dendrobin A treatment. NF-κB agonist PMA reversed Dendrobin A-inhibited cell proliferation migration and invasion. In vivo experiments showed that Dendrobin A inhibited HCC cell growth.

CONCLUSION

Our findings suggest that Dendrobin A exhibits anti-HCC properties by inhibiting the activation of the NF-κB pathway. These results provide a scientific basis for utilizing Dendrobium nobile in anti-HCC therapies.

Geraniol prevents CCl4-induced hepatotoxicity via suppression of hepatic oxidative stress, pro-inflammation and apoptosis in rats

Carbon tetrachloride (CCl4) is a classic chemical hepatotoxicant that triggers liver damage through hepatic exacerbation of oxidative stress. Geraniol (GRL) is a natural bioactive acyclic monoterpene with several pharmacological effects. We thus explored whether GRL could prevent CCl4-triggered hepatic toxicity. Rats were divided and administered GRL (100 mg/kg) and/or CCl4 (1 ml/kg of 1:1 v/v CCl4: olive oil) in Control group, GRL group, CCl4 group, GRL + CCl4 groups 2 times per week for 4 consecutive weeks. CCl4 caused significantly (p < 0.05) elevated serum activities of alkaline phosphatase (ALP), aspartate aminotransferase (AST), alanine aminotransferase (ALT), and total bilirubin (TB), whereas the albumin (ALB) and total protein (TP) levels were significantly (p < 0.05) reduced relative to the control group. The liver activities of catalase (CAT), glutathione peroxidase (GPx), and superoxide dismutase (SOD) decreased significantly (p < 0.05), while malondialdehyde (MDA) level evidently elevated in comparison to the control group. The CCl4 exposure caused significant increases in proinflammatory interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α), apoptotic caspase-3 and caspase-9 levels, whereas the anti-inflammatory interleukin-4 (IL-4) and interleukin-10 (IL-10) were reduced in consistent with histopathological changes compared to the control. On the contrary, the GRL administration prevented the hepatic toxicity and lesions through restoration of liver status markers, antioxidant enzyme activities, MDA, cytokines and apoptosis in comparison to the CCl4 group. Altogether, the findings reveal that GRL could abrogate CCl4-provoked hepatic toxicity via inhibition of hepatic oxidative stress, inflammation and apoptosis in rats.

Activation of Nrf2/HO-1 signaling pathway exacerbates cholestatic liver injury

Nuclear factor erythroid 2-related factor-2 (Nrf2) antioxidant signaling is involved in liver protection, but this generalization overlooks conflicting studies indicating that Nrf2 effects are not necessarily hepatoprotective. The role of Nrf2/heme oxygenase-1 (HO-1) in cholestatic liver injury (CLI) remains poorly defined. Here, we report that Nrf2/HO-1 activation exacerbates liver injury rather than exerting a protective effect in CLI. Inhibiting HO-1 or ameliorating bilirubin transport alleviates liver injury in CLI models. Nrf2 knockout confers hepatoprotection in CLI mice, whereas in non-CLI mice, Nrf2 knockout aggravates liver damage. In the CLI setting, oxidative stress activates Nrf2/HO-1, leads to bilirubin accumulation, and impairs mitochondrial function. High levels of bilirubin reciprocally upregulate the activation of Nrf2 and HO-1, while antioxidant and mitochondrial-targeted SOD2 overexpression attenuate bilirubin toxicity. The expression of Nrf2 and HO-1 is elevated in serum of patients with CLI. These results reveal an unrecognized function of Nrf2 signaling in exacerbating liver injury in cholestatic disease.

PPARα is one of the key targets for dendrobine to improve hepatic steatosis in NAFLD

ETHNOPHARMACOLOGICAL RELEVANCE

Dendrobium nobile Lindl. (DNL) is a traditional Chinese ethnobotanical herb. Dendrobine (DNE) has been designated as a quality indicator for DNL in the Chinese Pharmacopoeia. DNE exhibits various pharmacological activities, including the reduction of blood lipids, regulation of blood sugar levels, as well as anti-inflammatory and antioxidant properties.

AIM OF THE STUDY

The objective of this study is to explore the impact of DNE on lipid degeneration in nonalcoholic fatty liver disease (NAFLD) liver cells and elucidate its specific mechanism. The findings aim to offer theoretical support for the development of drugs related to DNL.

MATERIALS AND METHODS

We utilized male C57BL/6J mice, aged 6 weeks old, to establish a NAFLD model. This model allowed us to assess the impact of DNE on liver pathology and lipid levels in NAFLD mice. We investigated the mechanism of DNE's regulation of lipid metabolism through RNA-seq analysis. Furthermore, a NAFLD model was established using HepG2 cells to further evaluate the impact of DNE on the pathological changes of NAFLD liver cells. The potential mechanism of DNE's improvement was rapidly elucidated using HT-qPCR technology. These results were subsequently validated using mouse liver samples. Following the in vitro activation or inhibition of PPARα function, we observed changes in DNE's ability to ameliorate pathological changes in NAFLD hepatocytes. This mechanism was further verified through RT-qPCR and Western blot analysis.

RESULTS

DNE demonstrated a capacity to enhance serum TC, TG, and liver TG levels in mice, concurrently mitigating liver lipid degeneration. RNA-seq analysis unveiled that DNE primarily modulates the expression of genes related to metabolic pathways in mouse liver. Utilizing HT-qPCR technology, it was observed that DNE markedly regulates the expression of genes associated with the PPAR signaling pathway in liver cells. Consistency was observed in the in vivo data, where DNE significantly up-regulated the expression of PPARα mRNA and its protein level in mouse liver. Additionally, the expression of fatty acid metabolism-related genes (ACOX1, CPT2, HMGCS2, LPL), regulated by PPARα, was significantly elevated following DNE treatment. In vitro experiments further demonstrated that DNE notably ameliorated lipid deposition, peroxidation, and inflammation levels in NAFLD hepatocytes, particularly when administered in conjunction with fenofibrate. Notably, the PPARα inhibitor GW6471 attenuated these effects of DNE.

CONCLUSIONS

In summary, DNE exerts its influence on the expression of genes associated with downstream fat metabolism by regulating PPARα. This regulatory mechanism enhances liver lipid metabolism, mitigates lipid degeneration in hepatocytes, and ultimately ameliorates the pathological changes in NAFLD hepatocytes.

Dendrobium Nobile Alcohol Extract Extends the Lifespan of Caenorhabditis elegans via hsf-1 and daf-16

Dendrobium nobile is a traditional Chinese herb with anti-inflammatory, antioxidant, and neuroprotective properties. However, its antiaging effects are unclear. Herein, we studied the aging-related functions and the mechanism of action of the alcohol extract of Dendrobium nobile (DnAE) in the model organism Caenorhabditis elegans. The results indicated that 1 mg/mL DnAE slowed lipofuscin accumulation, decreased the levels of reactive oxygen species, elevated superoxide dismutase activity, enhanced oxidative and heat stress resistance, extended the lifespan of nematodes, protected their dopamine neurons from 6-hydroxydopamine-induced neurodegeneration, and reduced Aβ-induced neurotoxicity. DnAE upregulated the mRNA expression of the transcription factors DAF-16 and HSF-1, promoted the nuclear localization of DAF-16, and enhanced the fluorescence intensity of HSP-16.2. However, it had no effect on the lifespan of DAF-16 mutants. Thus, DnAE can significantly extend lifespan, enhance heat stress tolerance, and delay age-related diseases through a DAF-16-dependent pathway.

Preparation and evaluation of Angelica sinensis polysaccharide-modified chitosan sponge for acute liver injury protection

In this study, a porous sponge material was formed by physically mixing chitosan (CS) and Angelica sinensis polysaccharide (ASP). After removing the water by freeze-drying, the CS/ASP sponge was obtained. The prepared sponges exhibited excellent swelling properties, thermal stability and biocompatibility as well as improvements over the insufficient mechanical properties of pure chitosan sponges. Notably, the ASP released from the CS/ASP sponge could be effectively absorbed by the liver, which endowed the CS/ASP sponge with effective liver-protective effects against CCl4-induced acute liver injury; these protective effects surpassed those of both blank CS and CS/Dextran sponges. The underlying protective mechanism may involve the activation of the Nrf2-mediated antioxidant signaling pathway and the inhibition of hepatocyte apoptosis. Understanding CS/ASP sponges may provide new insights and inspire new methods for the clinical application of ASP. At the same time, we hope to suggest future directions for the development of polysaccharide preparations.

Age-dependent dendrobine biosynthesis in Dendrobium nobile: insights into endophytic fungal interactions

Introduction

Dendrobium nobile (D. nobile), a valued Chinese herb known for its diverse pharmacological effects, owes much of its potency to the bioactive compound dendrobine. However, dendrobine content varies significantly with plant age, and the mechanisms governing this variation remain unclear. This study delves into the potential role of endophytic fungi in shaping host-microbe interactions and influencing plant metabolism.

Methods

Using RNA-seq, we examined the transcriptomes of 1-year-old, 2-year-old, and 3-year-old D. nobile samples and through a comprehensive analysis of endophytic fungal communities and host gene expression in D. nobile stems of varying ages, we aim to identify associations between specific fungal taxa and host genes.

Results

The results revealing 192 differentially expressed host genes. These genes exhibited a gradual decrease in expression levels as the plants aged, mirroring dendrobine content changes. They were enriched in 32 biological pathways, including phagosome, fatty acid degradation, alpha-linolenic acid metabolism, and plant hormone signal transduction. Furthermore, a significant shift in the composition of the fungal community within D. nobile stems was observed along the age gradient. Olipidium, Hannaella, and Plectospherella dominated in 1-year-old plants, while Strelitziana and Trichomerium prevailed in 2-year-old plants. Conversely, 3-year-old plants exhibited additional enrichment of endophytic fungi, including the genus Rhizopus. Two gene expression modules (mediumpurple3 and darkorange) correlated significantly with dominant endophytic fungi abundance and dendrobine accumulation. Key genes involved in dendrobine synthesis were found associated with plant hormone synthesis.

Discussion

This study suggests that the interplay between different endophytic fungi and the hormone signaling system in D. nobile likely regulates dendrobine biosynthesis, with specific endophytes potentially triggering hormone signaling cascades that ultimately influence dendrobine synthesis.

Basement Membrane-Associated lncRNA Risk Model Predicts Prognosis and Guides Clinical Treatment in Clear Cell Renal Cell Carcinoma

The basement membrane (BM) affects the invasion and growth of malignant tumors. The role and mechanism of BM-associated lncRNAs in clear cell renal cell carcinoma (ccRCC) are unknown. In this study, we identified biomarkers of ccRCC and developed a risk model to assess patient prognosis. We downloaded transcripts and clinical data from the Cancer Genome Atlas (TCGA). Differential analysis, co-expression analysis, Cox regression analysis, and lasso regression were used to identify BM-associated prognostic lncRNAs and create a risk prediction model. We evaluated and validated the accuracy of the model using multiple methods and constructed a nomogram to predict the prognosis of ccRCC. GO, KEGG, and immunity analyses were used to explore differences in biological function. We constructed a risk model containing six BM-associated lncRNAs (LINC02154, IGFL2-AS1, NFE4, AC112715.1, AC092535.5, and AC105105.3). The risk model has higher diagnostic efficiency compared to clinical characteristics and can be used to forecast patient prognoses. We used renal cancer cells and tissue microarrays to verify the expression of lncRNAs in the risk model. We found that knocking down LINC02154 and AC112715.1 could inhibit the invasion ability of renal cancer cells. The risk model based on BM-associated lncRNAs can well predict ccRCC and guide clinical treatment.

Therapeutic potential of the chemical composition of Dendrobium nobile Lindl

Dendrobium nobile Lindl. belongs to the genus Dendrobium of the orchid family and is a valuable herbal medicinal material. The information in this paper has been collected from the scientific literature databases including PubMed, Google Scholar, Web of Science, SciFinder, China National Knowledge Infrastructure, published books, Ph.D., and M.S. dissertations systematically in recent 20 years. "Dendrobium nobile Lindl.," "chemical composition," "pharmacological activities," and "diseases" were used as search terms to screen the literature. The collected chemical compositions are classified and summarized according to their different chemical structures, and the clinical disease treatment effects of Dendrobium nobile Lindl. are classified and summarized based on their pharmacological activities and different experimental disease models. Recent studies have revealed that Dendrobium nobile Lindl. contains chemical components such as alkaloids, bibenzyls, sesquiterpenes, phenanthrenes, and polysaccharides, and that its pharmacological activities are closely related to the chemical components, with pharmacological activities such as anti-tumor, anti-aging, immune enhancement, hypoglycemic, and anti-cataract. Currently, researchers are conducting extensive and detailed studies on Dendrobium nobile Lindl. and research experiments on its chemical constituents in the treatment of various clinical diseases. Therefore, the purpose of this paper is to review the chemical composition of Dendrobium nobile Lindl. and its experimental studies in the treatment of diseases and to provide a scientific reference for the future application of Dendrobium nobile Lindl. in the treatment of diseases.

Alternanthera brasiliana L. extract alleviates carbon tetrachloride-induced liver injury and fibrotic changes in mice: Role of matrix metalloproteinases and TGF-β/Smad axis

ETHNOPHARMACOLOGICAL RELEVANCE

Alternanthera brasiliana L. is a flowering plant belonging to the family Amaranthaceae and is popularly known as "penicillin". It is used in folk medicine to treat infections, coughs, wound healing, and inflammatory diseases.

AIM OF THE STUDY

We investigated the effect of Alternanthera brasiliana L. leaves hydroalcoholic extract (AB) against oxidative stress, inflammation, and fibrotic changes in an experimental model of carbon tetrachloride (CCl₄)-induced liver injury and fibrosis in mice.

MATERIALS AND METHODS

Thirty-six male Balb/C mice were randomized into five groups: normal control, AB control, CCl₄ control, CCl₄ + AB-200 mg/kg, and CCl₄ + AB-400 mg/kg. In mice, liver injury was induced by intraperitoneal injection of CCl₄ (20% in corn oil, 5 ml/kg body weight) thrice a week for six consecutive weeks. AB extract at two doses (200 mg/kg and 400 mg/kg body weight) was administered orally for six consecutive weeks. Liver injury-related serum markers (ALT, AST, ALP), antioxidants (GSH, GST, SOD, and vitamin C), pro-inflammatory cytokines including tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, and IL-18, ultrasonographic and histological alterations, proteins of matrix metalloproteinases (MMPs) and tissue inhibitors of matrix metalloproteinase-1 (TIMP-1), nuclear factor-κB (p65) (NF-κB), nod-like receptor protein 3 (NLRP3), and TGF-β/Smad signaling were accessed. LC-Q-TOF-MS/MS analysis of AB was performed.

RESULTS

AB treatment significantly decreased the CCl₄-induced rise in serum ALT, AST, and ALP activities and improved the histological alterations. Compared with the CCl₄-treated group, treatment with AB significantly restored the hepatic antioxidants and reduced the pro-inflammatory cytokines in the liver. The antioxidant activity of AB may be attributed to its terpenoid constituents, which was confirmed by LC-Q-TOF-MS/MS analysis. The CCl₄-induced rise in expression of MMP-2 and MMP-9 and decrease in TIMP-1 were markedly restored in the AB-treated groups. Further findings revealed a significant reduction in the protein levels of phospho-NF-κB (p65), NLRP3, TGF-β, pSmad2/3, collagen I, and α-smooth muscle actin (α-SMA) in the AB treatment groups.

CONCLUSIONS

The hepatoprotective effect of AB may be attributed to the high content of terpenoid compounds and alleviates liver injury and associated fibrotic changes through modulating MMPs, NF-κB (p65), and the TGF-β/Smad axis.

Dendrobium and its active ingredients: Emerging role in liver protection

Dendrobium is a traditional medicinal plant, which has a variety of clinical applications in China. It has been reported that Dendrobium contains various bioactive components, mainly including polysaccharides and alkaloids. Previous studies have shown that Dendrobium has pharmacological activities including antiviral, anti-inflammatory, and antioxidant effects, as well as immune regulation. Particularly, the anti-aging functions and neuroprotective effects of Dendrobium have been well characterized in a wide array of cell and animal models. In recent years, the effect of Dendrobium on the liver has emerged as a new direction to explore its therapeutic benefits and has received more and more attention. This review is focused on the beneficial effects of Dendrobium on liver toxicity and various liver disorders, which presumably are attributed to a consequence of an array of modes of action due to its multiple bioactive components, and largely lack mechanistic and pharmacokinetic characterization. A particular emphasis is placed on the potential action mechanisms related to Dendrobium's liver protection. Research perspectives in regard to the potential therapeutic application for Dendrobium are also discussed in this review.

Fatty acid metabolites of Dendrobium nobile were positively correlated with representative endophytic fungi at altitude

Introduction

Altitude, as a comprehensive ecological factor, regulates the growth and development of plants and microbial distribution. Dendrobium nobile (D. nobile) planted in habitats at different elevations in Chishui city, also shows metabolic differences and endophytes diversity. What is the triangular relationship between altitude, endophytes, and metabolites?

Methods

In this study, the diversity and species of endophytic fungi were tested by ITS sequencing and metabolic differences in plants were tested by UPLC-ESI-MS/MS. Elevation regulated the colonization of plant endophytic fungal species and fatty acid metabolites in D. nobile.

Results

The results indicate that and high altitude was better for the accumulation of fatty acid metabolites. Therefore, the high-altitude characteristic endophytic floras were screened, and the correlation with fatty acid metabolites of plants was built. The colonization of T. rubrigenum, P. Incertae sedis unclassified, Phoma. cf. nebulosa JZG 2008 and Basidiomycota unclassified showed a significantly positive correlation with fatty acid metabolites, especially 18-carbon-chain fatty acids, such as (6Z,9Z,12Z)-octadeca-6,9,12-trienoic acid, 3,7,11,15-tetramethyl-12-oxohexadeca-2,4-dienoic acid and Octadec-9-en-12-ynoic acid. What is more fascinating is these fatty acids are the essential substrates of plant hormones.

Discussion

Consequently, it was speculated that the D. nobile- colonizing endophytic fungi stimulated or upregulated the synthesis of fatty acid metabolites and even some plant hormones, thus affecting the metabolism and development of D. nobile.

Transcriptome Analysis of Protection by Dendrobium Nobile Alkaloids (DNLA) against Chronic Alcoholic Liver Injury in Mice

Objective: To investigate the protective effects of Dendrobium nobile Lindl. alkaloids (DNLA) against chronic alcoholic liver injury. C57BL/6J mice were fed with the Lieber−DeCarli alcohol diet to induce chronic alcoholic liver injury. DNLA (20 mg/kg/day) was gavaged along with the alcohol diet for 28 days. Liver injury was evaluated by serum enzymes. Triglyceride levels, histopathology, and transcriptome changes were examined by RNA-Seq and qPCR. DNLA decreased serum triglyceride levels in mice receiving alcohol. Hepatocyte degeneration and steatosis were ameliorated by DNLA, as evidenced by H&E and Oil-red O staining. DNLA brought the alcohol-induced aberrant gene expression pattern towards normal. Alcohol induced 787 differentially expressed genes (padj < 0.01). DNLA induced 280 differentially expressed genes to a much less extent. Ingenuity pathway analysis showed that DNLA ameliorated alcohol-induced oxidative stress and xenobiotic metabolism disruption. qPCR verified that DNLA alleviated over-activation of Cyp2a4, Cyp2b10, and Abcc4; attenuated oxidative stress (Hmox1, Gstm3, Nupr1), reduced the expression of Nrf2 genes (Nqo1, Gclc, Vldlr); and rescued some metabolic genes (Insig1, Xbp1, Socs3, Slc10a2). In conclusion, DNLA was effective against alcohol-induced fatty liver disease, and the protection may be attributed to alleviated oxidative stress and restored metabolism homeostasis, probably through modulating nuclear receptor CAR-, PXR-, and Nrf2-mediated gene expression pathways.

Extract of Jasminum grandiflorum L. alleviates CCl4-induced liver injury by decreasing inflammation, oxidative stress and hepatic CYP2E1 expression in mice

Jasminum grandiflorum L. (JG) is a medicinal plant containing many bioactive ingredients. Herein, we analyzed the effects of four different extracts and two compounds of JG on acute liver injury caused by carbon tetrachloride (CCl₄) and underlying molecular mechanisms. 7 weeks old C57BL/6 male mice were used to establish a liver injury model by injecting with 1% CCl₄, 10 mL/kg ip. Four different extracts and two compounds of JG were given to mice by gavage for 3 days. Clinical and histological chemistry assays were performed to assess liver injury. Moreover, hepatic oxidative stress and inflammation related markers were determined by immunohistochemistry and western blotting. As a result, JG extracts and two functional components showed different degree of protect effects against CCl₄-induced liver injury by the decrease of elevated serum transaminases and liver index, and the attenuation of histopathological changes in mice, among which JG extracted with petroleum ether (PET) had the most significant effect. In addition, PET remarkably alleviated hepatic oxidative stress and inflammation. Further studies revealed that PET significantly inhibited the TNF-α expression, signal pathway expression, NF-κB p65 and inflammatory factors IL-1β and IL-6 expression in CCl₄-induced liver injury mice. Nevertheless, hydroxytyrosol (HT) alleviated liver injury by reducing oxidative stress. Apart from PET extract, other extracts of JG can inhibit cytochrome CYP2E1 expression to protect liver tissue. These findings suggest that the extracts and its components of JG possesses the potential protective effects against CCl₄-induced liver injury in mice by exerting antioxidative stress and anti-inflammation.

Natural Composition and Biosynthetic Pathways of Alkaloids in Medicinal Dendrobium Species

Dendrobium is the second biggest genus in the Orchidaceae family, some of which have both ornamental and therapeutic values. Alkaloids are a group of active chemicals found in Dendrobium plants. Dendrobine has emerged specific pharmacological and therapeutic properties. Although Dendrobium alkaloids have been isolated and identified since the 1930s, the composition of alkaloids and their biosynthesis pathways, including metabolic intermediates, alkaloid transporters, concrete genes involved in downstream pathways, and associated gene clusters, have remained unresolved scientific issues. This paper comprehensively reviews currently identified and tentative alkaloids from the aspect of biogenic pathways or metabolic genes uncovered based on the genome annotations. The biosynthesis pathways of each class of alkaloids are highlighted. Moreover, advances of the high-throughput sequencing technologies in the discovery of Dendrobium alkaloid pathways have been addressed. Applications of synthetic biology in large-scale production of alkaloids are also described. This would serve as the basis for further investigation into Dendrobium alkaloids.

Mitochondrial Targeting Therapeutics: Promising Role of Natural Products in Non-alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) has become one of the most common chronic liver diseases worldwide, and its prevalence is still growing rapidly. However, the efficient therapies for this liver disease are still limited. Mitochondrial dysfunction has been proven to be closely associated with NAFLD. The mitochondrial injury caused reactive oxygen species (ROS) production, and oxidative stress can aggravate the hepatic lipid accumulation, inflammation, and fibrosis. which contribute to the pathogenesis and progression of NAFLD. Therefore, pharmacological therapies that target mitochondria could be a promising way for the NAFLD intervention. Recently, natural products targeting mitochondria have been extensively studied and have shown promising pharmacological activity. In this review, the recent research progress on therapeutic effects of natural-product-derived compounds that target mitochondria and combat NAFLD was summarized, aiming to provide new potential therapeutic lead compounds and reference for the innovative drug development and clinical treatment of NAFLD.

Identification, Biological Activities and Biosynthetic Pathway of Dendrobium Alkaloids

Dendrobium is a genus of flowering plants belonging to the Orchidaceae family with more than 1,400 species. Many Dendrobium species have been used as medicinal plants in several Asian countries for thousands of years. Alkaloids were reported as the major biological markers due to their complex chemical compositions and various types. In this review, we summarized the structural types of alkaloids, their pharmacological activities, as well as the mechanisms of biological activities. More than sixty alkaloids were isolated and identified from the Dendrobium genus. Moreover, the pharmacological effects of Dendrobium alkaloids as hepatic lipid and gluconeogenesis regulation, as neuroprotection, and as anti-tumor, anti-inflammatory, anti-diabetes, and anti-virus factors were described. Besides, the total chemical synthesis of dendrobine is provided, while the biosynthetic pathway of dendrobine has been proposed based on the functions of associated genes. For applications of these invaluable herbs, more researches on the extraction of biological markers from compounds are needed. Further confirmation of the proposed biosynthetic pathways is anticipated as well.

Dendrobium nobile Lindl. alkaloids alleviate Mn-induced neurotoxicity via PINK1/Parkin-mediated mitophagy in PC12 cells

Modern pharmacological studies have demonstrated that Dendrobium nobile Lindl. Alkaloids (DNLA), the main active ingredients of Dendrobium nobile, is valuable as an anti-aging and neuroprotective herbal medicine. The present study was designed to determine whether DNLA confers protective function over neurotoxicant manganese (Mn)-induced cytotoxicity and the mechanism involved. Our results showed that pretreatment of PC12 cells with DNLA alleviated cell toxicity induced by Mn and improved mitochondrial respiratory capacity and oxidative status. Mn treatment increased apoptotic cell death along with a marked increase in the protein expression of Bax and a decrease in the expression of Bcl-2 protein, all of which were noticeably reversed by DNLA. Furthermore, DNLA significantly abolished the decrease in protein levels of both PINK1 and Parkin, and mitigated the increased expression of autophagy marker LC3-II and accumulation of p62 caused by Mn. These results demonstrate that DNLA inhibits Mn induced cytotoxicity, which may be mediated through modulating PINK1/Parkin-mediated autophagic flux and improving mitochondrial function.

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Dendrobium nobile Lindl. alkaloids (DNLA) significantly alleviate cytotoxicity of PC12 cells induced by manganese (Mn) and improve mitochondrial function.

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Activation of PINK1/Parkin-mediated autophagic flux is involved in the protective action of DNLA on Mn-induced neurotoxicity.

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DNLA reduces Mn-induced ROS generation and suppresses Mn-induced apoptosis.

RNA-Seq analysis of the protection by Dendrobium nobile alkaloids against carbon tetrachloride hepatotoxicity in mice

OBJECTIVE

Dendrobium nobile is a genuine Chinese medicine. Dendrobium nobile Lindl. alkaloids (DNLA) protects against CCl₄-induced acute liver injury. This study used RNA-Seq to explore the mechanisms.

METHODS

Mice were pretreated with DNLA (10 and 20 mg/kg, po) for 7 days, and subsequently intoxicated with CCl₄ (20 μL/kg, ip for 24 h). Liver RNA was extracted and subjected to RNA-Seq. The bioinformatics, including PCA, GO, KEGG, two-dimensional clustering, Ingenuity Pathways Analysis (IPA), and Illumina BaseSpace Correlation Engine (BSCE) were used to analyze the data. qPCR was performed on selected genes to verify RNA-Seq results.

RESULTS

DNLA protection against CCl₄ hepatotoxicity was confirmed by histopathology. PCA revealed the distinct gene expression patterns between the different treatment groups. GO showed that CCl₄ induced the activation, adhesion and proliferation of immune cells. KEGG showed CCl₄ induced oxidative stress, diseases and compromised adaptive responses. CCl₄ induced differentially expressed genes (DEGs) were identified by DESeq2 with Padj < 0.05 and 2D-clustered with other groups. DNLA reverted CCl₄-induced DEGs in a dose-dependent manner. qPCR analysis of S100 g, Sprr1, CCL3/7, Saa2/3, IL1rn, Cox7a2 and Rad15 confirmed RNA-Seq results. IPA showed that CCl₄ treatment altered some signaling and metabolic pathways, which were ameliorated or returned to normal following DNLA treatment. The CCl₄-activated mitochondrial oxidative phosphorylation was illustrated as an example. IPA Upstream Regulator Analysis further revealed the activated or inhibited molecules and chemicals that are responsible for CCl₄-induced DEGs, and DNLA attenuated these changes. BSCE analysis verified that CCl₄-induced DEGs were highly correlated with the GEO database of CCl₄ hepatotoxicity in rodents, and DNLA dose-dependently attenuated such correlation.

CONCLUSION

RNA-Seq revealed CCl₄-induced DEGs, disruption of canonical pathways, activation or inhibition of upstream regulators, which are highly correlated with database for CCl₄ hepatotoxicity. All these changes were attenuated or returned to normal by DNLA, demonstrating the mechanisms for DNLA to protect against CCl₄ hepatotoxicity.