HPLC-based metabolomics of Dendrobium officinale revealing its antioxidant ability

Beneficial Effects of Dendrobium officinale Extract on Insomnia Rats Induced by Strong Light and Noise via Regulating GABA and GABAA Receptors

OBJECTIVE

To explore the therapeutic effects and underlying mechanisms of Dendrobium officinale (Tiepi Shihu) extract (DOE) on insomnia.

METHODS

Forty-two male Sprague-Dawley rats were randomly divided into 6 groups (n=7 per group): normal control, model control, melatonin (MT, 40 mg/kg), and 3-dose DOE (0.25, 0.50, and 1.00 g/kg) groups. Rats were raised in a strong-light (10,000 LUX) and -noise (>80 db) environment (12 h/d) for 16 weeks to induce insomnia, and from week 10 to week 16, MT and DOE were correspondingly administered to rats. The behavior tests including sodium pentobarbital-induced sleep experiment, sucrose preference test, and autonomous activity test were used to evaluate changes in sleep and emotions of rats. The metabolic-related indicators such as blood pressure, blood viscosity, blood glucose, and uric acid in rats were measured. The pathological changes in the cornu ammonis 1 (CA1) region of rat brain were evaluated using hematoxylin and eosin staining and Nissl staining. Additionally, the sleep-related factors gamma-aminobutyric acid (GABA), glutamate (GA), 5-hydroxytryptamine (5-HT), and interleukin-6 (IL-6) were measured using enzyme linked immunosorbent assay. Finally, we screened potential sleep-improving receptors of DOE using polymerase chain reaction (PCR) array and validated the results with quantitative PCR and immunohistochemistry.

RESULTS

DOE significantly improved rats' sleep and mood, increased the sodium pentobarbital-induced sleep time and sucrose preference index, and reduced autonomic activity times (P<0.05 or P<0.01). DOE also had a good effect on metabolic abnormalities, significantly reducing triglyceride, blood glucose, blood pressure, and blood viscosity indicators (P<0.05 or P<0.01). DOE significantly increased the GABA content in hippocampus and reduced the GA/GABA ratio and IL-6 level (P<0.05 or P<0.01). In addition, DOE improved the pathological changes such as the disorder of cell arrangement in the hippocampus and the decrease of Nissel bodies. Seven differential genes were screened by PCR array, and the GABAA receptors (Gabra5, Gabra6, Gabrq) were selected for verification. The results showed that DOE could up-regulate their expressions (P<0.05 or P<0.01).

CONCLUSION

DOE demonstrated remarkable potential for improving insomnia, which may be through regulating GABAA receptors expressions and GA/GABA ratio.

Anti-Inflammatory Effect of Dendrobium officinale Extract on High-Fat Diet-Induced Obesity in Rats: Involvement of Gut Microbiota, Liver Transcriptomics, and NF-κB/IκB Pathway

The growing prevalence of obesity is being increasingly acknowledged as a major public health issue. This mainly stems from the excessive intake of dietary fats. Dendrobium officinale (DO), recognized as an herb with dual roles of food and medicine, is renowned for its diverse health-promoting effects. Nevertheless, the specifics of its antiobesity and anti-inflammatory properties and the underlying mechanisms are still obscure. The present study shows that treatment with Dendrobium officinale extract (DOE) alleviates obesity, liver steatosis, inflammation, and oxidative stress in rats that are obese due to a high-fat diet (HFD). Firstly, with respect to HFD obese rats, higher doses of DOE significantly reduced TG, TC, LDL-C, blood glucose, and liver AST and ALT, along with lipid droplets. Meanwhile, DOE supplementation significantly reduced oxidative stress induced by ROS and MDA and increased the levels of GSH-Px and SOD in liver tissues. Furthermore, integrated analysis of transcriptomic and microbiomic data revealed that DOE modulated inflammatory responses through the NF-κB/IκB pathway. This regulatory mechanism was evidenced by corresponding changes in the protein expression levels of both NF-κB and IκB. Additionally, DOE was found to modulate gut microbiota composition in obese rats, specifically reducing the relative abundance of Bilophila while increasing beneficial bacterial populations, particularly the genera Akkermansia and Roseburia. These findings suggest that DOE may help retain the homeostasis of the gut microbiota and improve metabolic health by regulating inflammation in the liver and intestine, thereby providing protection against obesity and related metabolic syndromes. Our study demonstrates that DOE, as a natural botanical extract, can effectively facilitate the prevention or treatment of metabolic syndrome through precision dietary interventions.

Multidimensional evaluation of quality differences for Dendrobium officinale stems grown under different cultivation environments based on widely targeted metabolomics, network pharmacology, molecular docking, and cell experiments

Introduction

Dendrobium officinale is an endangered perennial epiphytic herbaceous plant. In the Chinese Pharmacopoeia, the dried stems of D. officinale are used medicinally and are commonly utilized as a medicinal and food homologous product. Notable variations in the quality of D. officinale stems are observed across different cultivation environments; however, the underlying mechanisms remain unclear.

Methods

Metabolites in D. officinale stems grown in stone epiphytic, tree epiphytic, and greenhouse environments were identified using UPLC-MS/MS-based widely targeted metabolomics. Differential metabolites from stems grown in different cultivation environments were selected for studies on quality differences. Network pharmacology was employed to investigate the core targets of these differential metabolites, and molecular docking validation was conducted with these metabolites to identify quality markers. Finally, a combination of network pharmacology and in vitro experimental results was used to explore the reasons behind the differences in therapeutic effects of D. officinale stems grown in various cultivation environments.

Results

A total of 1929 primary and secondary metabolites were identified. Compared to the tree epiphytic and greenhouse environments, 58 primary and secondary metabolites were up-regulated in the stone epiphytic environment. Among these, 7 amino acids and their derivatives were exclusively found as up-regulated primary metabolites, while 18 flavonoids constituted the main up-regulated secondary metabolites. The binding affinities of the 18 flavonoids to the core targets (MAOA and TNF) were superior to those of other up-regulated metabolites, and they can be utilized in quality difference studies, particularly nicotiflorin and isoquercitrin. Stems grown in the stone epiphytic environment showed a superior protective effect on chronic atrophic gastritis cells compared to the other two environments. This was associated with increased binding of differential metabolites to targets such as MAOA and TNF and decreased binding to targets such as SRC and PTGS2.

Discussion

The composition and content of metabolites in D. officinale stems are influenced by the cultivation environment, which in turn affects the therapeutic effects of the stems. The change of the target preference could be the reason for the difference in drug efficacy. This study introduces a novel approach for distinguishing the quality of D. officinale stems grown under different cultivation environments and exploring the variations in their therapeutic effects.

Dynamic Changes in Functional Components of Dendrobium officinale and Their Applications in Food Science: A Review

Dendrobium officinale is a medicinal and edible plant whose bioactive components, including polysaccharides, alkaloids, flavonoids, and phenolic compounds, exhibit antioxidant, anti-inflammatory, immune-regulating, and digestive-promoting effects. This review outlines the functional roles of Dendrobium's bioactive components, systematically exploring their accumulation patterns across different growth stages and environmental conditions, as well as their applications in the food industry. The literature review reveals that specific accumulation patterns occur of secondary metabolites, with these compounds accumulating most during the flowering and fruiting stages. Previous studies have also shown that environmental factors, such as light, temperature, and water, significantly influence the synthesis and accumulation of these compounds. Finally, the review discusses the development and application prospects of D. officinale in the beauty, health, and gourmet food sectors. In conclusion, this review provides theoretical support for high-quality cultivation of D. officinale and the stability of its functional components.

Characterization of the Composition of Bioactive Fractions from Dendrobium officinale Flowers That Protect against H2O2-Induced Oxidative Damage through the PI3K/AKT/Nrf2 Pathway

Dendrobium officinale flowers (DOF) have previously been established as a promising source of natural antioxidants, and it is ideally suited for processing to prepare functional foods and food additives. The precise extraction processes employed, however, can alter the composition and antioxidant properties of the resultant products, and the characteristic compounds associated with the active fractions prepared from DOF or their mechanisms of action have yet to be reported. To clarify the molecular mechanisms through which these active fractions function for the first time, chromatography was used to separate DOF extracts, yielding five fractions (Fr. (a-e)). Analyses of the antioxidant activity for these different fractions revealed that Fr. (d) presented with the most robust bioactivity. Levels of total flavonoids were then measured, revealing that antioxidant activity levels were positively correlated with total flavonoid content. Fr. (d) was found to contain 20 flavonoids in HPLC-Triple-TOF-MS/MS analyses. At the cellular level, Fr. (d) was found to induce increases in the levels of protective antioxidant factors (SOD and GSH-Px) while reducing the levels of reactive oxygen species (ROS), damage-associated factors (MDA, NO, TNF-α, IL-1β, and IL-6), and inducible nitric oxide synthase (iNOS) expression in C2C12 cells that had been stimulated with H2O2. These data thus provided support for Fr. (d) prevention of oxidative stress and inflammation. Network pharmacology analyses further suggested that Fr. (d) can help protect against oxidative stress through its effects on PI3K/Akt-related signaling activity. Fr. (d) was subsequently found to upregulate PI3K/Akt pathway-related proteins, nuclear transcription factor 2 (Nrf2), and heme oxygenase 1 (HO-1) in addition to suppressing Kelch-like epoxide-related protein 1 (Keap1) expression. In summary, Fr. (d) was found to suppress PI3K/Akt/Nrf2 pathway activation, ultimately alleviating inflammation and oxidative stress as predicted with a network pharmacology approach. Future studies aimed at clarifying the composition and mechanistic activity of DOF Fr. (d) will likely help establish it as a functional food capable of promoting health and longevity.

Visualization of the Infection and Colonization Process of Dendrobium officinale Using a Green Fluorescent Protein-Tagged Isolate of Fusarium oxysporum

Dendrobium officinale soft rot is a widespread and destructive disease caused by Fusarium oxysporum that can seriously affect yield and quality. To better understand the fungal infection and colonization, we successfully created an F. oxysporum labeled with green fluorescent protein using the Agrobacterium tumefaciens-mediated transformation method. Transformants had varying fluorescence intensities, but their pathogenicity did not differ from that of the wild type. Fluorescence microscopy revealed that F. oxysporum primarily entered the aboveground portion of D. officinale through the leaf margin, stomata, or by direct penetration of the leaf surface. It then colonized the mesophyll and spread along its vascular bundles. D. officinale exhibited typical symptoms of decay and wilting at 14 days postinoculation, accompanied by a pronounced fluorescence signal in the affected area. The initial colonization of F. oxysporum in the subterranean region primarily involved attachment to the root hair and epidermis, which progressed to the medullary vascular bundle. At 14 days postinoculation, the root vascular bundles of D. officinale exhibited significant colonization by F. oxysporum. Macroconidia were also observed in black rot D. officinale tissue. In particular, the entire root was surrounded by a significant number of chlamydospore-producing F. oxysporum mycelia at 28 days postinoculation. This approach allowed for the visualization of the complete infection process of F. oxysporum and provided a theoretical foundation for the development of field control strategies.

Metabolic and Transcriptomic Profile Revealing the Differential Accumulating Mechanism in Different Parts of Dendrobium nobile

Dendrobium nobile is an important orchid plant that has been used as a traditional herb for many years. For the further pharmaceutical development of this resource, a combined transcriptome and metabolome analysis was performed in different parts of D. nobile. First, saccharides, organic acids, amino acids and their derivatives, and alkaloids were the main substances identified in D. nobile. Amino acids and their derivatives and flavonoids accumulated strongly in flowers; saccharides and phenols accumulated strongly in flowers and fruits; alkaloids accumulated strongly in leaves and flowers; and a nucleotide and its derivatives and organic acids accumulated strongly in leaves, flowers, and fruits. Simultaneously, genes for lipid metabolism, terpenoid biosynthesis, and alkaloid biosynthesis were highly expressed in the flowers; genes for phenylpropanoids biosynthesis and flavonoid biosynthesis were highly expressed in the roots; and genes for other metabolisms were highly expressed in the leaves. Furthermore, different members of metabolic enzyme families like cytochrome P450 and 4-coumarate-coA ligase showed differential effects on tissue-specific metabolic accumulation. Members of transcription factor families like AP2-EREBP, bHLH, NAC, MADS, and MYB participated widely in differential accumulation. ATP-binding cassette transporters and some other transporters also showed positive effects on tissue-specific metabolic accumulation. These results systematically elucidated the molecular mechanism of differential accumulation in different parts of D. nobile and enriched the library of specialized metabolic products and promising candidate genes.

Identification and application of an endophytic fungus Arcopilus aureus from Panax notoginseng against crop fungal disease

Endophytic fungi are important microbial resources for developing novel antibacterial and antifungal drugs to prevent and control crop diseases. Panax notoginseng has been used as a Chinese medicinal herb for a long time, as it has various bioactivities. However, information on endophytic fungi isolated from Panax notoginseng is rare. In this study, an endophytic fungus known as SQGX-6, which was later identified as the golden hair fungus Arcopilus aureus, was isolated from Panax notoginseng. SQGX-6 was extracted using ethyl acetate, and the active components of the fungus were identified using ultra-performance liquid chromatography-mass spectrometry (UHPLC-MS). The antifungal and antioxidant activities of the extract were determined and evaluated in vitro and in vivo. SQGX-6 and its extract inhibited the growth of Corn stalk rot (Fusarium graminearum), Corn southern leaf blight (Helminthosporium maydis), and Tomato gray mold (Botrytis cinerea) in vitro. The free radical scavenging rates for 2,2-Diphenyl-1-pyridinyl hydrazide (DPPH) radical scavenging activity, 3-Ethylbenzothiazoline-6-Sulfonic Acid Radical scavenging (ABTS) activity were also downregulated by the SQGX-6 extract. In vivo, the SQGX-6 extract inhibited the mycelial growth rates of the three aforementioned fungi and downregulated malondialdehyde (MDA) content and upregulated peroxidase (POD) and phenylalanine ammonia-lyase (PAL) content in fruits, leading to significant reduction in damage to cherry tomatoes caused by Botrytis cinerea. UHPLC-MS was performed to identify various active substances, including Alkaloids, Azoles, Benzofurans, Coumarins, Flavonoids, Organic acids, Phenols, and plant growth regulators contained in the extract. These results suggested that the endophytic fungus SQGX-6 of Panax notoginseng and its extract have excellent antifungal and antioxidant activities, and thus, it is an important microbial resource for the developing novel drugs against plant fungal infections.

Plant-Wide Target Metabolomics Provides a Novel Interpretation of the Changes in Chemical Components during Dendrobium officinale Traditional Processing

The traditional processing of Dendrobium officinale (DO) is performed in five necessary processing steps: processing fresh strips, drying at 85 °C, curling, molding, and drying at 35 °C (Fengdou). The antioxidant activity of DO is increased after it is processed into Fengdou. To comprehensively analyze the changes in the functional components, a plant-wide target metabolomics approach was employed. In total, 739 differential chemical components were identified in five processing treatments, mainly highlighting differences in the levels of phenolic acids, flavonoids, lipids, and amino acids and their derivatives, and the glycosylation of aglycone resulted in the upregulation of flavonoid glycoside levels. Temperature is a key factor in DO processing during production. In addition, the enrichment of specific differential chemical components was found mainly in five different metabolic pathways: glucosinolate biosynthesis, linoleic acid metabolism, flavonoid biosynthesis, phenylpropanoid biosynthesis, and ubiquinone and other terpene quinone biosynthesis. A correlation analysis clarified that total phenols and flavonoids show a significant positive correlation with antioxidant capacity. This study provides new insights into the influence of the processing processes on DO quality, which may provide guidance for the high-quality production of DO.

Natural product osthole can significantly disrupt cell wall integrity and dynamic balance of Fusarium oxysporum

Dendrobium officinale Kimura et Migo is a traditional Chinese herbal medicinal plant. However, the frequent occurrence of soft rot disease (SRD) is one of the most harmful diseases in D. officinale production in recent years, which can seriously affect its yield and quality. In this study, the major pathogenic fungus (SR-1) was isolated from D. officinale with typical symptoms of SRD, and was identified as Fusarium oxysporum through morphological and molecular identification. The biological activities of five natural products were determined against F. oxysporum using a mycelial growth inhibition assay. The results showed that osthole had the highest antifungal activity against F. oxysporum, with an EC50 value of 6.40 mg/L. Scanning electron microscopy (SEM) showed that osthole caused F. oxysporum mycelia to shrink and deform. Transmission electron microscopy (TEM) showed that the organelles were blurred and the cell wall was thickened in the presence of osthole. The sensitivity of F. oxysporum to calcofluor white (CFW) staining was significantly enhanced by osthole. Relative conductivity measurements and propidium iodide (PI) observation revealed that osthole had no significant effect on the cell membrane. Further experiments showed that the activity of chitinase and β-1,3-glucanase were decreased, and expression levels of chitinase and β-1,3-glucanase related genes were significantly down-regulated after treatment with osthole. In conclusion, osthole disrupted the cell wall integrity and dynamic balance of F. oxysporum, thereby inhibiting normal mycelial growth.

Revealing of Intracellular Antioxidants in Dendrobium nobile by High Performance Liquid Chromatography-Tandem Mass Spectrometry

The medicinal plant Dendrobium nobile is an important natural antioxidant resource. To reveal the antioxidants of D. nobile, high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was employed for metabolic analysis. The H₂O₂-induced oxidative damage was used in human embryonic kidney 293T (H293T) cells to assess intracellular antioxidant activities. Cells incubated with flower and fruit extracts showed better cell survival, lower levels of reactive oxygen species (ROS), and higher catalase and superoxide dismutase activities than those incubated with root, stem, and leaf extracts (p < 0.01). A total of 13 compounds were newly identified as intracellular antioxidants by association analysis, including coniferin, galactinol, trehalose, beta-D-lactose, trigonelline, nicotinamide-N-oxide, shikimic acid, 5'-deoxy-5'-(methylthio)adenosine, salicylic acid, isorhamnetin-3-O-neohespeidoside, methylhesperidin, 4-hydroxybenzoic acid, and cis-aconitic acid (R² > 0.8, Log₂FC > 1, distribution > 0.1%, and p < 0.01). They showed lower molecular weight and higher polarity, compared to previously identified in vitro antioxidants in D. nobile (p < 0.01). The credibility of HPLC-MS/MS relative quantification was verified by common methods. In conclusion, some saccharides and phenols with low molecular weight and high polarity helped protect H293T cells from oxidative damage by increasing the activities of intracellular antioxidant enzymes and reducing intracellular ROS levels. The results enriched the database of safe and effective intracellular antioxidants in medicinal plants.