Dendrobine-type alkaloids and bibenzyl derivatives from Dendrobium findlayanum

Diterpenoids from Torreya grandis and their cytotoxic activities

Eight previously undescribed diterpenoids, along with eleven previously reported analogues, were obtained from the supercritical CO2 extracts of Torreya grandis aril. The structures of these compounds were elucidated based on HRESIMS, NMR, ECD, and single-crystal X-ray diffraction data. In the MTT assay, compound 18 exhibited significant inhibitory effects on two human colon cancer cell lines, HT-29 and HCT 116 cells, with IC50 values of 7.37 μM and 6.55 μM, respectively. It was found that compound 18 induced apoptosis and significantly inhibited the migration of HCT 116 colon cancer cells in a concentration-dependent manner.

Exploring the Biomedical Potential of Terpenoid Alkaloids: Sources, Structures, and Activities

Terpenoid alkaloids are recognized as a class of compounds with limited numbers but potent biological activities, primarily derived from plants, with a minor proportion originating from animals and microorganisms. These alkaloids are synthesized from the same prenyl unit that forms the terpene skeleton, with the nitrogen atom introduced through β-aminoethanol, ethylamine, or methylamine, leading to a range of complex and diverse structures. Based on their skeleton type, they can be categorized into monoterpenes, sesquiterpenes, diterpenes, and triterpene alkaloids. To date, 289 natural terpenoid alkaloids, excluding triterpene alkaloids, have been identified in studies published between 2019 and 2024. These compounds demonstrate a spectrum of biological activities, including anti-inflammatory, antitumor, antibacterial, analgesic, and cardioprotective effects, making them promising candidates for further development. This review provides an overview of the sources, chemical structures, and biological activities of natural terpenoid alkaloids, serving as a reference for future research and applications in this area.

Enhancing dendrobine production in Dendrobium nobile through mono-culturing of endophytic fungi, Trichoderma longibrachiatum (MD33) in a temporary immersion bioreactor system

Introduction

Dendrobine, a valuable alkaloid found in Dendrobium nobile, possesses significant pharmaceutical potential.

Methods

In this study, we explored innovative approaches to enhance dendrobine production by utilizing endophytic fungi in a Temporary Immersion Bioreactor System (TIBS, Nanjing BioFunction Co. Ltd., China) and traditional test bottles. Dendrobine was unequivocally identified and characterised in D. nobile co-culture seedlings through UHPLC analysis and LC-MS qTOF analysis, supported by reference standards.

Results

The CGTB (control group) and EGTB (experimental group) 12-month-old D. nobile seedlings exhibited similar peak retention times at 7.6±0.1 minutes, with dendrobine identified as C16H25NO2 (molecular weight 264.195). The EGTB, co-cultured with Trichoderma longibrachiatum (MD33), displayed a 2.6-fold dendrobine increase (1804.23 ng/ml) compared to the CGTB (685.95 ng/ml). Furthermore, a bioanalytical approach was applied to investigate the mono-culture of T. longibrachiatum MD33 with or without D. nobile seedlings in test bottles. The newly developed UHPLC-MS method allowed for dendrobine identification at a retention time of 7.6±0.1 minutes for control and 7.6±0.1 minutes for co-culture. Additionally, we explored TIBS to enhance dendrobine production. Co-culturing D. nobile seedlings with Trichoderma longibrachiatum (MD33) in the TIBS system led to a substantial 9.7-fold dendrobine increase (4415.77 ng/ml) compared to the control (454.01 ng/ml) after just 7 days. The comparative analysis of dendrobine concentration between EGTB and EGTIBS highlighted the remarkable potential of TIBS for optimizing dendrobine production. Future research may focus on scaling up the TIBS approach for commercial dendrobine production and investigating the underlying mechanisms for enhanced dendrobine biosynthesis in D. nobile. The structural elucidation of dendrobine was achieved through 1H and 13C NMR spectroscopy, revealing a complex array of proton environments and distinct carbon environments, providing essential insights for the comprehensive characterization of the compound.

Discussion

These findings hold promise for pharmaceutical and industrial applications of dendrobine and underline the role of endophytic fungi in enhancing secondary metabolite production in medicinal plants.

Systematic analysis of proximal midgut- and anorectal-originating contractions in larval zebrafish using event feature detection and supervised machine learning algorithms

BACKGROUND

Zebrafish larvae are translucent, allowing in vivo analysis of gut development and physiology, including gut motility. While recent progress has been made in measuring gut motility in larvae, challenges remain which can influence results, such as how data are interpreted, opportunities for technical user error, and inconsistencies in methods.

METHODS

To overcome these challenges, we noninvasively introduced Nile Red fluorescent dye to fill the intraluminal gut space in zebrafish larvae and collected serial confocal microscopic images of gut fluorescence. We automated the detection of fluorescent-contrasted contraction events against the median-subtracted signal and compared it to manually annotated gut contraction events across anatomically defined gut regions. Supervised machine learning (multiple logistic regression) was then used to discriminate between true contraction events and noise. To demonstrate, we analyzed motility in larvae under control and reserpine-treated conditions. We also used automated event detection analysis to compare unfed and fed larvae.

KEY RESULTS

Automated analysis retained event features for proximal midgut-originating retrograde and anterograde contractions and anorectal-originating retrograde contractions. While manual annotation showed reserpine disrupted gut motility, machine learning only achieved equivalent contraction discrimination in controls and failed to accurately identify contractions after reserpine due to insufficient intraluminal fluorescence. Automated analysis also showed feeding had no effect on the frequency of anorectal-originating contractions.

CONCLUSIONS & INFERENCES

Automated event detection analysis rapidly and accurately annotated contraction events, including the previously neglected phenomenon of anorectal contractions. However, challenges remain to discriminate contraction events based on intraluminal fluorescence under treatment conditions that disrupt functional motility.

Anti-inflammatory and α-glucosidase inhibitory constituents from Dendrobium nobile Lindl

Four new compounds ((±)-1-3), including one pair of enantiomers ((±)-1), along with 11 known bibenzyls (4-14) were isolated from Dendrobium nobile. The structures of the new compounds were elucidated by spectroscopic methods including 1D and 2D NMR as well as HRESIMS. The configurations of (±)-1 were established via the electronic circular dichroism (ECD) calculations. Compounds (+)-1 and 13 displayed pronounced α-glucosidase inhibitory activities with IC50 values of 16.7 ± 2.3 and 13.4 ± 0.2 μM, respectively, which were comparable to that of genistein (IC50, 8.54 ± 0.69 μM). Kinetic studies revealed that (+)-1 and 13 were non-competitive inhibitors against α-glucosidase and molecular docking simulations illuminated their interactions with α-glucosidase. All the isolates were also evaluated for their anti-inflammatory activities. Compounds 4, 5, and 11 exhibited superior inhibition activity with IC50 values ranging from 9.2 to 13.8 μM to that of quercetin (IC50, 16.3 ± 1.1 μM).

Polysaccharides Extracted from Dendrobium officinale Grown in Different Environments Elicit Varying Health Benefits in Caenorhabditis elegans

Dendrobium officinale is one of the most widely used medicinal herbs, especially in Asia. In recent times, the polysaccharide content of D. officinale has garnered attention due to the numerous reports of its medicinal properties, such as anticancer, antioxidant, anti-diabetic, hepatoprotective, neuroprotective, and anti-aging activities. However, few reports of its anti-aging potential are available. Due to high demand, the wild D. officinale is scarce; hence, alternative cultivation methods are being employed. In this study, we used the Caenorhabditis elegans model to investigate the anti-aging potential of polysaccharides extracted from D. officinale (DOP) grown in three different environments; tree (TR), greenhouse (GH), and rock (RK). Our findings showed that at 1000 µg/mL, GH-DOP optimally extended the mean lifespan by 14% and the maximum lifespan by 25% (p < 0.0001). TR-DOP and RK-DOP did not extend their lifespan at any of the concentrations tested. We further showed that 2000 µg/mL TR-DOP, GH-DOP, or RK-DOP all enhanced resistance to H₂O₂-induced stress (p > 0.05, p < 0.01, and p < 0.01, respectively). In contrast, only RK-DOP exhibited resistance (p < 0.01) to thermal stress. Overall, DOP from the three sources all increased HSP-4::GFP levels, indicating a boost in the ability of the worms to respond to ER-related stress. Similarly, DOP from all three sources decreased α-synuclein aggregation; however, only GH-DOP delayed β-amyloid-induced paralysis (p < 0.0001). Our findings provide useful information on the health benefits of DOP and also provide clues on the best practices for cultivating D. officinale for maximum medicinal applications.

Complete 1 H and 13 C assignments of two new sesquiterpenoids from Dendrobium aduncum

Two new sesquiterpenoids, dendroaduoid A (1) and dendroaduol (2), together with four known sesquiterpenoids were isolated from the stems of Dendrobium aduncum. Their structures were identified by HR-ESI-MS and NMR experiments, and the complete assignments of ¹ H and ¹³ C NMR data for two new sesquiterpenoids were obtained by the aid of HSQC, HMBC, ¹ H-¹ H COSY, NOESY, and ECD techniques. The cytotoxic effects of the isolated compounds on four tumor cell lines (HCT-116, HepG2, A549, and SW1990) were evaluated using MTT assay. Otherwise, the inhibitory activity of these six sesquiterpenoids on glycosidase was also evaluated.

Dendrobium as a new natural source of bioactive for the prevention and treatment of digestive tract diseases: A comprehensive review with future perspectives

BACKGROUND

The incidence of diseases related to the digestive tract is on the rise, with many types of complex etiologies. Dendrobium nobile Lindl. is a famous Traditional Chinese Medicine (TCM) rich in many bioactives proven to be beneficial in several health diseases related to inflammation and oxidative stress.

PURPOSE

At present, despite the availability of various therapeutic clinical drugs used for the treatment of digestive tract diseases, resistance emergence and existence of several side effects warrant for the developing of novel drugs for improved effects on digestive tract diseases.

METHODS

"Orchidaceae", "Dendrobium", "inflammation", "digestive tract", and "polysaccharide" were used as search terms to screen the literature. The therapeutic use of Dendrobium related to digestive tract diseases relative to known polysaccharides and other bioactive compounds were derived from online databases, including Web of Science, PubMed, Elsevier, Science Direct, and China National Knowledge Infrastructure, as well as relevant information on the known pharmacological actions of the listed phytochemicals.

RESULTS

To better capitalize upon Dendrobium for preventing and treating diseases related to digestive tract, this review summarizes bioactives in Dendrobium reported of potential in digestive tract diseases management and their underlying action mechanisms. Studies revealed that Dendrobium encompasses diverse classes including polysaccharides, phenolics, alkaloids, bibenzyls, coumarins, phenanthrene and steroids, with polysaccharide as the major class. Dendrobium exerts various health effects on a variety of disease related to the digestive tract. Action mechanisms involve antioxidant, anti-inflammatory, anti-apoptotic, antioxidant, anticancer, alongside the regulation of some key signaling pathways.

CONCLUSION

Overall, Dendrobium appears as a promising TCM source of bioactives that has the potential to be further developed into nutraceuticals for digestive tract diseases compared to current drug treatments. This review highlights for Dendrobium potential effects with future perspectives for needed future research to maximize the use of bioactive compounds from Dendrobium for digestive tract disease treatment. A compile of Dendrobium bioactives is also presented alongside methods for their extraction and enrichment for potential incorporation in nutraceuticals.

Two previously undescribed phthalides from Talaromyces amestolkiae, a symbiotic fungus of Syngnathus acus

Amestolkins A (1) and B (2), two previously undescribed phthalides sharing the same planar structure of (1, 5-dihydroxyhexyl)-7-hydroxyisobenzofuran-1(3H)-one were isolated from Talaromyces amestolkiae. Their absolute configurations were elucidated by comprehensive analyses of spectroscopic evidences in high-resolution electrospray mass spectra (HRESIMS) and nuclear magnetic resonance (NMR) combined with electronic circular dichroism (ECD) and NMR calculations. 1 and 2 showed anti-neuroinflammatory activity by inhibiting the gene expressions of proinflammatory factors including C-C motif chemokine ligand 2 (CCL-2), tumor necrosis factor-α (TNF-α) and interleukin 6 (IL-6), as well as attenuating the excretion of inducible nitric oxide synthase (iNOS) in BV-2 microglial cells at the concentration of 30 μM.

Recent Research Progress on Natural Stilbenes in Dendrobium Species

Dendrobium is the second biggest genus in the Orchidaceae family, and many of them have been utilized as a traditional Chinese medicine (TCM) for thousands of years in China. In the last few decades, constituents with great chemical diversity were isolated from Dendrobium, and a wide range of biological activities were detected, either for crude extracts or for pure compounds. Stilbene compound is one of the primary active constituents in the genus Dendrobium. At present, 267 stilbene compounds with clarified molecular structures have been extracted and isolated from 52 species of Dendrobium, including 124 phenanthrenes and 143 bibenzyls. At the same time, activity studies have indicated that 157 compounds have pharmaceutical activity. Among them, most of the compounds showed antitumor activity, followed by antioxidant, anti-inflammatory and anti-α-glucosidase inhibitory activities. Additionally, 54 compounds have multiple pharmacological activities, such as confusarin (14), 2,4,7-trihydroxy-9,10-dihydro-phenanthrene (43), moscatilin (148), gigantol (150) and batatasin III (151). This review summarizes current knowledge about the chemical composition of stilbene, bioactivities and pharmacologic effects in 52 species of Dendrobium. We also expect to provide a reference for further research, development and utilization of stilbene constituents in the Dendrobium genus.

Picrotoxane sesquiterpenoids: chemistry, chemo- and bio-syntheses and biological activities

Covering: up to December 2021Picrotoxane sesquiterpenoids are a special category of natural products known to have a picrotoxane skeleton and are characterised by a highly oxidised cis-hydrindene core, lactone rings, and epoxide functionalities. Ever since the first picrotoxane was isolated from Menispermum cocculus in the early 19^th century, these compounds have long attracted the attention of natural product chemists, synthetic chemists, and pharmacologists for their particular structures and powerful biological activities. This review extensively summarizes a total of 132 naturally occurring picrotoxane sesquiterpenoids, taking into account their distributions, structural classifications, chemical and bio-synthetic researches, and bioactivities. It provides a comprehensive and in-depth perspective for further investigation on picrotoxane sesquiterpenoids.

Alkaloids from Dendrobium and their biosynthetic pathway, biological activity and total synthesis

BACKGROUND

Dendrobium Sw. has been used for thousands of years in China as a precious traditional Chinese medicine. It is derived from stems of various Dendrobium plants and has the functions of nourishing Yin and clearing heat, activating water and nourishing the stomach, moistening the lung and relieving cough. Modern phytochemical studies show that the main components of Dendrobium include alkaloids, polysaccharides, terpenoids, diphenylbenzene, and phenanthrene. Alkaloids are natural products with obvious biological activity and are important effective components of the medicinal activity or toxicity of plants. At present, dozens of alkaloids with various structures have been isolated from Dendrobium plants, and the alkaloid contents in Dendrobium plants of different species are quite different. From the perspective of food safety, the type, molecular structure, content and potential physiological activity or toxicity of alkaloids are important bases for evaluating the safety of edible plants. Studies have shown that the alkaloids isolated from Dendrobium have neuroprotective, anti-inflammatory and antitumor activities, showing that these alkaloids with potential medicinal activity are important sources of lead compounds in innovative drug development.

PURPOSE

To summarize the research progress on alkaloids in Dendrobium and provide a reference for research on the food safety and medicinal development of Dendrobium.

METHOD

Information about alkaloids from Dendrobium was collected from the scientific databases Web of Science, PubChem and PubMed. We discuss the biosynthetic pathway, biological activities and total synthesis of alkaloids from Dendrobium from 1964 to 2020 and summarize the knowledge of alkaloids from Dendrobium, the biosynthetic pathway, biological activities and total synthesis. We chose publications on their chemistry, drug effects, pharmacology, metabolism and biosynthesis, physiology and toxicity. Alkaloids, Dendrobium, biosynthetic pathway and biological activities were used as keywords to extract the relevant literature.

CONCLUSION

In this paper, the structural classification, biological activity, target and toxicology and synthesis of the alkaloids in Dendrobium were systematically reviewed, which will provide a reference for the safety, development and application of Dendrobium.

Hydroanthraquinones from Nigrospora sphaerica and Their Anti-inflammatory Activity Uncovered by Transcriptome Analysis

Transcriptome analysis is shown to be an effective strategy to understand the potential function of natural products. Here, it is reported that 11 previously undescribed hydroanthraquinones [nigroquinones A-K (1-11)], along with eight known congeners, were isolated from Nigrospora sphaerica. Their structures were elucidated by interpreting spectroscopic and spectrometric data including high-resolution mass spectra and nuclear magnetic resonance. The absolute configurations of 1-11 were confirmed by electronic circular dichroism calculations. Transcriptome analysis revealed that 3 (isolated in the largest amount) might be anti-inflammatory. Assays based on LPS-induced RAW264.7 macrophages and zebrafish embryos confirmed that some of the isolated hydroanthraquinones attenuated the secretion of pro-inflammatory mediators in vitro and in vivo. Further Western blotting and immunofluorescence experiments indicated that 4 (which showed the most obvious nitric oxide inhibition) could suppress the expression of nuclear factor-kappa-B (NF-κB), phosphorylation of the inhibitor of NF-κB kinase and inhibit the transportation of NF-κB to the nucleus. Hence, the suppression of the NF-κB signaling pathway may be responsible for the anti-inflammatory effect. These results show that bioactivity evaluation on the basis of transcriptome analysis may be effective in the functional exploration of natural products.

Glucosyloxybenzyl 2-isobutylmalates and phenolic glycosides from the flowers of Bletilla striata

Four previously undescribed compounds, including three glucosyloxybenzyl 2-isobutylmalates (1-3), one phenolic glycoside (4), along with ten known compounds were isolated from the flowers of Bletilla striata. The structures and absolute configurations of the undescribed compounds were elucidated on the basis of HR-ESIMS, NMR spectroscopy, optical rotation value, and acid hydrolysis experiment. Cytotoxicity of the isolated compounds against A549, HCT-116, and SW1990 cells and protective effects of t-BHP-induced L02 cytotoxic were assayed. The antioxidant activities of the isolated compounds were also evaluated.

Dihydrophenanthrenes and phenanthrenes from Dendrobium terminale

Two previously undescribed dihydrophenanthrene derivatives (1 and 2) were isolated along with twelve known analogues from the whole plant of Dendrobium terminale. The structures of the new compounds were elucidated on the basis of detailed spectroscopic analysis. The NMR data of known phenanthrene derivatives (7 and 9) were revised by 2D NMR. The isolated compounds were evaluated for cytotoxicity against three kinds of tumor cell lines (sw1990, HCT-116, and HepG2). Especially compounds 11 and 14 showed stronger antitumor effects, and the structure-activity relationship of these compounds was discussed.

Orchidaceae-Derived Anticancer Agents: A Review

Simple Summary

Orchids are commonly used in folk medicine for the treatment of infections and tumors but little is known about the actual chemical composition of these plants and their anticancer properties. In this paper, the most recent literature on orchid-derived bioactive substances with anticancer properties is reviewed. According to the published data, numerous species of orchids contain potential antitumor chemicals. Still, a relatively insignificant number of species of orchids have been tested for their bioactive properties and most of those studies were on Asian taxa. Broader research, ’including American and African species, as well as the correct identification of samples, is essential for evaluating the usefulness of orchids as a plant family with huge anticancer potential.

Abstract

Species of orchids, which belong to the largest family of flowering plants, are commonly used in folk medicine for the treatment of infections and tumors. However, little is known about the actual chemical composition of these plants and their anticancer properties. In this paper, the most recent literature on orchid-derived bioactive substances with anticancer properties is reviewed. For the assessment, previous papers on the anticancer activity of Orchidaceae published since 2015 were considered. The papers were found by exploring electronic databases. According to the available data, many species of orchids contain potential antitumor chemicals. The bioactive substances in a relatively insignificant number of orchids are identified, and most studies are on Asian taxa. Broader research on American and African species and the correct identification of samples included in the experiments are essential for evaluating the usefulness of orchids as a plant family with vast anticancer potential.

Analysis of Endophytic Bacterial Diversity From Different Dendrobium Stems and Discovery of an Endophyte Produced Dendrobine-Type Sesquiterpenoid Alkaloids

As the unique component of Dendrobium, dendrobine-type sesquiterpenoid alkaloids (DSAs) possess a variety of medicinal properties. It has been well documented that plant endophytes can in vitro synthesize secondary metabolites identical or similar to metabolites produced by their host plants. This study aimed to investigate the composition and distribution of endophytic bacteria of Dendrobium stems by Illumina MiSeq platform sequencing and cultivation-dependent methods and then to assess the potential for endophytic bacteria to produce DSAs. Results indicated that it was necessary to combine both cultivation-dependent and cultivation-independent methods to analyze the community structure of endophytic bacterial in plants comprehensively. The length of the Dendrobium stems influenced the endophytic bacterial community. The diversity and richness of endophytic bacteria in group J10_15cm of stems were the highest, which showed a significant difference from the other stem groups. However, there was no certain connection between the diversity and richness of endophytic bacteria and the content of dendrobine. It was most likely due to the influence of several specific endophytic bacteria genera, such as Sphingomonas and Rhodococcus. Athelia rolfsii, Myrothecium roridum, as pathogenic fungi, and Pectobacterium carotovorum subsp. actinidiae, as pathogenic bacteria of Dendrobium, were used to determine the antimicrobial activities. In these assays, six strains belonging to five genera showed antimicrobial activity against at least two phytopathogens. The strain BL-YJ10_15-29 (Paracoccus pueri THG-N2.35, 98.98%) showed the best antimicrobial activity against the three phytopathogens. In addition, 2 DSAs (6-hydroxydendrobine and nobilonine) were identified in the fermentation supernatant of the strain CM-YJ10_15-44 (Pseudomonas protegens CHA0, 99.24%), whereas the whole-genome analysis results further demonstrated that the precursors of the two DSAs [geranyl-PP and (E, E)-famesyl-PP] were synthesized mainly through the methyl-D-erythritol 4-phosphate pathway in this strain. This study provides new insight into the studies on the biosynthesis of DSAs and provides potential biocontrol bacteria.

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.

Aureonitol Analogues and Orsellinic Acid Esters Isolated from Chaetomium elatum and Their Antineuroinflammatory Activity

Overexpression of various pro-inflammatory factors in microglial cells tends to induce neurodegenerative diseases, for which there is no effective therapy available. Aureonitol (1) and seven analogues, including six previously undescribed [elatumenol A-F (2-4, 6-8, respectively)], along with two new orsellinic acid esters [elatumone A and B (9 and 10)], were isolated from Chaetomium elatum. The structures of the compounds were established through comprehensive analysis of spectroscopic data, including high-resolution mass spectra and one- and two-dimensional NMR, and absolute configurations determined by the Mosher method, dimolybdenum tetraacetate-induced circular dichroism, and theoretical calculations including electronic circular dichroism and NMR. Metabolites 3, 4, 7, and 8 exhibited antineuroinflammatory activity by attenuating the production of inflammatory mediators, such as nitric oxide, interleukin-6, interleukin-1β, tumor necrosis factor-α, and reactive oxygen species. Western blot results indicated 8 decreases the level of inducible nitric oxide synthase and cyclooxygenase-2 and suppresses the expression of Toll-like receptor 4 and nuclear factor kappa-B (NF-κB) as well as the phosphorylation of the inhibitor of NF-κB and p38 mitogen-activated protein kinases in lipopolysaccharide-activated BV-2 microglial cells.

Dendrobine-type alkaloids from Dendrobium nobile

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

A new triterpenoids from Nothotsuga longibracteata

A new lanostane triterpenoid (1) and two known (2, 3) analogues were isolated from Nothotsuga longibracteata. Their chemical structures were identified by spectral data including HR-ESI-MS, 1 D, and 2 D NMR. These lanostane triterpenoids showed no cytotoxic activities against three human tumour cell lines (A172, SHSY5Y, and Hela), but exhibited the activity of promoting the gastrointestinal motility of zebrafish treated with Nile red.

Three Previously Undescribed Chlorophenyl Glycosides from the Bulbs of Lilium regale

Three previously undescribed chlorophenyl glycosides, (2,4,6-trichloro-3-hydroxy-5-methoxyphenyl)methyl β-D-glucopyranoside (1), (2,4-dichloro-3,5-dimethoxyphenyl)methyl 6-O-β-D-glucopyranosyl-β-D-glucopyranoside (2) and 4-chloro-3-methoxy-5-methylphenyl 6-O-(6-deoxy-β-L-mannopyranosyl)-β-D-glucopyranoside (3) were obtained from Lilium regale. The absolute configurations of these new finds were elucidated by comprehensive analyses of spectroscopic data combined with acid hydrolysis derivatization. (2,4-dichloro-3,5-dimethoxyphenyl)methyl 6-O-β-D-glucopyranosyl-β-D-glucopyranoside (2) can inhibit the proliferation of lung carcinoma A549 cells with an IC₅₀ value of 29 μΜ.

Dendrobine suppresses endoplasmic reticulum stress-induced apoptosis through upregulating microRNA miR-381-3p to decrease caspase-4

Dendrobine has been reported to reduce blood lipid levels and apoptosis. The present study was designed to observe the effect of dendrobine in a model of ERS using vascular endothelial cells and to reveal the biological mechanisms and pathways responsible for the therapeutic effects of dendrobine on AS. Human umbilical vein endothelial cells (HUVECs) were pre-treated with various concentrations of dendrobine, followed by treatment with tunicamycin (TM) for the establishment of the cell models of ERS. The proliferation and apoptosis of HUVECs were detected by bromodeoxyuridine staining and flow cytometry, respectively. The target binding association was verified through dual luciferase reporter assay. It was found that TM treatment resulted in a low expression of miR-381-3p. Dendrobine treatment not only promoted the proliferation, but also inhibited the apoptosis of HUVECs induced by TM. The reduced expression of 78-kDa glucose-regulated protein, inositol-requiring enzyme 1, caspase-4, C/EBP homologous protein and caspase-3 was also observed following treatment with dendrobine. Dendrobine reduced the apoptosis of endothelial cells in the model of ERS by increasing miR-381-3p expression, and partially restored the cell proliferation level. This effect was significantly reduced after the expression of miR-381-3p was blocked. On the whole, the present study demonstrated that dendrobine upregulated miR-381-3p expression to inhibit apoptosis induced by ERS in HUVECs and this process was found to be mediated by caspase-4. The findings of the present study may provide new insight into the causes of endothelial cell apoptosis during AS and reveal the potent therapeutic effects of dendrobine in AS.

Chemical and Biological Profiles of Dendrobium in Two Different Species, Their Hybrid, and Gamma-Irradiated Mutant Lines of the Hybrid Based on LC-QToF MS and Cytotoxicity Analysis

The Dendrobium species (Orchidaceae) has been cultivated as an ornamental plant as well as used in traditional medicines. In this study, the chemical profiles of Dendrobii Herba, used as herbal medicine, Dendrobium in two different species, their hybrid, and the gamma-irradiated mutant lines of the hybrid, were systematically investigated via ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-QToF MS). Among the numerous peaks detected, 17 peaks were unambiguously identified. Gigantol (1), (1R,2R)-1,7-hydroxy-2,8-methoxy-2,3-dihydrophenanthrene-4(1H)-one (2), tristin (3), (−)-syringaresinol (4), lusianthridin (5), 2,7-dihydroxy-phenanthrene-1,4-dione (6), densiflorol B (7), denthyrsinin (8), moscatilin (9), lusianthridin dimer (10), batatasin III (11), ephemeranthol A (12), thunalbene (13), dehydroorchinol (14), dendrobine (15), shihunine (16), and 1,5,7-trimethoxy-2-phenanthrenol (17), were detected in Dendrobii Herba, while 1, 2, and 16 were detected in D. candidum, 1, 11, and 16 in D. nobile, and 1, 2, and 16 in the hybrid, D. nobile × candidum. The methanol extract taken of them was also examined for cytotoxicity against FaDu human hypopharynx squamous carcinoma cells, where Dendrobii Herba showed the greatest cytotoxicity. In the untargeted metabolite analysis of 436 mutant lines of the hybrid, using UPLC-QToF MS and cytotoxicity measurements combined with multivariate analysis, two tentative flavonoids (M1 and M2) were evaluated as key markers among the analyzed metabolites, contributing to the distinction between active and inactive mutant lines.

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.

Flavonoids with Inhibitory Effects on NLRP3 Inflammasome Activation from Millettia velutina

Eight new flavonoids, including two β-hydroxy/methoxychalcones, velutones A and B (1 and 2), two 1,3-diarylpropan-1-ols, velutols C and D (3 and 4), a dihydroxychalcone, velutone E (5), a chalcone, velutone F (6), a furanoflavanone, velutone G (7), and a furanoflavonol, velutone H (8), and 14 known compounds were isolated from Millettia velutina. Their structures were determined by high-resolution electrospray ionisation mass spectrometry (HR-ESIMS) and spectroscopic data analyses and time-dependent density functional theory electronic circular dichroism (TD-DFT-ECD) calculations. Among the isolated constituents, compound 6 exhibited the most potent inhibitory effect (IC₅₀: 1.3 μM) against nigericin-induced IL-1β release in THP-1 cells. The initial mechanism of action study revealed that compound 6 suppressed NLRP3 inflammasome activation via blocking ASC oligomerization without affecting the priming step, which subsequently inhibited caspase-1 activation and IL-1β secretion. Most importantly, compound 6 exerted potent protective effects in the LPS-induced septic shock mice model by improving the survival rate of mice and suppressing serum IL-1β release. These results demonstrated that compound 6 had the potential to be developed as a broad-spectrum NLRP3 inflammasome inhibitor for the treatment of NLRP3-related disease.