Eight new eudesmane- and eremophilane-type sesquiterpenoids from Atractylodes lancea

Ligulariatinside A, a new sesquiterpene glycoside from roots of Ligularia veitchiana

A new sesquiterpene glycoside, ligulariatinside A (1), along with nine known compounds, dibutyl phthalate (2), 1-O-(9Z,12Z-octadecadienoyl) glycerol (3), bis (2-ethylhexyl) phthalate (4), 4-hydroxy-3-methoxyphenylpropanol (5), dihydrosyringenin (6), caffeic acid (7), 6β-hydroxy-7(11)-eremophilen-12,8α-olide (8), together with the mixture of 6β,8β-dihydroxyeremophil-7(11)-en-12,8α-olide (9) and 6β,8α-dihydroxy-eremophil-7(11)-en-12,8β-olide (10) were isolated from roots of L. veitchiana. Structures of these compounds were elucidated by comprehensive analyses of HRESIMS, 1D NMR, and 2D NMR spectroscopic data. Compounds 2 and 4 are not likely natural compounds but contaminants. All isolated compounds were tested for antibacterial activity. Compounds 1, 5, 6, together with the mixture of 9 and 10, showed mild activity against Vibrio anguillarum, with MIC values of 50, 50, 100, and 200 μg/mL, while compound 7 showed moderate activity against Vibrio anguillarum, with a MIC value of 25 μg/mL.

Bioassay-guided isolation of antibacterial and anti-inflammatory components from Atractylodes lancea

A bioassay-guided isolation from Atractylodes lancea (Thunb.) DC. obtained 22 compounds, including eight previously undescribed sesquiterpenoids and polyacetylenes (1, 3 and 12-17), as well as fourteen known analogues, and their structures were confirmed by extensive spectroscopic methods. This study evaluated their antibacterial activity against methicillin resistant Staphylococcus aureus (MRSA) for the first time, as well as anti-inflammatory activity. Most of them, including new compounds, showed varying degrees of antibacterial activity against S. aureus and MRSA. Notably, compound 21 exhibited significant antibacterial activity against four different bacteria (MIC 6.25-20.00 μg/mL). This suggested that 21 may have the potential to be developed into a broad-spectrum antibacterial agent. Moreover, except for 9 and 11, most compounds exhibited great anti-inflammatory activity (IC50 1.92-37.91 μM), and iNOS might be a potential target of these compounds according to the molecular docking analysis.

Eudesmane-type sesquiterpenoids: Structural diversity and biological activity

Sesquiterpenoids are integral constituents of terpenoid-bearing plants, comprising a diverse and abundant class of natural compounds, among which eudesmane-type sesquiterpenoids have bicyclic structures that feature the fusion of two six-membered carbon rings, thereby attracting considerable attention. They are widespread in nature, with multifaceted biological activities such as anti-inflammatory, anticancer, antimicrobial, antimalarial, and insecticidal activities, thus gaining focus in life science research. The discovery and identification of these active compounds have laid a foundation for unraveling their potential medicinal value. In this review, we comprehensively explore the natural eudesmane-type sesquiterpenoids isolated (totaling 391 compounds) between 2016 and 2022, elucidating their chemical structures, plant distribution patterns, and pertinent biological properties. Accordingly, the study serves not only as a framework for researchers to thoroughly comprehend these compounds but also as a robust reference for future endeavors aimed at exploring the pharmaceutical potential and prospective applications of these molecules.

Predictive Analysis of Quality Markers of Atractylodis Rhizoma Based on Fingerprint and Network Pharmacology

BACKGROUND

Atractylodes chinensis (DC.) Koidz. (A. chinensis) is a perennial herbaceous plant that is widely used as a Chinese medicine herb for gastric diseases. However, the bioactive compounds of this herbal medicine have not been defined, and quality control is imperfect.

OBJECTIVE

Although the method of quality evaluation method for A. chinensis by high-performance liquid chromatography (HPLC) fingerprinting has been reported in related papers, it remains unknown whether the chemical markers selected are representative of their clinical efficacy. To develop methods for qualitative analysis and improved quality evaluation of A. chinensis.

METHOD

In this study, HPLC was used to establish fingerprints and conduct similarity evaluation. Principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) were used to reveal the differences of these fingerprints. Network pharmacology was used to analyze the corresponding targets of the active ingredients. Meantime, an active ingredient-target-pathway network was constructed to investigate the characteristics of the medical efficacy of A. chinensis and to predict potential Q-markers.

RESULTS

Combining network pharmacological effectiveness and composition specificity with the Q-marker concept, atractylodin (ATD), β-eudesmol, atractylenolide Ι (AT-I) and atractylenolide III (AT-III) were predicted to be potential Q-markers of A. chinensis that showed anti-inflammatory, antidepressant, anti-gastric, and antiviral effects by acting on 10 core targets and 20 key pathways.

CONCLUSIONS

The HPLC fingerprinting method established in this study is straightforward, and the identified four active constituents can be used as Q-markers of A. chinensis. These findings facilitate effective quality evaluation of A. chinensis and suggest this approach could be applied to evaluate the quality of other herbal medicines.

HIGHLIGHTS

The fingerprints of Atractylodis rhizoma were organically combined with network pharmacology to further clarify its criteria for quality control.

Ten undescribed eremophilane and guaiane sesquiterpenes from Penicillium roqueforti

Nine undescribed eremophilane sesquiterpenes, one undescribed guaiane sesquiterpene, along with ten known analogues were isolated and identified from fungus Penicillium roqueforti, which was separated from the root soil of Hypericum beanii N. Robson collected from the Shennongjia Forestry District, Hubei Province. Their structures were elucidated on the basis of various spectroscopic analyses, mainly including NMR and HRESIMS data, ¹³C NMR calculation with DP4+ probability analyses, ECD calculations, and single-crystal X-ray diffraction experiments. Furthermore, all twenty compounds were evaluated for the in vitro cytotoxic activities against seven human tumor cell lines, and the result suggested that 14-hydroxymethylene-1(10)-ene-epi-guaidiol A exhibited considerable cytotoxic activity against the Farage (IC₅₀ < 10 μM, 48 h), SU-DHL-2, and HL-60 cells. Further mechanism study demonstrated that 14-hydroxymethylene-1(10)-ene-epi-guaidiol A could significantly promote apoptosis by inhibiting tumor cell respiration and decreasing intracellular ROS levels, thereby inducing S-phase blockade in tumor cells.

Germacrane-type sesquiterpenoids from the flowers of Chrysanthemum indicum with hepatoprotective activity

Two new germacrane-type sesquiterpenoids, chrysanthemolides A (1) and B (2), and four known germacrane-type sesquiterpenoids, hanphyllin (3), 3β-hydroxy-11α,13-dihydro-costunolide (4), costunolide (5), and 6,7-dimethylmethylene-4-aldehyde-1β-hydroxy-10(15)-ene-(4Z)-dicyclodecylene (6), were isolated and identified from the flowers of Chrysanthemum indicum. The structures of the new compounds were elucidated via high resolution electrospray ionization mass spectrometry (HR-ESI-MS), 1D and 2D nuclear magnetic resonance (NMR) spectra and electronic circular dichroism (ECD). Meanwhile, all the isolates were tested for their hepatoprotective activity in tert-butyl hydroperoxide (t-BHP) injured AML12 cells. Compounds 1, 2, and 4 showed significant protective effects at 40 μM, comparable with the positive control resveratrol at 10 μM. As the most potent one, compound 1 was chosen for further studies. Compound 1 dose-dependently increased the viability of t-BHP-injured AML12 cells. Furthermore, compound 1 decreased reactive oxygen species accumulation, while increased glutathione level, heme oxygenase-1 level and superoxide dismutase activity, through anchoring in the binding site of Kelch domain of the Kelch-like ECH-associated protein 1 (Keap1) to promote the dissociation of nuclear factor erythroid 2-related factor 2 from Keap1 and translocation to nuclei. In summary, germacrane-type sesquiterpenoids from C. indicum might be further developed to protect liver against oxidative damage.

In Vitro and In Silico Investigation of Polyacetylenes from Launaea capitata (Spreng.) Dandy as Potential COX-2, 5-LOX, and BchE Inhibitors

Diverse secondary metabolites are biosynthesized by plants via various enzymatic cascades. These have the capacity to interact with various human receptors, particularly enzymes implicated in the etiology of several diseases. The n-hexane fraction of the whole plant extract of the wild edible plant, Launaea capitata (Spreng.) Dandy was purified by column chromatography. Five polyacetylene derivatives were identified, including (3S,8E)-deca-8-en-4,6-diyne-1,3-diol (1A), (3S)-deca-4,6,8-triyne-1,3-diol (1B), (3S)-(6E,12E)-tetradecadiene-8,10-diyne-1,3-diol (2), bidensyneoside (3), and (3S)-(6E,12E)-tetradecadiene-8,10-diyne-1-ol-3-O-β-D-glucopyranoside (4). These compounds were investigated for their in vitro inhibitory activity against enzymes involved in neuroinflammatory disorders, including cyclooxygenase-2 (COX-2), 5-lipoxygenase (5-LOX), and butyrylcholinesterase (BchE) enzymes. All isolates recorded weak-moderate activities against COX-2. However, the polyacetylene glycoside (4) showed dual inhibition against BchE (IC₅₀ 14.77 ± 1.55 μM) and 5-LOX (IC₅₀ 34.59 ± 4.26 μM). Molecular docking experiments were conducted to explain these results, which showed that compound 4 exhibited greater binding affinity to 5-LOX (-8.132 kcal/mol) compared to the cocrystallized ligand (-6.218 kcal/mol). Similarly, 4 showed a good binding affinity to BchE (-7.305 kcal/mol), which was comparable to the cocrystallized ligand (-8.049 kcal/mol). Simultaneous docking was used to study the combinatorial affinity of the unresolved mixture 1A/1B to the active sites of the tested enzymes. Generally, the individual molecules showed lower docking scores against all the investigated targets compared to their combination, which was consistent with the in vitro results. This study demonstrated that the presence of a sugar moiety (in 3 and 4) resulted in dual inhibition of 5-LOX and BchE enzymes compared to their free polyacetylenes analogs. Thus, polyacetylene glycosides could be suggested as potential leads for developing new inhibitors against the enzymes involved in neuroinflammation.

Anti-Inflammatory Activities of Monoterpene and Sesquiterpene Glycosides from the Aqueous Extract of Artemisia annua L

Artemisia annua L. is a Chinese medicinal herb, but the origin of its pharmacological properties, including its anti-inflammatory activity, remain unknown. In this study, five new monoterpene glycosides (1-5) and two new sesquiterpene glycosides (6 and 7) were isolated from the aqueous extract of the aerial parts of A. annua. The structures of these glycosides were determined using high-resolution electrospray ionization mass spectrometry, nuclear magnetic resonance spectroscopy, electronic circular dichroism calculations, and chemical hydrolysis methods. The anti-inflammatory activities of the isolated compounds were evaluated by down-regulating interleukin-6 (IL-6) in lipopolysaccharide-stimulated RAW 264.7 macrophages. Notably, all the new compounds significantly inhibited the expression of IL-6 in a dose-dependent manner.

Full-length transcriptome analysis of two chemotype and functional characterization of genes related to sesquiterpene biosynthesis in Atractylodes lancea

Atractylodes lancea (Thunb.) DC. is an important medicinal plant mainly distributed in China. A. lancea is rich in volatile oils and has a significant effect on various diseases, including coronavirus disease 2019 (COVID-19). Based on the signature constituents of volatile oils, A. lancea is divided into two chemotypes: the Dabieshan and Maoshan chemotype. Gas chromatography-mass spectrometry (GC-MS) results revealed that the hinesol and β-eudesmol contents in the Dabieshan chemotype were higher than those in the Maoshan chemotype. Next-generation sequencing (NGS) and single-molecule real-time (SMRT) sequencing technologies were combined to investigate the molecular mechanisms of sesquiterpenoid biosynthesis in A. lancea. A total of 42 differentially expressed genes (DEGs) for terpenoid biosynthesis were identified in the two chemotype groups, and nine full-length terpene synthase (TPS) genes were identified. Subcellular localization revealed that AlTPS1 and AlTPS2 proteins were localized in the nucleus and endoplasmic reticulum. They use FPP as a substrate to generate sesquiterpenoids. AlTPS1 catalyzes biosynthesis of elemol while AlTPS2 is observed to perform β-farnesene synthase activity. This study provides information for understanding the differences in the accumulation of terpenoids in two chemotypes of A. lancea and lays a foundation for further elucidation of the molecular mechanism of sesquiterpenoid biosynthesis.

Sesquiterpenoids Isolated from the Rhizomes of Genus Atractylodes

Atractylodes plants have been used in traditional herbal medicine to treat gastrointestinal diseases and contain various chemical compounds. Sesquiterpenoids are the most important therapeutic compounds in Atractylodes rhizomes. Based on studies reported from 2000 to 2022, we classified sesquiterpenoids by their chemical skeletons and original resources. Moreover, we discussed their biosynthesis and physicochemical and pharmacological features. We reported sesquiterpenoids with skeletal moieties, such as monocyclic sesquiterpenes (bisabolene- and elemene-type), bicyclic sesquiterpenes (eudesmane-, isopterocarpolone-, hydroxycarissone-, eremophilane-, bisesquiterpenoid-, guaiane- and spirovetivane-type and eudesmane lactones) and tricyclic sesquiterpenes (cyperene- and patchoulene-type), with their biosynthetic pathways, chemical modifications and in vivo metabolites. The pharmacological activities of sesquiterpenoids as anti-inflammatory, anti-tumor, anti-diabetic and anti-microbial and for treating gastrointestinal disorders have been reported for this genus.

Two Novel Sesquiterpenoid Glycosides from the Rhizomes of Atractylodes lancea

Secoatractylohexone A (1), an unprecedented secoguaiane lactone glycoside featuring 6/7 cores and dihydroxy-9-guaine-3-one 11-O-β-d-glucopyranoside (2), a 9,10-unsaturated guaiene-type glycoside possessing an uncommon scaffold, were isolated from the water-soluble portion of the ethanolic extract of Atractylodes lancea rhizomes together with five known compounds (3–7). The structures of 1 and 2 were elucidated on the basis of extensive spectroscopic data and application of the CD technique. The potential biological activities of secoatractylohexone A were predicted by network pharmacology in silico, the result of which indicated that secoatractylohexone A may be used to treat type II diabetes.

Comparative analysis in different organs and tissue-specific metabolite profiling of Atractylodes lancea from four regions by GC-MS and laser microdissection

Traditional Chinese medicine is made from the rhizome of Atractylodes lancea (Thunb.) DC. (Compositae), known as Cangzhu. In this study, gas chromatography-mass spectrometry was used to identify and quantify the volatile oils of different organs of A. lancea from four regions of China: Jiangsu, Anhui, Henan, and Hubei provinces. The volatile oils of A. lancea were qualitatively and quantitatively characterized using gas chromatography-mass spectrometry combined with laser microdissection. The results identified 21 components in A. lancea, the majority of the components were found in the rhizomes, followed by the fibrous roots, flowers, leaves, and stems. According to the contents of volatile oils in A. lancea, it was divided into Dabieshan (mainly includes hinesol and β-eudesmol) and Maoshan types (mainly includes atractylon and atractylodin), and the ratios of hinesol:β-eudesmol:atractylon:atractylodin were 17.06:4.55:0:1, 12.66:11.71:0.99:1, 7.43:6.23:0:1, and 0.13:0.16:1.52:1 in A. lancea from AH, HN, HB, and JS, respectively. Tissue-specific study indicated that Dabieshan type mainly includes elemol, hinesol, and β-eudesmol in the periderm and secretory cavities of A. lancea, whereas Maoshan type mainly includes atractylon, atractylodin, little hinesol, and β-eudesmol in the secretory cavities. Conversely, no volatile oils were detected in the cortex, phloem, xylem, vascular ray, or pith. This study provides a foundation for further evaluation and utilization of A. lancea.

Molecular cloning and biochemical characterization of a new coumarin glycosyltransferase CtUGT1 from Cistanche tubulosa

UDP-glycosyltransferases (UGTs) are an important and functionally diverse family of enzymes involved in secondary metabolite biosynthesis. Coumarin is one of the most common skeletons of natural products with candidate pharmacological activities. However, to date, many reported GTs from plants mainly recognized flavonoids as sugar acceptors. Only limited GTs could catalyze the glycosylation of coumarins. In this study, a new UGT was cloned from Cistanche tubulosa, a valuable traditional tonic Chinese herb, which is abundant with diverse glycosides such as phenylethanoid glycosides, lignan glycosides, and iridoid glycosides. Sequence alignment and phylogenetic analysis showed that CtUGT1 is phylogenetically distant from most of the reported flavonoid UGTs and adjacent to phenylpropanoid UGTs. Extensive in vitro enzyme assays found that although CtUGT1 was not involved in the biosynthesis of bioactive glycosides in C. tubulosa, it could catalyze the glucosylation of coumarins umbelliferone 1, esculetine 2, and hymecromone 3 in considerable yield. The glycosylated products were identified by comparison with the reference standards or NMR spectroscopy, and the results indicated that CtUGT1 can regiospecifically catalyze the glucosylation of hydroxyl coumarins at the C7-OH position. The key residues that determined CtUGT1's activity were further discussed based on homology modeling and molecular docking analyses. Combined with site-directed mutagenesis results, it was found that H19 played an irreplaceable role as the crucial catalysis basis. CtUGT1 could be used in the enzymatic preparation of bioactive coumarin glycosides.

New sesquiterpenoid glycoside from the rhizomes of Atractylodes lancea

Six sesquiterpenoids and four lignans (1-10) were isolated from the n-BuOH extract of the rhizomes of Atractylodes lancea. Among them, the new sesquiterpenoid glycoside named (4 R, 5S, 7R)-hinesolone-11-O-β-ᴅ-glucopyranoside (1), along with three known compounds (2-4) were first obtained from this genus. All the isolates were elucidated by spectroscopic analyses and chemical methods, and the absolute configurations were assigned by electronic circular dichroism spectroscopy technique. In addition, the cytotoxic bioassay of compound 1 was evaluated and results showed it had no significant antitumor activity against human cancer cell lines MCF-7, HepG-2 and Hela.