Phytochemistry and Pharmacology of Sesquiterpenoids from Atractylodes DC. Genus Rhizomes.

The rhizomes of the genus Atractylodes DC. consist of various bioactive components, including sesquiterpenes, which have attracted a great deal of research interest in recent years. In the present study, we reviewed the previously published literatures prior to November 2023 on the chemical structures, biosynthetic pathways, and pharmacological activities of the sesquiterpenoids from this genus via online databases such as Web of Science, Google Scholar, and ScienceDirect. Phytochemical studies have led to the identification of more than 160 sesquiterpenes, notably eudesmane-type sesquiterpenes. Many pharmacological activities have been demonstrated, particularly anticancer, anti-inflammatory, and antibacterial and antiviral activities. This review presents updated, comprehensive and categorized information on the phytochemistry and pharmacology of sesquiterpenes in Atractylodes DC., with the aim of offering guidance for the future exploitation and utilization of active ingredients in this genus.

Eudesmane sesquiterpenoids with inhibitory effects on NO production from Artemisia princeps.

Five undescribed eudesmane methyl esters (1-5), three undescribed eudesmane-12,6-olides (6-8), and 21 known analogues (9-29) were isolated from the aerial part of Artemisia princeps Pamp. Their structures were established by detailed analysis of the NMR and HRESIMS data. The absolute configurations of 1-8 were determined based on single-crystal X-ray diffraction analysis and ECD calculations. Moreover, the inhibitory effects on LPS-induced NO production in BV-2 microglial cells of all the isolated compounds were assessed. Except for compounds 2, 4, 10, and 11, the others showed significant inhibitory activities, with IC50 values of 0.73-18.66 µM, wherein the potential structure-activity relationship was also discussed.

Eudesmane-type sesquiterpenoids from the aerial parts of Artemisia lavandulaefolia and their anti-pancreatic cancer activities.

Five undescribed eudesmane sesquiterpenoids, artemilavanins A-E, and one undescribed rearranged eudesmane sesquiterpenoid, artemilavanin F, were isolated from the 95% ethanol extract of the aerial parts of Artemisia lavandulaefolia DC., along with ten known compounds. The structures and configurations of undescribed compounds were mainly elucidated by spectroscopic analyses and single-crystal X-ray diffraction analysis. Among all isolated compounds, artemilavanin F exhibited inhibitory activity on PANC-1 pancreatic cancer cells with IC50 of 9.69 ± 2.39 µM. Artemilavanin F inhibited PANC-1 cell proliferation by induction of G2/M cell cycle arrest and apoptosis mediated by downregulation of cyclin-dependent kinases and accumulation of reactive oxygen species. Moreover, artemilavanin F inhibited the colony formation, cell migration and sphere formation of PANC-1 cells, indicating the suppression of stem-cell-like phenotype of PANC-1 cells. Further results confirmed that the expression of cancer stem cell markers such as Bmi1, CD44, CD133 were inhibited by artemilavanin F. Downregulation of epithelial-mesenchymal transition (EMT) markers such as N-cadherin and Oct-4 indicated the potential of artemilavanin F in prevention of metastasis.

Sesquiterpene Lactones with Astrodaucane Skeleton from Astrodaucus orientalis.

Four sesquiterpene lactones, astrodaucanolide A - D (1: -4: ) with unique structures, toghether with two known phenylpropanoid esters (5: and 6: ) were isolated from a flower extract of Astrodaucus orientalis. The structures were established by 1D and 2D NMR spectroscopy and high-resolution mass spectrometry (HRESIMS), and the absolute configuration of 1: -4: was determined by electronic circular dichroism (ECD). Compounds 1: -4: novel architecture represents a new class of sesquiterpenes with new skeleton. A putative biosynthetic pathway for their scaffold is proposed with a germacryl cation as the precursor. The suggested biosynthesis pathway is similar to that of eudesmane sesquiterpenes with a different direction of protonation which then leads to the new skeleton, named astrodaucane by the 1,2-methyl migration.

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.

Anti-inflammatory and PTP1B inhibitory sesquiterpenoids from the twigs and leaves of Aglaia lawii.

Twelve sesquiterpenoids with seven different carbon skeletons, including four isodaucanes (1-4), an aromadendrane (5), a guaiane (6), a cadalane (7), two eudesmanes (8 and 9), two bisabolanes (10 and 11), and a megastigmane (12), were isolated from the twigs and leaves of Aglaia lawii (Wight) C. J. Saldanha et Ramamorthy. Of these compounds, amouanglienoids A (1) and B (2) are new isodaucane sesquiterpenoids. This is the first report of isodaucanes from the genus Aglaia, and amouanglienoid A (1) represents the first isodaucane containing a Δ7(8) double bond. Their structures were discerned from extensive spectroscopic analyses, single-crystal X-ray diffraction, and comparison of the experimental and calculated ECD data. In in vitro bioassays, compounds 1, 10, and 11 showed potent inhibitory effects against lipopolysaccharide (LPS)-induced inflammation in BV-2 microglial cells, while compound 11 exhibited considerable inhibition of PTP1B with an IC50 value of 16.05 ± 1.09 µM.

Bioassay-Guided Isolation of Two Eudesmane Sesquiterpenes from Lindera strychnifolia Using Centrifugal Partition Chromatography.

In this study, a centrifugal partition chromatography (CPC) separation was applied to identify antioxidant-responsive element (ARE) induction molecules from the crude extract of Lindera strychnifolia roots. CPC was operated with a two-phase solvent system composed of n-hexane-methanol-water (10:8.5:1.5, v/v/v) in dual mode (descending to ascending), which provided a high recovery rate (>95.5%) with high resolution. Then, ARE induction activity of obtained CPC fractions was examined in ARE-transfected HepG2 cells according to the weight ratios of the obtained fractions. The fraction exhibiting ARE-inducing activity was further purified by preparative HPLC that led to isolation of two eudesmane type sesquiterpenes as active compounds. The chemical structures were elucidated as linderolide U (1) and a new sesquiterpene named as linderolide V (2) by spectroscopic data. Further bioactivity test demonstrated that compounds 1 and 2 enhanced ARE activity by 22.4-fold and 7.6-fold, respectively, at 100 µM concentration while 5 µM of sulforaphane induced ARE activity 24.8-fold compared to the control.

Eudesmane and Eremophilane Sesquiterpenes from the Fruits of Alpinia oxyphylla with Protective Effects against Oxidative Stress in Adipose-Derived Mesenchymal Stem Cells.

Alpinia oxyphylla Miquel (Zingiberaceae) has been reported to show antioxidant, anti-inflammatory, and neuroprotective effects. In this study, two new eudesmane sesquiterpenes, 7α-hydroperoxy eudesma-3,11-diene-2-one (1) and 7ß-hydroperoxy eudesma-3,11-diene-2-one (2), and a new eremophilane sesquiterpene, 3α-hydroxynootkatone (3), were isolated from the MeOH extract of dried fruits of A. oxyphylla along with eleven known sesquiterpenes (4-14). The structures were elucidated by the analysis of 1D/2D NMR, high-resolution electrospray ionization mass spectrometry (HRESIMS), and optical rotation data. Compounds (1-3, 5-14) were evaluated for their protective effects against tert-butyl hydroperoxide (tBHP)-induced oxidative stress in adipose-derived mesenchymal stem cells (ADMSCs). As a result, treatment with isolated compounds, especially compounds 11 and 12, effectively reverted the damage of tBHP on ADMSCs in a dose-dependent manner. In particular, 11 and 12 at 50 µM improved the viability of tBHP-toxified ADMSCs by 1.69 ± 0.05-fold and 1.61 ± 0.03-fold, respectively.

Therapeutic potential and pharmacological activities of ß-eudesmol.

Herbal medicines are attracting the attention of researchers worldwide. ß-Eudesmol is one of the most studied and major bioactive sesquiterpenes, mainly extracted from Atractylodes lancea (Thunb) DC. rhizomes. It has potential anti-tumor and anti-angiogenic activities and is an inhibitor of tumor growth by inhibiting angiogenesis by suppressing CREB activation of the growth factor signaling pathway. It also stimulates neurite outgrowth in rat pheochromocytoma cells with activation of mitogen-activated protein kinases. It may be a promising lead compound for enhancing neural function, and it may help to explain the underlying mechanisms of neural differentiation. In this review, we summarized the currently available clinical and preclinical studies describing the therapeutic applications of ß-eudesmol.

Three new sesquiterpenoids with cytotoxic activity from Artemisia argyi.

A new eudesmane sesquiterpenoid, artemisargin A (1), two new guaianolide sesquiterpenoids, artemisargins B (2) and C (3), along with three known sesquiterpenoids (4-6), were isolated from the leaves of Artemisia argyi. Their structures were determined by extensive spectroscopic methods and electronic circular dichroism calculations. Biological evaluation showed that 1 could inhibit the growth of cancer cells, especially in BGC-823 cells with an IC50 value of 49.87 µM.

Simultaneous determination of asarinin, ß-eudesmol, and wogonin in rats using ultraperformance liquid chromatography-tandem mass spectrometry and its application to pharmacokinetic studies following administration of standards and Gumiganghwal-tang.

Asarinin, ß-eudesmol, and wogonin have common antiangiogenic activities and have the potential for use in chemotherapy. Besides, they are multivalent substances that are combined in various herbal medicines. The purpose of this study was to develop a method for simultaneous analysis of asarinin, ß-eudesmol, and wogonin, which are representative pharmacological components of Asarum heterotropoides, Atractylodes lancea, and Scutellaria baicalensis, respectively, in rat biosamples using ultraperformance liquid chromatography-tandem mass spectrometry. The three components were separated using 5 mm aqueous ammonium acetate containing 0.1% formic acid and acetonitrile as a mobile phase, equipped with a KINETEX core-shell C18 column. The analysis was quantitated on a triple-quadrupole mass-spectrometer employing electrospray ionization, and operated in the multiple reaction monitoring mode. The chromatograms showed high resolution, sensitivity, and selectivity with no interference with plasma, urine, and feces constituents. The developed analytical method satisfied international guidance criteria and could be successfully applied to the pharmacokinetic (PK) studies evaluating oral bioavailability of asarinin, ß-eudesmol, and wogonin after oral and intravenous administration and their urinary and fecal excretion ratios after oral administration to rats. Furthermore, the analysis was extended to PK studies following oral administration of Gumiganghwal-tang. This study was the first simultaneous analysis of the aforesaid three constituents in rat plasma, urine, and feces that also determined their PK parameters.

Oxygenated Geosmins and Plant-like Eudesmanes from a Bacterial Mangrove Endophyte.

Geosmin (1) is a microbial terpene metabolite that is responsible for the typical smell of soil and causes an off-odor of food and water. Eudesmane sesquiterpenes are commonly found in plant essential oils. Here we describe the discovery of four geosmin-type metabolites, 7R-hydroxygeosmin (2), 3-oxogeosmin (3), 2R-hydroxy-7-oxogeosmin (4), 5-deoxy-7ß,9ß-dihydroxygeosmin (5), the plant-like eudesmanes 4ß,10α-eudesmane-5ß,11-diol (6) and (1S,5S,6S,7S,10S)-10α-eudesm-4(15)-ene-1α,6α-diol (7), and the known 1(10)E,5E-germacradiene-2,11-diol (8) from a bacterial endophyte (Streptomyces sp. JMRC:ST027706) of the mangrove plant Bruguiera gymnorrhiza. By means of NMR, MS, and ECD spectroscopy, all chemical structures as well as the absolute configurations for the new compounds were elucidated. Compounds 2-5 represent the first geosmin-related metabolites directly as bacterial natural products. The plant-derived eudesmane-5ß,11-diol (6) and (1S,5S,6S,7S,10S)-10α-eudesm-4(15)-ene-1α,6α-diol (7) are also now reported as bacterial products. The broad antimicrobial activities of 6 against a suite of fungal and bacterial pathogens including methicillin-resistant Staphylococcus aureus suggest that this terpene could be an important active principle of the medicinal plant Cymbopogon distans. The discovery of geosmin metabolites from one actinomycete indicated that these bacteria could possess enzymes for modifying geosmin and offer a possibility for bioremediation.

Nitric Oxide Production Inhibitory Eudesmane-Type Sesquiterpenoids from Artemisia argyi.

Six new eudesmane-type sesquiterpene derivatives, artemargyinins A-F were isolated from the leaves of Artemisia argyi. Their structures were elucidated based on the extensive analysis of spectroscopic data. Artemargyinins A-F feature a lactone ring-opening eudesmane-type sesquiterpene with an isoprenoid group at C(8). All compounds were tested for their inhibitory effects on lipopolysaccharide-induced nitric oxide (NO) production in RAW264.7 macrophages. Artemargyinins A-F showed more potent NO production inhibitory activity with IC50 values ranging from 7.66±0.53 to 61.19±2.54 µM than the positive control quercetin (IC50 =74.34±1.39 µM). Among them, artemargyinins C and D exhibited strong inhibitory activity with IC50 values of 8.08±0.21 and 7.66±0.53 µM, respectively.

Antimalarial Eudesmane Sesquiterpenoids from Dobinea delavayi.

Eleven new angeloylated eudesmane sesquiterpenoids, dobinins D-N (2, 3, 5, 6, 8, 9, and 11-15), and four known compounds (1, 4, 7, and 10) were isolated from the roots of Dobinea delavayi. A new oxidation product (8a) was also obtained from dobinin H (8). Their structures were elucidated by spectroscopic data and single-crystal X-ray diffraction analyses. Dobinins K-N (12-15) are the first examples of rearrangement noreudesmane analogue sesquiterpenoids with a unique 6/5-fused carbon skeleton. A putative biosynthetic pathway of compounds 12-15 is proposed. Compound 12 exhibited significant antimalarial activity superior to artemisinin with the inhibition ratio of 59.1%, and compounds 3, 5, and 15 exhibited moderate antimalarial activities against Plasmodium yoelii BY265RFP with inhibition ratios ranging from 14.5% to 18.5% at a dose of 30 mg/kg/day. In addition, the apoptosis of P. yoelii BY265RFP by the depolarization of mitochondrial membrane potential with striking ROS production, after parasitized erythrocyte lysis mediated by cytokines IL-12 and IFN-γ, may be a possible mechanism of antimalarial action of compound 12 against P. yoelii BY265RFP.

Eudesmane-type sesquiterpene glycosides: sonneratiosides A-E and eudesmol ß-D-glucopyranoside from the leaves of Sonneratia alba.

Five eudesmane-type sesquiterpene glycosides, named sonneratiosides A-E (1-5), were isolated from the leaves of Sonneratia alba (Lythraceae). The aglycone of sonneratioside A was identified as cryptomeridiol also known as proximadiol. X-ray crystallographic analysis of sonneratioside A confirmed its structure and its absolute stereochemistry. Eudesmol ß-D-glucopyranoside (6) was also isolated from nature for the first time. The tyrosinase inhibitory activity was assayed for the new compounds together with seven known compounds. Among them, arbutin (12) showed the expected activity and luteolin 7-O-rutinoside (10) showed comparable activity to arbutin.

Dodelates A-E: Five dimeric eudesmane sesquiterpenoids from Dobinea delavayi.

Dodelates A-E (1-5), five angeloylated eudesmane sesquiterpenoid dimers were isolated from the roots of Dobinea delavayi. Their structures were elucidated by extensive spectroscopic data and single-crystal X-ray diffraction analyses. A possible biosynthetic pathway of these five compounds was proposed. Compounds 1 and 3 exhibited moderate antimalarial activities against Plasmodium yoelii BY265RFP.

Further sesquiterpenoids from the rhizomes of Homalomena occulta and their anti-inflammatory activity.

The rhizomes of Homalomena occulta are called Qian-nian-jian in Traditional Chinese Medicine (TCM), which is widely consumed in China owing to its health benefits for the treatment of rheumatoid arthritis and for strengthening tendons and bones. A phytochemical investigation on this famous TCM yielded 19 sesquiterpenoids (1-19) with various carbocyclic skeletons including isodaucane (2, 8, and 9), guaiane (3), eudesmane (4 and 10-15), oppositane (5, 16, and 17), and aromadendrane (18 and 19) types. The structures of new compounds, Homalomenins A-E (1-5), were determined by diverse spectroscopic data. Compound 1 possessed a rare sesquiterpenoid skeleton and compound 5 represented the first example of 1,4-oxa-oppositane sesquiterpenoid. These isolates were evaluated for their inhibitory effects on COX-2 mRNA, COX-2 protein expression, and prostaglandin E2 (PGE2) production in Raw264.7 cells, which demonstrated that compounds 5, 18, 19 showed potent anti-inflammatory activity by suppressing LPS-induced COX-2 expression and PGE2 production in a dose-dependent manner.

Potent inhibition of gastric cancer cells by a natural compound via inhibiting TrxR1 activity and activating ROS-mediated p38 MAPK pathway.

Thioredoxin reductase 1 (TrxR1) has emerged as a potential target for cancer therapy, because it is overexpressed in several types of cancers and associated with increased tumour growth and poor patient prognosis. Alantolactone (ALT), a natural sesquiterpene lactone originated from traditional folk medicine Inula helenium L., has been reported to exert antitumor activity in various tumours. However, the effect of ALT on human gastric cancer cells and its underlying mechanism remains unknown. In this study, we showed that ALT inhibited cell proliferation and induced cell apoptosis in gastric cancer cells. Mechanistically, our data found that ALT induced reactive oxygen species (ROS) production by inhibiting TrxR1 activity, resulting in the activation of p38 mitogen-activated protein kinase (MAPK) pathway and eventually cell apoptosis in gastric cancer cells. And the effects of ALT were reversed by pre-treatment with NAC (a scavenger of ROS). Further investigation revealed that ALT displayed synergistic lethality with erastin against gastric cancer cells, which demonstrating combined inhibition of TrxR1 and glutathione (GSH) leads to a synergistic effect in gastric cancer cells. More importantly, ALT treatment markedly reduced the activity of TrxR1 in vivo and inhibited the growth of gastric cancer xenografts without exhibiting significant toxicity. Taken together, these findings suggest that ALT may be used as a novel therapeutic agent against human gastric cancer.

Synthesis and discovery of a drug candidate for treatment of idiopathic pulmonary fibrosis through inhibition of TGF-ß1 pathway.

In this study, anti-IPF lead compounds 42 and 44, derived from natural sesquiterpene lactones Isoalantolactone and alantolactone, were discovered by screening from a high-throughput TGF-ß1 reporter luciferase assay. Notably, they could reduce the myofibroblast activation and extracellular matrix deposition both in vitro and in vivo. Additionally, compounds 42 and 44 could significantly attenuate bleomycin-induced pulmonary fibrosis in mice. Further validation of pharmacokinetics study and toxicity evaluation indicated that compound 44 might be a promising anti-IPF drug candidate.

Chemical composition and α-amylase inhibitory activity of the essential oil from Sabina chinensis cv. Kaizuca leaves.

Sabina chinensis cv. Kaizuca (SCK) is a variant of S. chinensis L. The essential oil from its leaves exhibited α-amylase inhibitory activity in vitro and the IC50 value was 187.08 ± 0.56 µg/mL. Nineteen compounds were identified from this essential oil by gas chromatography-mass spectrometry (GC-MS) analysis. The major compounds identified were bornyl acetate (42.6%), elemol (20.5%), ß-myrcene (13.7%) and ß-linalool (4.0%). In order to study the reason of the α-amylase inhibitory activity of this essential oil, the identified compounds were docked with α-amylase by molecular docking individually. Among these compounds, γ-eudesmol exhibited the lowest binding energy (-6.73 kcal/mol), followed by α-copaen-11-ol (-6.66 kcal/mol), cubedol (-6.39 kcal/mol) and α-acorenol (-6.12 kcal/mol). The results indicated that these compounds were the active ingredients responsible for the α-amylase inhibitory activity of essential oil from SCK.