Lactone ring-opening seco-guaianolide involved heterodimers linked via an ester bond from Artemisia argyi with NO inhibitory activity

Artemvulactone E isolated from Artemisia vulgaris L. ameliorates lipopolysaccharide-induced inflammation in both RAW264.7 and zebrafish model

Introduction

Natural plants are valuable resources for exploring new bioactive compounds. Artemisia vulgaris L. is a traditional Chinese medicinal herb that has been historically used for treating multiple diseases. Active compounds isolated and extracted from A. vulgaris L. typically possess immunomodulatory and anti-inflammatory properties. Artemvulactone E (AE) is a new sesquiterpene lactone isolated and extracted from A. vulgaris L. with unclear biological activities.

Methods

The immunoregulatory effects of AE on macrophages were assessed by ELISA, RT-qPCR, immunofluorescence, and western blot assay. The effect of AE on lipopolysaccharide (LPS) -relates signaling pathways was examined by western blot assay. In zebrafish models, the larvae were yolk-microinjected with LPS to establish inflammation model and the effect of AE was evaluated by determining the survival rate, heart rate, yolk sac edema size, neutrophils and macrophages infiltration of zebrafish. The interaction between AE and Toll-like receptor 4 (TLR4) was examined by molecular docking and dynamic stimulation.

Results

AE reduced the expression and secretion of pro-inflammatory cytokines (TNF-α and IL-6), inflammatory mediators iNOS and COX-2, as well as decreases the production of intracellular NO and ROS in LPS-stimulated macrophages. In addition, AE exerted its anti-inflammatory effect synergistically by inhibiting MAPK/JAK/STAT3-NF-κB signaling pathways. Furthermore, AE enhanced the survival rate and attenuated inflammatory response in zebrafish embryos treated with LPS. Finally, the molecular dynamics results indicate that AE forms stable complexes with LPS receptor TLR4 through the Ser127 residue, thus completely impairing the subsequent activation of MAPK-NF-κB signaling.

Conclusion

AE exhibits notable anti-inflammatory activity and represents as a potential agent for treating inflammation-associated diseases.

Sesquiterpene from Artemisia argyi seed extracts: A new anti-acute peritonitis agent that suppresses the MAPK pathway and promotes autophagy

To find novel anti-inflammatory drugs, we screened anti-inflammatory compounds from 18 different types of Artemisia argyi seed extracts. The in vitro and in vivo anti-inflammatory activities of the screened compounds and their mechanisms were characterized. We first detected the cytotoxic effect of the compounds on RAW264.7 cells and the inhibitory effect on LPS-induced NO release. It was found that sesquiterpenoids CA-2 and CA-4 had low cytotoxic and strong NO inhibitory activity with an IC50 of 4.22 ± 0.61 μM and 2.98 ± 0.23 μM for NO inhibition, respectively. Therefore, compound CA-4 was studied in depth. We found that compound CA-4 inhibited LPS-induced pro-inflammatory factor production and M1 macrophage differentiation in RAW264.7 cells. Additionally, CA-4 inhibited the expression of p-ERK1/2, p-JNK, iNOS, and COX-2 by blocking the MAPK signaling pathway. CA-4 also promoted the expression of autophagy-related proteins such as LC3 II and Beclin-1 by inhibiting activation of the PI3K/AKT/mTOR signaling pathway, and promoted the generation of autophagosomes. Finally, CA-4 significantly inhibited the degree of inflammation in mice with acute peritonitis, showing good anti-inflammatory activity in vivo. Consequently, compound CA-4 may be a promising drug for the treatment of acute inflammatory diseases and provide new ideas for the synthesis of novel anti-inflammatory compounds.

Artemongolins A-K, undescribed germacrane-guaiane sesquiterpenoid dimers from Artemisia mongolica and their antihepatoma activities

Artemongolins A-K (1-11), which are undescribed sesquiterpenoid dimers, were obtained from Artemisia mongolica and characterized through comprehensive spectral data, including HRESIMS, IR, 1D and 2D NMR, and ECD calculations. The absolute configurations of compounds 1, 4, and 7 were undoubtedly determined by a single-crystal X-ray crystallography. Artemongolins A-K (1-11) featured a rare 5/7/5/5/5/10 hexacyclic system composed of a germacrene and a guaianolide by a fused 2-oxaspiro[4,4]nonane-1-one ring system. Antihepatoma evaluation against three human hepatoma cell lines demonstrated that the most active compounds 5 and 6 displayed inhibitory activity with IC50 values of 88.6 and 57.0 (HepG2), 59.1 and 26.4 (Huh7), and 67.5 and 32.5 (SK-Hep-1) µM, respectively.

Iso-seco-tanapartholide from Artemisia argyi inhibits the PFKFB3-mediated glycolytic pathway to attenuate airway inflammation in lipopolysaccharide-induced acute lung injury mice

ETHNOPHARMACOLOGICAL RELEVANCE

In traditional Chinese folk medicine, Artemisia argyi H.Lév. & Vaniot (A. argyi) has been used for thousands of years, and it is clinically used to treat bronchitis and asthma. However, the mechanism of action of A. argyi on respiratory tract inflammation is not clear. Accumulating evidence that phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 (PFKFB3) is actively expressed in inflammation. Here, we found that iso-seco-tanapartholide (IST), a sesquiterpene isolated from A. argyi, exhibited potent anti-inflammatory activity and significant inhibition of PFKFB3 expression. Therefore, we evaluated the effect of IST on airway inflammation and revealed its possible mechanisms.

AIM OF THE STUDY

This study aimed to investigate the protective effect and possible mechanism of IST in lipopolysaccharide (LPS)-induced acute lung injury in mice.

MATERIALS AND METHODS

In vitro, RAW264.7 cells and BMDMs were stimulated with LPS, and the level of NO and inflammatory factors TNF-α, IL-1β, and IL-6 were detected by Griess reagent and ELISA, respectively. The effect of IST on the levels of PFKFB3 and its downstream proteins (p-STAT3, p-p65) in cells was assayed by western blotting. Lactate and glycolytic phenotypes were detected by lactate kit and Seahorse assay. In vivo, a mouse model of acute lung injury was induced by LPS, and the levels of inflammatory factors were measured by ELISA. Expression of PFKFB3 and its downstream proteins (p-STAT3, p-p65) in mouse alveolar macrophages by western blotting analysis. Lung permeability assessment by Evans Blue dye assay. H&E staining and Immunocytochemistry were used to observe the protection of IST against lung injury.

RESULTS

IST significantly reduced LPS-induced expression of PFKFB3 and its downstream proteins (p-STAT3, p-p65). The inhibition of PFKFB3 has an impact on the glycolytic phenotype, such as a reduction in the rate of extracellular acidification (ECAR) and elevated lactate levels, and an increase in the rate of cellular oxygen consumption (OCR). Furthermore, IST inhibited LPS-induced NO release and increased the expression of pro-inflammatory factors TNF-α, IL-1β, and IL-6. In vivo, IST reduced pulmonary edema in LPS-induced acute lung injury, improved lung function, and reduced levels of inflammatory factors and lactate secretion.

CONCLUSIONS

These results suggest that IST improves the characteristics of ALI by inhibiting the expression of the PFKFB3-mediated glycolytic pathway and may be a potential anti-inflammatory agent for inflammation-related lung diseases.

Artemongolides A-F, undescribed sesquiterpenoid dimers from Artemisia mongolica and their antihepatic fibrosis activities

Artemongolides A-E (1-5), an unusual class of diseco-guaianolides featuring a rare fused 7-methylbicyclo[2.2.1]-2-ene-7-heptanol ring system, and artemongolide F (6), the first example of [4 + 2] Diels-Alder type adducts presumably incorporating a chain farnesane sesquiterpene and a guaianolide diene, were isolated from the whole plant of Artemisia mongolica. Their structures were elucidated based on the spectroscopic analyses of UV, IR, MS, and 1D and 2D NMR spectra. The absolute configurations of artemongolides A (1) and F (6) were determined by single-crystal X-ray crystallography, and those of artemongolides B-E (2-5) were established by ECD calculations. Cytotoxicity evaluation suggested that compound 1 exhibited activity against HSC-LX2 cells with an IC₅₀ value of 165.0 μM, equivalent to that of the positive control silybin (IC₅₀, 146.4 μM). Preliminary mechanism studies revealed that compound 1 could inhibit the deposition of human collagen type I (Col I), human hyaluronic acid (HA), and human laminin (HL) with IC₅₀ values of 123.8, 160.4, and 139.20 μM.

Sesquiterpenoids and triterpenoids with anti-inflammatory effects from Artemisia vulgaris L

In this study, eight undescribed sesquiterpenoids (artemvulactone A-G and artemvulemdiol A), and two undescribed triterpenoids, (3S)-dammar-20,25-diene-3-hydroxy-24-one and (3S,23E)-dammar-20,23-diene-25- methoxy-3-ol were isolated from the leaves of Artemisia vulgaris L., together with ten known sesquiterpenoids and three known triterpenoids. The structures of these undescribed terpenoids were determined by extensive spectroscopy methods, including 1D and 2D-NMR, HRESIMS, IR, UV, X-ray diffraction, and ECD. The absolute configurations of artemvulactone A, artemvulactone D, and artemvulactone E were determined by X-ray diffraction (Cu Kα). All isolates were evaluated for their anti-inflammatory efficacy by detecting the expression of inflammatory mediator NO in LPS-induced RAW264.7 cells, and the results indicated that artemvulactone E exhibited significant anti-inflammatory effect with an IC50 value of 0.9 ± 0.2 μM. Furthermore, artemvulactone E could reduce LPS-induced COX-2 protein expression dose-dependently by western blotting experiments.

Jing Si Herbal Drink as a prospective adjunctive therapy for COVID-19 treatment: Molecular evidence and mechanisms

Background

SARS-CoV-2 has led to a sharp increase in the number of hospitalizations and deaths from pneumonia and multiorgan disease worldwide; therefore, SARS-CoV-2 has become a global health problem. Supportive therapies remain the mainstay treatments against COVID-19, such as oxygen inhalation, antiviral drugs, and antibiotics. Traditional Chinese medicine (TCM) has been shown clinically to relieve the symptoms of COVID-19 infection, and TCMs can affect the pathogenesis of SARS-CoV-2 infection in vitro. Jing Si Herbal Drink (JSHD), an eight herb formula jointly developed by Tzu Chi University and Tzu Chi Hospital, has shown potential as an adjuvant treatment for COVID-19 infection. A randomized controlled trial (RCT) of JSHD as an adjuvant treatment in patients with COVID-19 infection is underway

Objectives

This article aims to explore the efficacy of the herbs in JSHD against COVID-19 infection from a mechanistic standpoint and provide a reference for the rational utilization of JSHD in the treatment of COVID-19.

Method

We compiled evidence of the herbs in JSHD to treat COVID-19 in vivo and in vitro.

Results

We described the efficacy and mechanism of action of the active ingredients in JSHD to treat COVID-19 based on experimental evidence. JSHD includes 5 antiviral herbs, 7 antioxidant herbs, and 7 anti-inflammatory herbs. In addition, 2 herbs inhibit the overactive immune system, 1 herb reduces cell apoptosis, and 1 herb possesses antithrombotic ability.

Conclusion

Although experimental data have confirmed that the ingredients in JSHD are effective against COVID-19, more rigorously designed studies are required to confirm the efficacy and safety of JSHD as a COVID-19 treatment.

Iso-seco-tanapartholide activates Nrf2 signaling pathway through Keap1 modification and oligomerization to exert anti-inflammatory effects

Covalent modification of Keap1 results in reducing ubiquitination and the accumulation of Nrf2, which subsequently initiates the transcription of cellular anti-oxidant and anti-inflammatory genes. Iso-seco-tanapartholide (IST), a sesquiterpene isolated from the traditional Chinese medicine Artemisia argyi, had been reported to possess NF-κB inhibitory activity. However, its deep anti-inflammatory effects and direct target have never been reported. Here we show that IST activated Nrf2 and increased its target gene expression. In particular, LPS-caused inflammation in vitro and in vivo was mitigated by IST-induced Nrf2 activation but aggravated by Nrf2 inhibition. Mechanically, IST targeted Keap1 proteins via alkylating its cysteine residues 151, 273, 288, and so on. Subsequently, the modifying agent IST was displaced by intermolecular sulfhydryl disulfide interchange to lead to a disulfide dimer of Keap1. The resulting conformational change of Keap1 liberated Nrf2 from sequestration and allowed it translocation to the nucleus to activate the transcriptional program. Further studies demonstrated that Keap1 dimer formation contributed to the anti-inflammatory effects of IST. Taken together, our findings reveal a new mechanism for Nrf2 activation and provide a potential lead compound to treat inflammatory diseases through targeting Keap1.

Fissisternoids A and B, two 2′,5′-quinodihydrochalcone-based meroterpenoid enantiomers with unusual carbon skeletons from Fissistigma bracteolatum

Compound 1 represents an unprecedented meroterpenoid featuring a unique tricyclo [3,3,1,01′,5′] decane central framework and 2 possesses a rare 6/6/5/4 tetracyclic carbon skeleton were isolated from Fissistigma bracteolatum.

New guaiane-type sesquiterpenoid dimers from Artemisia atrovirens and their antihepatoma activity

Leading by cytotoxicity against HepG2 cells, bioactivity-guided fractionation of the EtOAc fraction from Artemisia atrovirens led to the isolation of 18 new guaianolide dimers, artematrolides A–R and lavandiolides A, B, C, H, and J. Eight compounds (1, 4, 10, 12, 13, and 19–21) were unambiguously confirmed by the single-crystal X-ray diffraction analyses, and the others were elucidated based on IR, UV, HRESIMS, 1D and 2D NMR experiments, and comparison of the experimental and calculated ECD data. Structurally, all of them were [4 + 2] Diels–Alder adducts of two monomeric guaianolides. The isolates were evaluated for their cytotoxicity against three human hepatoma cell lines, and 19 compounds demonstrated cytotoxicity against HepG2, SMMC-7721, and Huh7 cell lines. Especially, compounds 1, 12, 14, and 15 exhibited cytotoxicity with IC₅₀ values of 4.4, 3.8, 7.6, and 6.7 μmol/L (HepG2), 9.6, 4.6, 6.6, and 6.0 μmol/L (SMMC-7721), and 7.6, 4.5, 6.9, and 5.6 μmol/L (Huh7), respectively. Notably, compound 12 showed the most promising activity against three human hepatoma cell lines and dose-dependently inhibited cell migration and invasion, induced G2/M cell cycle arrest and cell apoptosis in HepG2 cells, down-regulated the expression of BCL-2 and PARP-1, and activated PARP-1 to up-regulate the expression of cleaved-PARP-1.

Cytotoxic guaianolides and seco-guaianolides from Artemisia atrovirens

A phytochemical investigation of a medicinal plant Artemisia atrovirens was carried out, resulting in the characterization of a novel bis-nor seco-guaianolide, seco-atrovirenolide A (1), a new 1,10-seco-guaianolide derivative, seco-atrovirenoic acid A (2), and a new artifact 10-methanoyloxy-seco-atrovirenoic acid A (3), together with eight known guaianolide and seco-guaianolide derivatives (4-11). The structures of new compounds were fully established by extensive analysis of MS, 1D and 2D NMR spectroscopic data. The absolute configurations of the isolated compounds were confirmed by TDDFT ECD calculation, Mosher's method, and X-ray crystal diffraction experiment. All the compounds were tested in vitro for their cytotoxicity against HL-60 and A549 cell lines. Some of them showed moderate inhibitory activity against HL-60 cell lines with IC₅₀ values ranging from 5.99 to 11.74 μM.

Monomeric and dimeric sesquiterpene lactones from Artemisia heptapotamica

One new dimeric (1) and two monomeric sesquiterpene lactones (5 and 13), together with 10 known compounds (2-4, 6-12), were isolated from Artemisia heptapotamica collected in Almaty region of Kazakhstan. All compounds were isolated from this plant for the first time. The structures of the new compounds were mainly achieved by extensive analysis of MS, 1D and 2D NMR spectroscopic data, and ECD spectrum as well. The inhibitory activities of all isolates against activation of NF-κB induced by LPS were assessed on a THP1-Dual cell model. Some of them showed strong inhibitory activity with IC₅₀ values ranging from 2 to 25 μmol·L^-1.

Natural disesquiterpenoids: an update

This review highlights the progress on the isolation, bioactivity, biogenesis and total synthesis of dimeric sesquiterpenoids since 2010.

Sesquiterpenoids from Artemisia argyi and their NO production inhibitory activity in RAW264.7 cells

Investigation into the chemical diversity of Artemisia argyi led to the discovery of two new (1, 4) and four known (2-3, 5-6) sesquiterpenoids. The new structures were determined via extensive spectroscopic data, including IR, UV, MS, and NMR, and the absolute configurations of these compounds were elucidated by calculated ECD method. All isolates were tested for their inhibitory activity against NO production in RAW 264.7 macrophages, and the isolated sesquiterpenoids exhibited NO production inhibitory activity with IC₅₀ values ranging from 1.91 to 36.52 μM.

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.