Arglabin: A mediator of inflammasome modulated and independent myocardial injury (PARA-AMI study)

BACKGROUND

Arglabin is a plant alkaloid (sesquiterpene lactone) that is used as an anticancer drug. It has potential anti-diabetic and anti-atherogenic effects.

PURPOSE

Arglabin has drawn particular attention because of its therapeutic effects as an anti-inflammatory agent in multiple diseases. Since arglabin inhibits Epidermal Growth Factor Receptor (EGFR) tyrosine kinase, concerns for cardiotoxic effects are valid. The present study was designed to investigate the protective effects of arglabin on the myocardium.

STUDY DESIGN

This study was designed to evaluate the effect of arglabin on the myocardium in an experimental model of myocardial necrosis in rats. Different doses of arglabin (2.5, 5, and 10 μg/kg) were investigated as pre-treatment for 21 days in the isoproterenol (ISO) model of myocardial necrosis groups and per se groups.

METHODS

On the 22nd day, hemodynamic, histopathological, electron microscopy, oxidative stress markers, inflammatory mediators, apoptotic markers, inflammasome mediators, and Western blot analysis were performed to evaluate the effects of arglabin.

RESULTS

Arglabin pre-treatment showed improvement in hemodynamic parameters and histopathological findings at low doses in isoproterenol-induced myocardial necrosis model of rats. Arglabin administration altered myocardial structure and modulated myocardial function via activation of NFκB/MAPK pathway that led to myocardial injury with an increase in dose.

CONCLUSION

Arglabin imparted partial cardio-protection via an inflammasome-dependent pathway and mediated injury through the inflammasome-independent pathway.

In silico toxicologic profile and in vivo trypanocidal activity of estafietin, a sesquiterpene lactone isolated from Stevia alpina Griseb

Chagas disease is an infection caused by the protozoan Trypanosoma cruzi, affecting 6-8 million people worldwide. Only two drugs are available for its treatment, having a limited efficacy and adverse side-effects. Estafietin is a sesquiterpene lactone isolated from Stevia alpina with in vitro activity against T. cruzi and low cytotoxicity against mammalian cells. The aim of this work was to predict the toxicologic profile of estafietin by in silico methods and assess its in vivo activity on a murine model of Chagas disease. Estafietin showed low toxicity according to pkCSM web tool and passed the PAINS filter from PAINS-remover web server. The treatment of infected mice with 1 mg/Kg/day of estafietin for five consecutive days administrated by intraperitoneal route significatively decreased parasitemia levels and reduced inflammatory infiltrates and myocyte damage on muscle tissue. These results suggest that estafietin had effect both on acute and chronic stages of the infection.

Synthesis of melampomagnolide B derivatives as potential anti-Triple Negative Breast Cancer agents

Triple-negative breast cancer (TNBC) is the most malignant and aggressive subtype of breast cancer. Currently, the treatment options to TNBC are limited and the discovery of new drugs and novel therapeutic strategies for treatment of TNBC is urgently needed. In this study, a series of melampomagnolide B (MMB) derivatives were designed, synthesized, and evaluated for their anti-TNBC activities. Compound 7 and 13a showed highly potent activity against different TNBC cells with IC50 values ranging from 0.37 μM to 1.52 μM, which demonstrated 3.6- to 54-fold improvement comparing to the parent compound MMB. The phenotypic effect revealed that compound 7 and 13a could inhibit metastasis, induce apoptosis and arrest cell cycle distribution of TNBC cells. Furthermore, the mechanism research indicated compounds 7 and 13a bound IKKβ and inhibited the IKKβ-mediated phosphorylation of IκB and p65, then inhibited the nuclear translocation of p65 and eventually regulated the genes related to metastasis, apoptosis and cell cycle under NF-κB control. Moreover, compound 7 inhibited the tumor growth in vivo, and the weights of spleens and livers were also reduced compared with control group which indicated that compound 7 could inhibit metastasis of TNBC in vivo. These findings indicate that compound 7 may be used as a promising lead compound for ultimate discovery of anti-TNBC drug.

A Divergent Clade KAI2 Protein in the Root Parasitic Plant Orobanche minor Is a Highly Sensitive Strigolactone Receptor and Is Involved in the Perception of Sesquiterpene Lactones

Strigolactones (SLs) were initially discovered as germination inducers for root parasitic plants. In 2015, three groups independently reported the characterization of the SL receptor in the root parasitic plant Striga hermonthica, which causes significant damage to crop production, particularly in sub-Saharan Africa. The characterized receptors belong to HYPOSENSITIVE TO LIGHT/KARRIKIN INSENSITIVE2 (HTL/KAI2), which is a member of the α/β-hydrolase protein superfamily. In non-parasitic plants, HTL/KAI2 perceives the smoke-derived germination inducer karrikin and a yet-unidentified endogenous ligand. However, root parasitic plants evolved a specific clade of HTL/KAI2 that has diverged from the KAI2 clade of non-parasitic plants. The S. hermonthica SL receptors are included in this specific clade, which is called KAI2 divergent (KAI2d). Orobanche minor is an obligate root holoparasitic plant that grows completely dependent on the host for water and nutrients because of a lack of photosynthetic ability. Previous phylogenetic analysis of KAI2 proteins in O. minor has demonstrated the presence of at least five KAI2d clade genes. Here, we report that KAI2d3 and KAI2d4 in O. minor have the ability to act as the SL receptors. They directly interact with SLs in vitro, and when expressed in Arabidopsis, they rescue thermo-inhibited germination in response to the synthetic SL analog GR24. In particular, KAI2d3 showed high sensitivity to GR24 when expressed in Arabidopsis, suggesting that this receptor enables highly sensitive SL recognition in O. minor. Furthermore, we provide evidence that these KAI2d receptors are involved in the perception of sesquiterpene lactones, non-strigolactone-type germination inducers.

Sesquiterpene lactones improve secretory diarrhea symptoms by inhibiting intestinal Ca2+-activated Cl- channel activities directly and indirectly

Secretory diarrhea caused by bacteria and viruses is usually accompanied by activation of the cystic fibrosis transmembrane conductance regulator (CFTR) and calcium-activated Cl- channels (CaCCs) in the intestinal epithelium. Inhibition of CFTR and CaCCs activities significantly reduces fluid losses and intestinal motility in diarrheal diseases. For this reason, CFTR and CaCCs are potential targets of therapeutic drug screening. Here, we reported that the sesquiterpene lactones, alantolactone (AL) and isoalantolactone (iAL), significantly inhibited ATP and Eact-induced short-circuit currents in T84, HT-29 and Fischer rat thyroid (FRT) cells expressing transmembrane protein 16A (TMEM16A) in a concentration-dependent manner. AL and iAL also inhibited the CaCC-mediated short-circuit currents induced by carbachol in the mouse colons. Both compounds inhibited forskolin-induced currents in T84 cells but did not significantly affect mouse colons. In vivo studies indicated that AL and iAL attenuated gastrointestinal motility and decreased watery diarrhea in rotavirus-infected neonatal mice. Preliminary mechanism studies showed that AL and iAL inhibited CaCCs at least partially by inhibiting Ca2+ release and basolateral membrane K+ channels activity. These findings suggest a new pharmacological activity of sesquiterpene lactone compounds that might lead to the development of treatments for rotaviral secretory diarrhea.

suppresses hepatocellular carcinoma growth by triggering ferritinophagy and mitochondrial damage

BACKGROUND

Hepatocellular carcinoma (HCC) is an aggressive tumor with limited treatment options, and it is the third leading cause of cancer-related deaths. Hence, novel therapeutic strategies are required to treat HCC. Eupatorium chinense L. is a traditional Chinese medicine (TCM) that can effectively neutralize heat and smoothen the flow of "Qi" through the liver. However, the anti-HCC effects of Eupatorium chinense L. remain unknown.

PURPOSE

The present study investigated the anti-HCC effects and the underlying mechanisms of the electrophilic sesquiterpenes isolated from E. chinense L. (EChLESs) in the regulation of ferroptosis and apoptosis in HCC cells.

STUDY DESIGN/METHODS

Cell viability was assessed by the MTT assay. Cell apoptosis was confirmed by flow cytometry and western blotting assay. Ferroptosis was assessed by flow cytometry, transmission electron microscopy, and western blotting assay. Ferritinophagy was detected by acridine orange staining and western blotting assay. Small interfering RNA of nuclear receptor coactivator 4 (NCOA4) was used to confirm the role of ferritinophagy in the therapeutic effect of EChLESs on HCC cells. A mouse xenograft model was constructed to determine the inhibitory effect of EChLESs on HCC in vivo.

RESULTS

EChLESs induced apoptosis by disrupting mitochondrial membrane potential depolarization and mitochondrial reactive oxygen species. EChLESs induced ferroptosis as noted by a significant increase in mitochondrial disruption, lipid peroxidation, and intracellular iron level and decreased glutathione level. The apoptosis inhibitor Z-VAD-FMK and lipid reactive oxygen species scavenger ferrostatin 1 attenuated EChLESs-induced cell death. NCOA4-mediated ferritinophagy through autophagic flux was the crucial pathway for ferroptosis induced by EChLESs. NCOA4 knockdown alleviated EChLESs-induced cell death. EChLESs controlled the expression of NCOA4 at the transcriptional and post-transcriptional levels. In the in vivo experiment, EChLESs suppressed HCC growth in the xenograft tumor mouse model.

CONCLUSION

EChLESs enhances cell apoptosis through mitochondrial dysfunction and ferroptosis through NCOA4-mediated ferritinophagy. Thus, Eupatorium chinense L. could be a potential TCM for treating HCC.

Two new halogenated sesquiterpene lactones from Palisada intermedia

Two new sesquiterpene lactones, laurenolide A (1) and laurenolide B (2), along with six known compounds, palmitic acid (3), (R,R)-hexahydrofarnesyl acetone (4), trans-phytol acetate (5), cholesterol (6), cholesteryl acetate (7), cholesteryl heptadecanoate (8) were isolated from Palisada intermedia. The chemical structures of all compounds were elucidated by 1D and 2D-NMR spectroscopy and HR-ESI-MS analysis as well as compared with data in the literature. The petroleum ether, chloroform, ethyl acetate, methanol extracts and compounds 1, 2 were tested for the inhibition of two cancer cell lines MCF-7, NCI-H460 and they showed weak or none activities.

Targeting PPARγ/ NF-κB Signaling Pathway by Britannin, a Sesquiterpene Lactone from Inula aucheriana DC., in Gastric Cancer

BACKGROUND

Gastric cancer is one of the most common and deadliest malignancies in the world. Therefore, there is an urgent need to develop new and effective agents to reduce mortality. The plants of genus Inula have gained the attention of researchers worldwide as a rich source of potent medicinal compounds.

OBJECTIVE

This study explores the anti-cancer activity of Britannin, a sesquiterpene lactone isolated from Inula aucheriana DC., and its molecular mechanism in gastric cancer cells, AGS and MKN45.

METHODS

Cytotoxicity was evaluated through the MTT assay following 24 h, 48 h, and 72 h treatment with different concentrations of Britannin. Apoptosis rate and caspase-3 activity were measured 24 h after treatment by Britannin. . Western blotting was performed to determine the expression of the NF-κB, IκBα, and PPARγ proteins. Moreover, quantitative RT-PCR was applied to measure the expression of NF-κB target genes.

RESULTS

We showed that Britannin induced cell growth inhibition and apoptosis in gastric cancer cells. Britannin caused an elevation in mRNA and protein levels of PPARγ. The involvement of PPARγ was more confirmed using GW9662, a PPARγ inhibitor. Suppression of NF-κB was demonstrated by western blot analysis. Down-regulation of MMP-9, TWIST-1, COX-2, and Bcl-2 and up-regulation of Bax were also observed in gastric cancer cells.

CONCLUSION

These results imply that activation of the PPARγ signaling pathway through suppression of NF-κB underlies the anti-cancer properties of Britannin in gastric cancer. Therefore, Britannin could be considered as a promising anti-cancer candidate for further evaluation.

Phytochemical analysis of Artemisia kopetdaghensis: Sesquiterpene lactones with proapoptotic activity against prostate cancer cells

Phytochemical investigation of the aerial parts of Artemisia kopetdaghensis resulted in the isolation and characterization of three undescribed eudesmane-type sesquiterpene lactones, persianolide A, 4-epi-persianolide A, and 3α,4-epoxypersianolide A, together with three previously described eudesmane-type sesquiterpene lactones, 11-epi-artapshin, 1β,8α-dihydroxy-11α,13-dihydrobalchanin, and 1β-hydroxy-11-epi-colartin. The abundantly obtained 11-epi-artapshin was oxidized to undescribed 11α,13-dihydroeudesma-12,6α-olide-1,8-dione and 8β-hydroxy-11α,13-dihydroeudesma-12,6α-olide-1-one and acetylated to the undescribed 1,8-O-diacetyl-11α,13-dihydroeudesma-12,6α-olide. Structures were elucidated based on extensive spectral data analyses, including 1D and 2D NMR and HRESIMS. The absolute configuration was determined using calculated and experimental ECD spectral data. Compounds were subsequently subjected to the MTT assay to evaluate their cytotoxicity against prostate cancer cells (DU-145 and LNCaP). Related factors associated with the sequence of apoptosis were tested by ELISA, western blotting, and biochemical assay. Results suggested that 11-epi-artapshin hinders the growth of DU-145 cells through mitochondria-mediated apoptosis initiated by stimulation of ROS build-up, ΔΨm depletion, regulation of the Bax/Bcl-2 ratio, and activation of caspase 3, respectively.

Phytochemical analysis and anti-microbial activities of Artemisia spp. and rapid isolation methods of artemisinin

Artemisia species are important traditional medicinal plants of Ethiopia which are used for the treatment of infection and non-infection health problems. The genus Artemisia (Astraceae) consists of about 500 species worldwide. In this study, the main aim was to investigate chemical components of Artemisia spp. (A. abyssinica, A. absinthium and A. annua) and evaluate their antimicrobial activities against bacterial strains. The results indicated that the crude extract of these plants was effective against selected bacterial strains. Here we isolated the well-known antimalarial drug artemisinin (7 mg, 0.004%) from Artemisia annua leaves using a rapid n-hexane fractionation method. The n-hexane extract of A. abyssinica, ethyl acetate extract of A. absinthium and n-hexane of A. annua showed varying degrees of inhibiting effect against bacterial strains such as Staphylococcus aureus ATCC 25923 ^T, Salmonella enteritidis ATCC13076^T, Klebsiella pneumoniae ATCC1053^T, boydii ATCC1233^T, Escherichia coli ATCC 25922 ^T, hospital acquired Acinetobacter baumannii. The ethyl acetate extract of Artemisia absinthium (A.ab_e) showed the maximum inhibiting effect (35 mm) against A. baumannii. The minimum zone of inhibition (< 3 mm) was recorded for test extract of A.ap against Klebsiella pneumoniae ATCC1053^T. Ethyl acetate extract of A, absinthium (A.abe) was more effective against these selected bacterial strains and the zone of inhibition ranged from 5 to 35 mm. The minimum inhibition zone (8 mm) was detected against S. typhimurium ATCC 13311 ^T for both A.ac and n-hexane- EtOAc fraction (8:2) of A, abyssinica. The maximum zone of inhibition (25 mm) for fraction (A.ach F4) of A, abyssinica obtained by column chromatography was recorded against S. pyogen ATCC 19,615. However, there was no zone of inhibition detected for boydii ATCC1233^T due to these test extracts. Significant variations (P ≥ 0.05) were observed between all test extracts of these medicinal plants at 95% of confidence intervals. In this study, clear zones of inhibition were detected for the positive control (standard impregnated disks). Based on our results we recommend that various species of Artemisia spp. seem to have the potential for in-depth investigation for various antimicrobial activities that assisting the effort in searching for antimicrobial lead compounds.

In vitro metabolism of helenalin and its inhibitory effect on human cytochrome P450 activity

Sesquiterpene lactone helenalin is used as an antiphlogistic in European and Chinese folk medicine. The pharmacological activities of helenalin have been extensively investigated, yet insufficient information exists about its metabolic properties. The objectives of the present study were (1) to investigate the in vitro NADPH-dependent metabolism of helenalin (5 and 100 µM) using human and rat liver microsomes and liver cytosol, (2) to elucidate the role of human cytochrome P450 (CYP) enzymes in its oxidative metabolism, and (3) to study the inhibition of human CYPs by helenalin. Five oxidative metabolites were detected in NADPH-dependent human and rat liver microsomal incubations, while two reduced metabolites were detected only in NADPH-dependent human microsomal and cytosolic incubations. In human liver microsomes, the main oxidative metabolite was 14-hydroxyhelenalin, and in rat liver microsomes 9-hydroxyhelenalin. The overall oxidation of helenalin was several times more efficient in rat than in human liver microsomes. In humans, CYP3A4 and CYP3A5 followed by CYP2B6 were the main enzymes responsible for the hepatic metabolism of helenalin. The extrahepatic CYP2A13 oxidized helenalin most efficiently among CYP enzymes, possessing the K_m value of 0.6 µM. Helenalin inhibited CYP3A4 (IC₅₀ = 18.7 µM) and CYP3A5 (IC₅₀ = 62.6 µM), and acted as a mechanism-based inhibitor of CYP2A13 (IC₅₀ = 1.1 µM, K_I = 6.7 µM, and k_inact = 0.58 ln(%)/min). It may be concluded that the metabolism of helenalin differs between rats and humans, in the latter its oxidation is catalyzed by hepatic CYP2B6, CYP3A4, CYP3A5, and CYP3A7, and extrahepatic CYP2A13.

Synthesis and in vitro antifungal activity of new Michael-type amino derivatives of xanthatin, a natural sesquiterpene lactone from Xanthium strumarium L

Structural optimization using plant secondary metabolites as templates is one of the important approach to discover pesticide molecules with novel skeletons. Xanthatin, a natural sesquiterpene lactone isolated from the Xanthium plants (Family: Compositae), exhibits important biological properties. In this work, a series of Michael-type amino derivatives were prepared from xanthatin and their structures were characterized by ¹H NMR, ¹³C NMR and HR-MS, and their antifungal activities against several phytopathogenic fungi were evaluated according to the spore germination method and mycelium growth rate method in vitro. The results illustrated that compounds 2g (IC₅₀ = 78.91 µg/mL) and 2o (IC₅₀ = 64.51 µg/mL) exhibited more promising inhibition activity against spores of F. solani than precursor xanthatin, compounds 2g, 2l, and 2r exhibited remarkable antifungal effect on C. mandshurica with the average inhibition rates (AIRs) >90%, whereas the AIR of xanthatin was only 59.34%. Meanwhile, the preliminary structure-activity relationships suggested that the amino containing 2-methoxyethyl or 4-chlorophenylmethyl group appended in the C-13 position of xanthatin could yield potential compounds against fungal spores, and the exocyclic double bond of xanthatin is essential to maintain its mycelial growth inhibitory activity. Therefore, the aforementioned findings indicate that partial xanthatin amino-derivatives could be considered for further exploration as the potential lead structures toward development of the new environmentally friendly fungicidal candidates for sustainable crop protection.

Ethnopharmacology, phytochemistry, and bioactivities of Hieracium L. and Pilosella Hill (Cichorieae, Asteraceae) species

ETHNOPHARMACOLOGICAL RELEVANCE

Species of the genera Hieracium and Pilosella have been used in folk medicine for centuries in many parts of the world. The most wiedly used species is P. officinarum Vaill., included in the British and French Pharmacopoeias and sold as part of different commercial products.

AIM OF THE STUDY

This review critically appraises the state-of-art of ethnopharmacology, specialised metabolites, bioactivities, and toxicity of members of Hieracium and Pilosella. Thus, gaps in scientific knowledge can be identified, also focusing on the development of products with pharmacological applications.

MATERIALS AND METHODS

Literature data of Hieracium and Pilosella species were mainly retrieved using different electronic databases such as Web of Science, Google Scholar, SciFinder, and PubMed. Other electronic resources included worldwide databases on ethnobotany, ethnopharmacology, and phytochemistry as well as government reports. Additionally, ancient texts and local information such as PhD and MSc theses, and books were consulted.

RESULTS

A comprehensive analysis of the above mentioned sources revealed that only 34 out of the about 850 described species within the genera Hieracium and Pilosella have been reported in the context of traditional medicinal and ethnobotanical knowledge. The most often mentioned species is P. officinarum which has been widely used due to its diuretic effects. Other popular uses of Hieracium and Pilosella species include the treatment of skin, gastric, and intestinal diseases as well as respiratory and vascular ailments. Moreover, taxa of the two genera have been used as antiobiotics, antiseptics, antidiabetics, tonics, antiepileptics, antiphlogistics, emetics, wound healing drugs, astringents, haemostatics, and detoxificants. Finally, uses as a wild vegetable, fodder, plant for hunting and for charming rituals have also been mentioned. Phytochemical research revealed a richness in phenolic compounds and flavonoids. Moreover, coumarins, sesquiterpene lactones, terpenoids, and phytosterols were found in Hieracium and Pilosella. Experimental research conducted to support traditional uses mainly include in vitro tests, while assays based on in vivo models (including humans) are rather limited. Also, the vast majority of the studies did not identify the compounds responsible for the detected bioactivities. These established bioactivities include antidiabetic, anti-inflammatory, antibacterial, antimycotic, antiviral, cytotoxic and antiproliferative, diuretic, gastroprotective, antiepileptic, hypotensive, anti-obesity, arthropodicidal, and skin rejuvenating activities. Finally, limited toxicity studies have been conducted on members of Hieracium and Pilosella.

CONCLUSION

Taxa belonging to Hieracium and Pilosella have been confirmed to exert diuretic, anti-inflammatory, and antimicrobial effects, which is in line with their long traditional use. Moreover, the above mentioned fields of application hint to the most promising routes for the development of new marketable products. Nonetheless, additional data from an in-depth research on bio-active specialised metabolites such as sesquiterpenoids, sesquiterpene lactones, and coumarines, their bioactivities and toxicity, and their biosynthesis are still warranted.

Gaillardin, a potent sesquiterpene lactone induces apoptosis via down-regulation of NF-κβ in gastric cancer cells, AGS and MKN45

ETHNOPHARMACOLOGICAL RELEVANCE

The genus Inula has been traditionally used as folk medicine in treating different illnesses such as kidney stones, urethra infection, jaundice, bronchitis, respiratory diseases and cancer.

AIM OF THE STUDY

Gaillardin, a sesquiterpene lactone isolated from Inula oculus-christi, seems to have great potential as an anti-cancer agent. This study was carried out to evaluate the anti-cancer properties of Gaillardin in gastric cancer cells and also its possible underlying mechanism.

METHODS

The colorimetric MTT assay was used to assess metabolic activity of cells as an indicator of viability and cytotoxicity. Flow cytometry using Annexin V-FITC/PI was applied to detect and quantify the level of apoptosis. Detection of activated caspase-3, as a biochemical marker of apoptosis, was done using caspase-3 assay kit. Activation of NF-κB pathway was determined by western blotting. The mRNA expression levels of NF-κB target genes were measured using quantitative RT-PCR. Moreover, intracellular reactive oxygen species (ROS) production was evaluated.

RESULTS

Gaillardin significantly reduced cell viability in a time and dose-dependent manner. The inhibitory effect of Gaillardin was attributed to induction of apoptosis. Investigation about the underlying mechanism revealed that Gaillardin exerts its action through inhibition of NF-κB activation and subsequently down-regulation of genes (COX-2, MMP-9, TWIST-1, and BCl-2) regulated by NF-κB. Moreover, Gaillardin caused remarkable elevation in ROS production in AGS and MKN45 cells.

CONCLUSION

We provided evidences about the role of NF-κB pathway in the induction of apoptosis by the sesquiterpene lactone Gaillardin in AGS and MKN45 cells for the first time, which suggest Gaillardin could be considered as a promising natural agent for further investigations to identify new potent anticancer drugs in the future.

Germacrane sesquiterpenes from leaves of Eupatorium chinense inhibit protein tyrosine phosphatase

Three new germacrane-type sesquiterpene lactones (1-3) were isolated alongside seven known related congeners (4-10) from the leaves of Eupatorium chinense L. (Compositae). The planar structures of 1-3 were elucidated by their spectroscopic data, including 1D and 2D NMR spectra. The relative and absolute configurations of 1-3 were determined using NOESY experiments and electronic circular dichroism analyses. Compounds 1, 4, 5, and 7 inhibited protein tyrosine phosphatase (PTP) 1B activity with IC₅₀ values of 25, 11, 28, and 24 μM, respectively. Among these, compound 4 exhibited an inhibitory effect on T-cell PTP (TCPTP) with an IC₅₀ value of 25 μM. To our knowledge, this is the first study demonstrating the PTP inhibitory activity of the germacrane sesquiterpenes. The results show that compound 4 acts as an inhibitor of both PTP1B and TCPTP.

1β-Hydroxyalantolactone from Inulae Flos alleviated the progression of pulmonary fibrosis via inhibiting JNK/FOXO1/NF-κB pathway

Inulae Flos was widely distributed throughout Europe, Africa, and Asia, and was commonly used as a folk medicine in clinic for treating various respiratory diseases, including cough, asthma, bronchitis, pulmonary fibrosis, and pneumonia. However, the ingredients responsible for the pharmacology effects of I. Flos and the underlying mechanisms remain unclear. In this study, the effects of 16 known sesquiterpene lactones and flavonoids from I. Flos on TGF-β1-induced fibroblast activation were assessed by phenotypic high-content screening. Among those sixteen compounds, 1β-hydroxy alantolactone (HAL), the main characteristic sesquiterpene lactone from I. Flos, exhibited remarkable inhibitory activity. The further studies showed that HAL significantly inhibited the proliferation and induced the apoptosis of human fibroblast cell lines HELF and MRC-5 in a concentration-dependent manner. It also reduced intracellular ROS production, suppressed the mRNA expressions of E-cad, TGF-β1, Smad3, Col I, α-SMA and TNF-α, and downregulated protein expressions of α-SMA and F-actin. Furthermore, HAL significantly reduced the levels of HA, LN, PC-III and IV-C in serum, TNF-α and IL-6 in BALF, and TGF-β1, HYP and Col I in lung tissues of bleomycin (BLM)-treated rats. HAL significantly downregulated the expressions of p-JNK, FOXO1, p-p65, α-SMA, p-smad3 and Col I but upregulated p-FOXO1, which could be reversed by JNK agonist anisomycin. These results demonstrated that HAL induced the apoptosis of lung fibroblast cells activated by TGF-β1 and improved BLM-induced lung fibrosis in rats via inhibiting JNK/FOXO1/NF-κB pathway.

A new cytotoxic sesquiterpene lactone from Euphorbia microsphaera Boiss against human breast cancer (MCF-7) and human fibrosarcoma (HT1080) cells

A new guaianolide sesquiterpene lactone with cytotoxic properties was isolated from Euphorbia microsphaera Boiss. To determine the highest active fraction and isolate bioactive compounds, a bioassay guided fractionation approach was used. The general toxicity properties of the plant's extracts and fractions (fr_1-10) were assessed against Artemia salina, Oryzeaphilus mercator, and Tribolium castaneum. Cytotoxic activities were investigated against normal human foreskin fibroblasts and two malignant cell lines, including human breast cancer (MCF-7) and human fibrosarcoma cells (HT1080) using the MTT assay at different time points of 24, 48, and 72 h. Single crystal X-ray diffraction (SC-XRD) and mass spectrometry data were used to determine the structure of the active guaianolide sesquiterpene lactone (3aR,4S,4aS,5R,7aS,9aS)-5-hydroxy-5,8-dimethyl-3-methylene-2-oxo-2,3,3a,4,4a,5,6,7,7a, 9a decahydroazuleno [6,5-b] furan-4-yl acetate (named aryanin). Chloroformic fraction 7 (fr₇, LC₅₀ = 93.50 μg/mL for general toxicity) had the highest toxicity result, with a mortality rate of more than 50% for both insect species after 12 h at 15 mg/mL. The highest cytotoxicity of aryanin was observed on 24 h treated MCF-7 with an IC₅₀ of 13.81 μg/mL. After 24 h, the inhibition of MCF-7 cell proliferation was 92%-94% at concentrations of 25-50 μg/mL, respectively. On MCF-7, the IC₅₀ was found to be 49.35 μg/mL after 72 h. This compound had a considerable cytotoxicity (IC₅₀ ≤ 12.5 μg/mL, 24 h) on human foreskin fibroblasts. In contrast to the MCF-7 cell line, the proliferation of human foreskin fibroblasts was increased after 72 h.

Pulchelloid A, a sesquiterpene lactone from the Canadian prairie plant Gaillardia aristata inhibits mitosis in human cells

BACKGROUND

The Canadian prairie ecosystem presents a rich source of natural products from plants that are subjected to herbivory by grazing mammals. This type of ecological competition may contribute to the production of natural products of interest in cell biology and medical research. We provide the first biological description of the sesquiterpene lactone, pulchelloid A, which we isolated from the prairie plant, Gaillardia aristata (Asteraceae) and report that it inhibits mitosis in human cells.

METHODS AND RESULTS

We found that G. aristata (Blanket flower) extracts were cytotoxic to human cell lines and used phenotypic assays to characterize the bioactivity of extracts. Before dying, cells were characterized by a rounded morphology, phospho-histone H3 signals, mitotic spindles, and active Cdk1. By biology-guided fractionation of Gaillardia extracts, we isolated a sesquiterpene lactone named pulchelloid A. We used immunofluorescence microscopy and observed that cells treated with pulchelloid A have phospho-histone H3 positive chromosomes and a mitotic spindle, confirming that they were in mitosis. Treated cells arrest with an unusual phenotype; they enter a prolonged mitotic arrest in which the spindles become multipolar and the chromosomes acquire histone γH2AX foci, a hallmark of damaged DNA.

CONCLUSIONS

We propose that pulchelloid A, a natural product present in the prairie plant Gaillardia aristata, delays cells in mitosis. There is a growing body of evidence that a small number of members of the sesquiterpene lactone chemical family may target proteins that regulate mitosis.

Isolation of a natural product with anti-mitotic activity from a toxic Canadian prairie plant

We are investigating plants from the prairie ecological zone of Canada to identify natural products that inhibit mitosis in cancer cells. Investigation of plant parts from the Canadian plant species Hymenoxys richardsonii (Asteraceae) revealed that leaf extracts (PP-360A) had anti-mitotic activity on human cancer cell lines. Cells treated with leaf extracts acquired a rounded morphology, similar to that of cells in mitosis. We demonstrated that the rounded cells contained mitotic spindles and phospho-histone H3 using the techniques of immunofluorescence microscopy. By biology-guided fractionation of H. richardsonii leaves, we isolated a sesquiterpene lactone named hymenoratin, which had not been previously assigned a biological activity. Cells treated with hymenoratin have phospho-histone H3 positive chromosomes, a mitotic spindle, and enter a prolonged mitotic arrest in which the spindles become distorted. By Western blot analysis, hymenoratin treated cells acquire high levels of cyclin B and dephosphorylated Cdk1. There is a growing body of evidence that select members of the sesquiterpene lactone chemical family have anti-mitotic activity.

herbacea on bone morphogenetic protein-induced osteoblastic differentiation

A new unique sesquiterpene lactone, bicyclolamellolactone A (1), was isolated together with two known monocyclofarnesol-type sesquiterpenes, lamellolactones A (2) and B (3), from the Indonesian marine sponge Lamellodysidea sp. (cf. L. herbacea). The planar structure of 1 was assigned based on its spectroscopic data (1D and 2D NMR, HRESIMS, UV, and IR spectra). The relative and absolute configuration of 1 was determined by comparison of its calculated and experimental electronic circular dichroism spectra in combination with NOESY correlations. Compounds 1-3 inhibited bone morphogenic protein (BMP)-induced alkaline phosphatase activity in mutant BMP receptor-carrying C2C12 cells with IC₅₀ values of 51, 4.6, and 20 μM, respectively.

The yeast platform engineered for synthetic gRNA-landing pads enables multiple gene integrations by a single gRNA/Cas9 system

Saccharomyces cerevisiae is a versatile microbial platform to build synthetic metabolic pathways for production of diverse chemicals. To expedite the construction of complex metabolic pathways by multiplex CRISPR-Cas9 genome-edit, eight desirable intergenic loci, located adjacent to highly expressed genes selected from top 100 expressers, were identified and fully characterized for three criteria after integrating green fluorescent protein (GFP) gene - CRISPR-mediated GFP integration efficiency, expression competency assessed by levels of GFP fluorescence, and assessing growth rates of GFP integrated strains. Five best performing intergenic loci were selected to build a multiplex CRISPR platform, and a synthetic 23-bp DNA comprised of 20-bp synthetic DNA with a protospacer adjacent motif (PAM) was integrated into the five loci using CRISPR-Cas9 in a sequential manner. This process resulted in five different yeast strains harbouring 1-5 synthetic gRNA-binding sites in their genomes. Using these pre-engineered yeast strains, simultaneous integrations of 2-, 3-, 4-, or 5-genes to the targeted loci were demonstrated with efficiencies from 85% to 98% using beet pigment betalain (3-gene pathway), hygromycin and geneticin resistance markers. Integrations of the multiple, foreign genes in the targeted loci with 100% precision were validated by genotyping. Finally, we further developed the strain to have 6th synthetic gRNA-binding site, and the resulting yeast strain was used to generate a yeast strain producing a sesquiterpene lactone, kauniolide by simultaneous 6-gene integrations. This study demonstrates the effectiveness of a single gRNA-mediated CRISPR platform to build complex metabolic pathways in yeast.

Identification and characterization of SlbHLH, SlDof and SlWRKY transcription factors interacting with SlDPD gene involved in costunolide biosynthesis in Saussurea lappa

The genes involved in costunolide biosynthesis in Saussurea lappa have been identified recently by our lab. However, the study of transcriptional regulators of these genes was lacking for better opportunities for engineering the pharmacologically important biosynthetic pathway. Therefore, we cloned the promoter region of diphosphomevalonate decarboxylase gene (DPD) and analyzed its cis-acting regulatory elements to reveal the potential transcription factor (TF) binding sites for Dof, bHLH and WRKY family proteins in the gene promoter. The transcriptome study approach followed by the hidden Markov model based search, digital gene expression, co-expression network analysis, conserved domain properties and evolutionary analyses were carried out to screen out seven putative TFs for the DPD-TF interaction studies. Yeast one-hybrid assays were performed and three TFs were reported, namely, SlDOF2, SlbHLH3 and SlWRKY2 from Dof, bHLH and WRKY families, respectively that interacted positively with the DPD gene of the costunolide biosynthetic pathway. The tissue specific relative gene expression studies also supported the linked co-expression of the gene and its interacting TFs The present report will improve the understanding of transcriptional regulation pattern of costunolide biosynthetic pathway.

A comprehensive review of anticancer mechanisms of action of Alantolactone

Cancer is considered as the main challenge of human communities, and it annually imposes a significant economic burden on society. Natural products have been used for treatment of many diseases including inflammation, infections, neurological disorders, atherosclerosis, asthma and cancer for many years. Sesquiterpene lactones (STLs) refers to a group of natural products with different biological activities. A type of STL that has recently attracted much attention is Alantolactone (ALT). In recent years, many studies have investigated the molecular mechanism of this compound affecting cancer cells and results suggest that this compound exerts its anticancer effects by providing free radicals and inhibiting some of the signaling pathways that are effective in progression of cancer cells. The present study is aimed to introduce the latest molecular mechanisms of ALT proposed by researchers in recent years.

The sesquiterpene lactone eupatolide induces apoptosis in non-small cell lung cancer cells by suppressing STAT3 signaling

We aimed to evaluate the role of a natural sesquiterpene lactone, eupatolide, in non-small-cell lung cancer (NSCLC) and further explore its underlying mechanism on regulating the activation of signal transducer and activator of transcription 3 (STAT3), which is thought to have carcinogenic function in a variety of malignancies including lung cancer. Cell survival was measured by Cell Counting Kit-8 assay. in vivo experiments were performed by inoculating NSCLC cells into nude mice. Western blot and qRT-PCR were applied to detect the activation level of STAT3 and the mRNA levels of anti-apoptotic markers. The cell apoptosis was measured by Annexin V-FITC/PI Apoptosis Detection Kit. Our results showed that eupatolide suppressed the survival of NSCLC cells in a dose and time dependent manner. Furthermore, eupatolide increased the anti-tumor activity of the chemotherapeutic drugs cisplatin and 5-Fluoracil (5-FU). The xenograft study revealed that eupatolide suppressed tumor growth of NSCLC cells in vivo. Furthermore, eupatolide induced apoptosis by suppressing the activation of STAT3 in NSCLC cells. Sustained activation or knockdown of STAT3 suppressed and enhanced the activity of eupatolide, respectively. This paper is the first to report that eupatolide could effectively inhibit NSCLC progression, suggesting that eupatolide might be utilized as a novel STAT3 inhibitor for treating NSCLC.

What dominates the changeable pharmacokinetics of natural sesquiterpene lactones and diterpene lactones: a review focusing on absorption and metabolism

Sesquiterpene lactones (STLs) and diterpene lactones (DTLs) are two groups of common phytochemicals with similar structures. It's frequently reported that both exhibit changeable pharmacokinetics (PK) in vivo, especially the unstable absorption and extensive metabolism. However, the recognition of their PK characteristics is still scattered. In this review, representative STLs (atractylenolides, alantolactone, costunolide, artemisinin, etc.) and DTLs (ginkgolides, andrographolide, diosbulbins, triptolide, etc.) as typical cases are discussed in detail. We show how the differences of treatment regimens and subjects alter the PK of STLs and DTLs, with emphasis on the effects from absorption and metabolism. These compounds tend to be quite permeable in intestinal epithelium, but gastrointestinal pH and efflux transporters (represented by P-glycoprotein) have great impact and result in the unstable absorption. As the only characteristic functional moiety, the metabolic behavior of lactone ring is not dominant. The α, β-unsaturated lactone moiety has the strongest metabolic activity. While with the increase of low-activity saturated lactone moieties, the metabolism is led by other groups more easily. The phase I (oxidation, reduction and hydrolysis reaction) and II metabolism (conjugation reaction) are both extensive. CYP450s, mainly CYP3A4, are largely involved in biotransformation. However, only UGTs (UGT1A3, UGT1A4, UGT2B4 and UGT2B7) has been mentioned in studies about phase II metabolic enzymes. Our work offers a beneficial reference for promoting the safety evaluation and maximizing the utilization of STLs and DTLs.

Alantolactone inhibits stem-like cell phenotype, chemoresistance and metastasis in PC3 cells through STAT3 signaling pathway

Background and purpose:

Cancer stem cells (CSCs), as the subpopulation of cancer cells, are associated with carcinogenesis, chemoresistance, and metastasis in malignancies. Also, CSCs are considered as the major reason for treatment failure in prostate cancer (PCa). Alantolactone (ALT), exerts anticancer activity in different types of cancers. In the present study, the relationship between ALT and CSCs in PCa metastasis and the molecular mechanisms involved in the progression of PCa were investigated.

Experimental approach:

In this study, to evaluate cell viability, MTT assay was performed. Then, PC3 cells were treated with nontoxic concentrations of ALT and after this step wound-healing assay, colony-formation assay and chemosensitization assay were applied to determine cell migration, the ability of colony formation, and chemoresistance, respectively. Also, real-time polymerase chain reaction and western blotting were used for the determination of genes and protein expression, respectively.

Findings/Results:

Our finding showed that ALT at nontoxic concentrations (0.01 and 0.1 μM) for 72 h suppressed the STAT3 phosphorylation and signaling pathway. Also, ALT was able to modulate the stemness of PCa cells through downregulation of expression of SOX2, Oct-4, Nanog, CD133, CD44, and upregulation of p53 expression. On the other hand, we further found that ALT in nontoxic concentrations sensitized PCa cells to cisplatin

Conclusion and implications:

ALT combated the stemness of cancer cells and metastasis by antagonizing of STAT3 signaling pathway. In addition, ALT exhibited anti-metastatic properties and may have potential as a new chemotherapy agent for the reduction of PCa metastasis.

CYP71BL9, the missing link in costunolide synthesis of sunflower

Despite intensive research in recent years, the biosynthetic route to costunolide in sunflower so far remained obscured. Additional P450 sequences from public sunflower transcriptomic database were screened to search for candidate enzymes which are able to introduce the 6α-hydroxy-group required for the esterification with the carboxy group of germacarane A acid, the final step in costunolide formation. CYP71BL9, a new P450 enzyme from sunflower was shown to catalyze this hydroxylation, hence being identified as HaCOS. Phylogentically, HaCOS is closer related to HaG8H than to any other known costunolide synthase in Asteraceae.The enzyme was successfully employed to reconstruct the sunflower biosynthesis of costunolide in transformed tobacco. Contrary, in yeast, only minor amounts of sesquiterpene lactone was produced, while 5-hydroxyfarnesylic acid was formed instead. HaCOS in combination with HaG8H produced 8β-hydroxycostunolide (eupatolide) in transformed plants, thus indicating that sunflower possesses two independent modes of eupatolide synthesis via HaCOS and via HaES. The lack of HaCOS expression and of costunolide in trichomes suggests that the enzyme triggers the costunolied synthesis of the inner tissues of sunflower and might be linked to growth regulation processes.

The investigation of the potential antidepressant-like activity of Xanthium orientale subsp. italicum (Moretti) Greuter in rodents

ETHNOPHARMACOLOGICAL RELEVANCE

Ethnobotanical surveys revealed that Xanthiumorientale subsp. italicum (Moretti) Greuter has been used against central nervous system disorders in Turkish folk medicine. The aim of the present study is to verify the folkloric assertion on this plant. The compounds responsible for the activity were investigated using bioassay-guided fractionation procedures.

MATERIALS AND METHODS

The antidepressant activity of the aqueous, n-hexane, ethyl acetate (EtOAc), methanol (MeOH) extracts; fractions and isolated compounds from active MeOH extract were evaluated by using the in vitro MAO inhibition assay and three different in vivo models namely forced swimming test, tail suspension test, and antagonism of tetrabenazine-induced ptosis, hypothermia, and suppression of locomotor activity. The results were compared with control and reference groups, and active compounds of the plant have been determined. Through the bioassay-guided fractionation procedures, two compounds were isolated from the active fraction and their structures were elucidated by spectroscopic methods.

RESULTS

The MeOH extract of the plant was found to possess antidepressant-like activity. This extract was then subjected to chromatographic techniques. Isolated sesquiterpene lactones were elucidated as xanthatin (1) and xanthinosin (2), which were responsible for the antidepressant-like activity.

CONCLUSIONS

This study discovered the antidepressant potential of X. orientale subsp. italicum. Using bioassay-guided fractionation and isolation techniques, xanthatin (1) and xanthinosin (2) were determined as the main active components of the leaves.

Ergolide, a potent sesquiterpene lactone induces cell cycle arrest along with ROS-dependent apoptosis and potentiates vincristine cytotoxicity in ALL cell lines

ETHNOPHARMACOLOGICAL RELEVANCE

Inula oculus christi belongs to the family of Asteraceae and it was traditionally wide used in treatment of kidney stones and urethra infection; besides, recently the potent sesquiterpene lactones isolated from inula species has gained increasing attention in cancer treatments. This study investigates the anti-cancer properties and underlying mechanism of ergolide isolated from Inula oculus christi against leukemic cell lines.

METHODS

Viability, metabolic activity and proliferation evaluated using different index of MTT assay such as IC₅₀ and GI₅₀. Human erythrocytes were used to evaluate hemolytic activity. Flow-cytometry was used to detect and measure ROS level, and the induction of apoptosis and autophagy were evaluated using Annexin V/PI, Acridine Orange staining, respectively. Moreover, qRT-PCR was performed to examine the expression of a large cohort of crucial regulatory genes. Tunel assay was also carried out to assess morphologically ergolide effects.

RESULTS

Ergolide did not exert ant cytotoxicity against non-tumorous cells and did not cause noticeable hemolysis. It also caused ROS production during early hours after treatment of cells which was then followed by cell cycle arrest in G0/G1 phase and autophagy induction. Using N-acetyl-L-cysteine (NAC), we found that ergolide could not increase ROS and induce autophagy and moreover repressed cell death, indicating that ergolide induce cell death through ROS-dependent manner by altering the expression of pro apoptotic related genes. Autophagy inhibition also potentiated ergolide-induced cell death. Furthermore, ergolide intensified vincristine cytotoxicity against acute lymphoblastic leukemia (ALL) cell lines revealed robust synergistic properties of ergolide with VCR.

CONCLUSION

Here we showed that ergolide could be considered as a potent natural compound against leukemic cells by inducing cell cycle arrest followed by dose-dependent cell death. Based on results, Autophagy response in a result of ROS accumulation acted as a survival pathway and blocking this pathway could noticeably increase ergolide cytotoxicity on ALL cell lines.

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.

A new bilobalide isomer and two cis-coumaroylated flavonol glycosides from Ginkgo biloba leaves

A new bilobalide isomer (1), together with two flavonol glycosides (2, 3), have been isolated and elucidated from the extract of Ginkgo biloba leaves. Significantly, 1 was a new sesquiterpene lactone with two lactone ring groups, both 2 and 3 were two flavonol glycosides with a same cis-coumaroylated fragment. Their chemical structures were elucidated by NMR and MS spectroscopic date and the absolute configuration of 1 was specific established by Cu-Kα X-ray crystallographic analyses. However, 1-3 showed no obvious anti-platelet aggregation activity.

Anti-inflammatory activity of the sesquiterpene lactone diacethylpiptocarphol in dextransulfate sodium-induced colitis in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Sesquiterpene lactones are organic compounds derived mainly from plants that exhibit anti-inflammatory and antitumor activities being one of the key mechanism of action of NF-kB pathway and synthesis of cytokines such as IL-1 and TNF- α.

AIM OF THE STUDY

The overall objective of the present study was to evaluate the anti-inflammatory action of a sesquiterpene lactone diacethylpiptocarphol (DPC) from Vernonia scorpioides (Lam.) Pers. and parthenolide (PTH) in Balb-c mice with DSS-induced colitis.

MATERIALS AND METHODS

The anti-inflammatory effects of Intraperitonial administration of DPC (5 mg/kg/day) were evaluated in Balb/c mice with DSS-induced colitis, and further the body weight measurement, TNF-α and TGF-β level was determined.

RESULTS

After intraperitoneal treatment for one week, DSS-induced colitis was significantly reduced in mice treated with either of both sesquiterpenes lactones, as witnessed by reduced cellular infiltration, tissue damage, TNF-α production, and enhanced production of TGF-β.

CONCLUSIONS

Sesquiterpene lactone DPC, isolated from Vernonia scorpioides showed anti-inflammatory activity, in this experimental model of colitis the sesquiterpene lactones DPC and PTH exhibit equal anti-inflammatory activity.

Lipid Transfer Proteins (AaLTP3 and AaLTP4) Are Involved in Sesquiterpene Lactone Secretion from Glandular Trichomes in Artemisia annua

In Artemisia annua plants, glandular trichomes (GTs) are responsible for the biosynthesis and secretion of sesquiterpene lactones including artemisinin/arteannuin B. Nonspecific lipid transfer proteins (LTPs) in plants bind and carry lipid molecules across the cell membrane and are also known as secretary proteins. Interestingly, the transcripts of LTP genes are exceptionally abundant in the GTs of A. annua. In the present study, we isolated two trichome-specific LTP genes (AaLTP3 and AaLTP4) from a Korean ecotype of A. annua. AaLTP3 was expressed abundantly in shoots, whereas AaLTP4 was expressed in flowers. The GUS signal driven by the AaLTP3 or AaLTP4 promoter in transgenic A. annua plants revealed that the AaLTP3 promoter was active on hair-like non-GTs and that the AaLTP4 promoter was active on GTs. Analysis of enhanced cyan fluorescent protein (ECFP) fluorescence fused with the AaLTP3 or AaLTP4 protein in transgenic tobacco revealed that ECFP florescence was very bright on secreted lipids of long GTs. Moreover, the florescence was also bright on the head cells of short trichomes and their secreted granules. Immunoblotting analysis of GT exudates in petioles of A. annua revealed a strong positive signal against the AaLTP4 antibody. Overexpression of AaLTP3 or AaLTP4 in transgenic A. annua plants resulted in enhanced production of sesquiterpene lactones (arteannuin B, artemisinin, dihydroartemisinic acid and artemisinic acid) compared with those of wild type. The present study shows that LTP genes (AaLTP3 or AaLTP4) play important roles in the sequestration and secretion of lipids in GTs of A. annua, which is useful for the enhanced production of sesquiterpene lactones by genetic engineering.

Sesquiterpene lactones from shoot culture of Artemisia aucheri with cytotoxicity against prostate and breast cancer cells

Plant tissue culture is used to grow plant cells, tissues, or organs under sterile and determined conditions on culture media. It is alternative to traditional vegetative propagation, and is applied as an effective technology for the production of valuable secondary metabolites. The Artemisia aucheri (A. aucheri) was obtained from shoot culture grown on MS (Murashige and Skoog 1962) medium. Shade-dried aerial parts of in vitro grown A. aucheri (50 g) were extracted with dichloromethane-acetone (90:10). The extract was submitted for isolation to sephadex gel chromatography and preparative thin layer chromatography, which resulted in identification of one known eudesmanolide named artemin or 2,5-dihydroxy-12, 6-eudesmanolide-4(15)-en for the first time in this plant. In cell cytotoxicity test, artemin showed cytotoxic activity against DU-145,LNCaP prostate cancer, and MCF-7 breast cancer cells with IC₅₀ values of 82.2 ± 5.6, 89.1 ± 6.3 and 111.5 ± 6.7 μM , respectively. Artemin was more active against prostate cancer cells with approximately same cytotoxicity against LNCaP androstane dependent cells and DU 145 which is androstane independent.

Primary targets of the sesquiterpene lactone deoxymikanolide on Trypanosoma cruzi

BACKGROUND

Deoxymikanolide is a sesquiterpene lactone isolated from Mikania micrantha and M. variifolia which, has previously demonstrated in vitro activity on Trypanosoma cruzi and in vivo activity on an infected mouse model.

PURPOSE

Based on these promising findings, the aim of this study was to investigate the mechanism of action of this compound on different parasite targets.

METHODS

The interaction of deoxymikanolide with hemin was examined under reducing and non- reducing conditions by measuring modifications in the Soret absorption band of hemin; the thiol interaction was determined spectrophotometrically through its reaction with 5,5'-dithiobis-2-nitrobenzoate in the presence of glutathione; activity on the parasite antioxidant system was evaluated by measuring the activity of the superoxide dismutase and trypanothione reductase enzymes, together with the intracellular oxidative state by flow cytometry. Superoxide dismutase and trypanothione reductase activities were spectrophotometrically tested. Cell viability, phosphatidylserine exposure and mitochondrial membrane potential were assessed by means of propidium iodide, annexin-V and rhodamine 123 staining, respectively; sterols were qualitatively and quantitatively tested by TLC; ultrastructural changes were analyzed by transmission electron microscopy. Autophagic cells were detected by staining with monodansylcadaverine.

RESULTS

Deoxymikanolide decreased the number of reduced thiol groups within the parasites, which led to their subsequent vulnerability to oxidative stress. Treatment of the parasites with the compound produced a depolarization of the mitochondrial membrane even though the plasma membrane permeabilization was not affected. Deoxymikanolide did not affect the intracellular redox state and so the mitochondrial dysfunction produced by this compound could not be attributed to ROS generation. The antioxidant defense system was affected by deoxymikanolide at twenty four hours of treatment, when both an increased oxidative stress and decreased activity of superoxide dismutase and trypanothione reductase (40 and 60% respectively) were observed. Both the oxidative stress and mitochondrial dysfunction induce parasite death by apoptosis and autophagy.

CONCLUSION

Based on our results, deoxymikanolide would exert its anti-T cruzi activity as a strong thiol blocking agent and by producing mitochondrial dysfunction.

Bioassay-guided isolation and identification of gametocytocidal compounds from Artemisia afra (Asteraceae)

Background

Optimal adoption of the malaria transmission-blocking strategy is currently limited by lack of safe and efficacious drugs. This has sparked the exploration of different sources of drugs in search of transmission-blocking agents. While plant species have been extensively investigated in search of malaria chemotherapeutic agents, comparatively less effort has been channelled towards exploring them in search of transmission-blocking drugs. Artemisia afra (Asteraceae), a prominent feature of South African folk medicine, is used for the treatment of a number of diseases, including malaria. In search of transmission-blocking compounds aimed against Plasmodium parasites, the current study endeavoured to isolate and identify gametocytocidal compounds from A. afra.

Methods

A bioassay-guided isolation approach was adopted wherein a combination of solvent–solvent partitioning and gravity column chromatography was used. Collected fractions were continuously screened in vitro for their ability to inhibit the viability of primarily late-stage gametocytes of Plasmodium falciparum (NF54 strain), using a parasite lactate dehydrogenase assay. Chemical structures of isolated compounds were elucidated using UPLC-MS/MS and NMR data analysis.

Results

Two guaianolide sesquiterpene lactones, 1α,4α-dihydroxybishopsolicepolide and yomogiartemin, were isolated and shown to be active (IC₅₀ < 10 μg/ml; ~ 10 μM) against both gametocytes and intra-erythrocytic asexual P. falciparum parasites. Interestingly, 1α,4α-dihydroxybishopsolicepolide was significantly more potent against late-stage gametocytes than to early-stage gametocytes and intra-erythrocytic asexual P. falciparum parasites. Additionally, both isolated compounds were not overly cytotoxic against HepG2 cells in vitro.

Conclusion

This study provides the first instance of isolated compounds from A. afra against P. falciparum gametocytes as a starting point for further investigations on more plant species in search of transmission-blocking compounds.

Electronic supplementary material

The online version of this article (10.1186/s12936-019-2694-1) contains supplementary material, which is available to authorized users.

Substrate promiscuity of enzymes from the sesquiterpene biosynthetic pathways from Artemisia annua and Tanacetum parthenium allows for novel combinatorial sesquiterpene production

The therapeutic properties of complex terpenes often depend on the stereochemistry of their functional groups. However, stereospecific chemical synthesis of terpenes is challenging. To overcome this challenge, metabolic engineering can be employed using enzymes with suitable stereospecific catalytic activity. Here we used a combinatorial metabolic engineering approach to explore the stereospecific modification activity of the Artemisia annua artemisinic aldehyde ∆11(13) double bond reductase2 (AaDBR2) on products of the feverfew sesquiterpene biosynthesis pathway (GAS, GAO, COS and PTS). This allowed us to produce dihydrocostunolide and dihydroparthenolide. For dihydroparthenolide we demonstrate that the preferred order of biosynthesis of dihydroparthenolide is by reduction of the exocyclic methylene of parthenolide, rather than through C4-C5 epoxidation of dihydrocostunolide. Moreover, we demonstrate a promiscuous activity of feverfew CYP71CB1 on dihydrocostunolide and dihydroparthenolide for the production of 3β-hydroxy-dihydrocostunolide and 3β-hydroxy-dihydroparthenolide, respectively. Combined, these results offer new opportunities for engineering novel sesquiterpene lactones with potentially improved medicinal value.

Tenulin and isotenulin inhibit P-glycoprotein function and overcome multidrug resistance in cancer cells

BACKGROUND

Multidrug resistance (MDR) in cancer is one of the main obstacles in treatment with chemotherapy. Drug efflux through P-glycoprotein is the major mechanism involved in MDR. A potential strategy to provide the best possible clinical outcomes is to develop P-glycoprotein (P-gp) inhibitors from natural products.

PURPOSE

The present study investigated the effects of the natural sesquiterpene lactone tenulin and its derivative isotenulin on human P-gp; the mechanisms of kinetic interactions were also explored.

METHODS

The human P-gp (ABCB1/Flp-In™-293) stable expression cells were established by using the Flp-In™ system. The effects of tenulin and isotenulin on cell viability were evaluated by SRB assays in established cell lines, sensitive cancer cell line (HeLaS3), and resistant cancer cell line (KB-vin). The transporter inhibition ability was evaluated by calcein-AM uptake assays. The P-gp inhibition kinetics of tenulin and isotenulin were evaluated by rhodamine123 and doxorubicin efflux assays. The ATPase activity was evaluated with the Pgp-Glo™ Assay System.

RESULTS

Tenulin and isotenulin significantly inhibited the P-gp efflux function by stimulating P-gp ATPase activity. Tenulin and isotenulin interacted with the effluxes of rhodamine 123 and doxorubicin through a competitive and noncompetitive mechanism, respectively. The combinations of tenulin and isotenulin with chemotherapeutic drugs significantly resensitized MDR cancer cells.

CONCLUSION

These results suggested that tenulin and isotenulin are potential candidates to be developed for synergistic treatment of MDR cancers.

Sesquiterpene lactone from Artemisia argyi induces gastric carcinoma cell apoptosis via activating NADPH oxidase/reactive oxygen species/mitochondrial pathway

Apoptosis is an essential type of programmed cell death. Previous studies have demonstrated that a wide range of natural-derived anticancer agents induce apoptosis by trigging oxidative stress. Artemisia argyi is a traditional Chinese herb for treating diverse diseases including dyspepsia, arthroncus, and anaphylactic disease. In this study, sesquiterpene lactone 3 (SL3), a bioactive ingredient isolated from Artemisia argyi was found to show obvious inhibitory effect on two gastric carcinoma cells. Mechanism study revealed that SL3 promoted the membrane translocation of p47, activated nicotinamide adenine dinucleotide (NADPH) oxidase, and evaluated intracellular reactive oxygen species production, leading to the activation of mitochondria-dependent caspase apoptosis pathway. Collectively, these findings show that SL3 is a promising anticancer candidate against gastric carcinoma by activating NADPH oxidase/reactive oxygen species/mitochondrial pathway.

Application of sesquiterpene lactone: A new promising way for cancer therapy based on anticancer activity

Cancer is one of the most dangerous diseases that are rapidly increasing globally. After heart disease, it is the second leading cause of death, accounting for seven million deaths each year. Chemotherapy is the use of cytotoxic drugs on cancer cells. But the use of common chemotherapy drugs poses a problem due their high side effects and low efficacy. As a result, efforts are on to find new potent compounds with low side effects. The compounds extracted from plants have been studied in this regard due to their prevalence. Sesquiterpene lactones are a group of natural compounds that were first detected in Asteraceae dark plants. These compounds exercise their effects by reacting with functional groups available on proteins and enzymes, especially the thiol group. Owing to the high side effects as an antitumor synthetic drugs, efforts are being made to find drugs with high efficiency and low side effects. Their high structural ranges have attracted the attention of many researchers as a potential source of new anticancer drugs.

QSAR of Natural Sesquiterpene Lactones as Inhibitors of Myb-dependent Gene Expression

BACKGROUND

Protein c-Myb is a therapeutic target. Some sesquiterpene lactones suppress Myb-dependent gene expression, which results in their potential anti-cancer activity.

MATERIAL & METHODS

Database ChEMBL is a representative of lactones for physicochemical and physiochemical properties. Data presented for 31 natural lactones are discussed in terms of quantitative structureactivity relationships with the objective to predict inhibitors of Myb-induced gene expression. Several constitutional descriptors are related to structure-activity. α-Methylene-γ-lactone groups enhance while OH functions worsen potency. The latter feature is in agreement with the fact that the more lipophilic the lactone, the greater the cytotoxicity because of the ability to cross lipoidal biomembranes. In general, numbers of &#960;-systems and atoms, and polarizability enhance activity. Linear and nonlinear structure-activity models are developed, between lactones of a great structural diversity, to predict inhibitors of Myb-induced gene expression. Four variables (ML, UNC, TCO+OCOR, UNC+UNA) related to ATOM show a positive correlation because of the partial anionic and H-acceptor characters of O-atom. In most, CO group is conjugated.

RESULT AND CONCLUSION

Term OH shows negative coefficients because of the partial cationic quality of H-atom and because OH forms H-bonds with CO, causing them to be less H-acceptor. s-trans-s-trans-Germacranolide structure is the most active. Coefficients standard errors result acceptable in almost all equations. After cross-validation, linear equations for lactones, pseudoguaianolides and germacranolides are the most predictive. Most descriptors are constitutional variables.

An Artemisia-derived natural product-based fluorescent probe for the bitter taste receptor hTAS2R38

The discovery of taste receptors hTAS2Rs expression in extra oral tissue, especially in the gastrointestinal tract and in the respiratory system, has endowed bitter receptors of functionalities that exceed the simple perception of taste and flavour. In particular, stimulation of hTAS2Rs by bitter agents in the airway smooth muscle triggers bronchodilation of possible pharmacological relevance. To study the receptor localization in pulmonary smooth muscle cells and to investigate their biological response to hTAS2R38 activation, we have developed a fluorescent probe for hTAS2R38 starting from the sesquiterpene lactone costunolide, available in multigram amounts from Artemisia umbelliformis Lam. The N-methylanthranilate-containing probe demonstrated a very low cytotoxicity compared to the natural product toward human airway smooth muscle cells and epithelial bronchial cells, but fully retained its binding to hTAS2R38, making it possible the fluorescent detection of cells expressing this bitter receptor.

Qualitative HPLC-DAD/ESI-TOF-MS Analysis, Cytotoxic, and Apoptotic Effects of Croatian Endemic Centaurea ragusina L. Aqueous Extracts

Centaurea ragusina L., an endemic Croatian plant species, revealed a good cytotoxic activity of aqueous extracts (AE) on human bladder (T24) and human glioblastoma (A1235) cancer cell lines. The chemical constituents were tentatively identified using high performance liquid chromatography HPLC-DAD/ESI-TOF-MS in negative ionization mode. The main compounds of herba extract were sesquiterpene lactones: solstitialin A 3,13-diacetate and epoxyrepdiolide; organic acid: quinic acid. The main compounds of flower extract were organic acids: quinic acid, citric acid, and malic acid; sesquiterpene lactone: cynaropicrin; phenolic compounds: chlorogenic acid and phenylpropanoid: syringin. The AE of C. ragusina were investigated for correlation of their effects on human bladder (T24) and human glioblastoma (A1235) cancer cell lines using the MTT assay. Although both extracts showed significant dose- and time-dependent cytotoxic activity against both cancer cell lines, the flower extract exhibited slightly higher activity. In order to determine type of cell death induced by treatment, cell lines were exposed subsequently to a treatment with both flower and herba AE. The majority of the cells died by induced apoptosis treatment. Flower AE (26.25%), compared to a leaf AE (22.15%) showed slightly higher percentage of an apoptosis in T24 cells, when compared to a non-treated cells (0.04%).

Sesquiterpene lactone! a promising antioxidant, anticancer and moderate antinociceptive agent from Artemisia macrocephala jacquem

Background

Sesquiterpene lactones (STLs) make a diverse and huge group of bio-active constituents that have been isolated from several plant families. However, the greatest numbers are present in Asteraceae family having more than 3000 different reported structures. Recently several researchers have reported that STLs have significant antioxidant and anticancer potentials.

Methods

To investigate the antioxidant, anticancer and antinociceptive potentials of STLs, gravity column chromatography technique was used for isolation from the biologically rich chloroform fraction of Artemisia macrocephala Jacquem. The antioxidant activity of the isolated STLs was determined by DPPH and ABTS free radical scavenging activity, anticancer activity was determined on 3 T3, HeLa and MCF-7 cells by MTT assay while the antinociceptive activity was determined through acetic acid induced writhings, tail immersion method and formalin induced nociception method.

Results

The results showed that the STLs of Artemisia macrocephala possesses promising antioxidant activity and also it decreased the viability of 3 T3, HeLa and MCF-7 cells and mild to moderate antinociceptive activity.

Conclusion

Sesquiterpenes lactones (STLs) are widely present in numerous genera of the family Asteraceae (compositae). They are described as the active constituents used in traditional medicine for the treatment of various diseases. The present study reveals the significant potentials of STL and may be used as an alternative for the management of cancer. Anyhow, the isolated compound is having no prominent antinociceptive potentials.

Electronic supplementary material

The online version of this article (doi:10.1186/s12906-016-1517-y) contains supplementary material, which is available to authorized users.

Discovery of germacrene A synthases in Barnadesia spinosa: The first committed step in sesquiterpene lactone biosynthesis in the basal member of the Asteraceae

The Andes-endemic Barnadesioideae lineage is the oldest surviving and phylogenetically basal subfamily of the Asteraceae (Compositae), a prolific group of flowering plants with world-wide distribution (∼24,000 species) marked by a rich diversity of sesquiterpene lactones (STLs). Intriguingly, there is no evidence that members of the Barnadesioideae produce STLs, specialized metabolites thought to have contributed to the adaptive success of the Asteraceae family outside South America. The biosynthesis of STLs requires the intimate expression and functional integration of germacrene A synthase (GAS) and germacrene A oxidase (GAO) to sequentially cyclize and oxidize farnesyl diphosphate into the advanced intermediate germacrene A acid leading to diverse STLs. Our previous discovery of GAO activity conserved across all major subfamilies of Asteraceae, including the phylogenetically basal lineage of Barnadesioideae, prompted further investigation of the presence of the gateway GAS in Barnadesioideae. Herein we isolated two terpene synthases (BsGAS1/BsGAS2) from the basal Barnadesia spinosa (Barnadesioideae) that displayed robust GAS activity when reconstituted in yeast and characterized in vitro. Despite the apparent lack of STLs in the Barnadesioideae, this work unambiguously confirms the presence of GAS in the basal genera of the Asteraceae. Phylogenetic analysis reveals that the two BsGASs fall into two distinct clades of the Asteraceae's GASs, and BsGAS1 clade is only retained in the evolutionary closer Cichorioideae subfamily, implicating BsGAS2 is likely the ancestral base of most GASs found in the lineages outside the Barnadesioideae. Taken together, these results show the enzymatic capacities of GAS and GAO emerged prior to the subsequent radiation of STL-producing Asteraceae subfamilies.

Transformation of toxic and allelopathic lantana into a benign organic fertilizer through vermicomposting

In a first study of its kind, the composition of vermicompost derived solely from the toxic and allelopathic weed lantana has been investigated using UV-visible and Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric (TG) and differential scanning calorimetry (DSC), gas chromatography-mass spectometry (GC-MS), and scanning electron microscopy (SEM). The studies reveal that a sharp reduction in humification index, substantial mineralization of organic matter and degradation of complex aromatics such as lignin and polyphenols into simpler carbohydrates and lipids occur in the course of vermicomposting. GC-MS analysis shows significant fragmentation, bio-oxidation and molecular rearrangements of chemical compounds in vermicompost in comparison to those in lantana. SEM micrographs of vermicompost reflect strong disaggregation of material compared to the much better formed lantana matrices. The phenols and sesquiterpene lactones which are specifically responsible for the toxicity and allelopathy of lantana are seen to get significantly degraded in the course of vermicomposting - turning it into a plant-friendly organic fertilizer. The study leads to the possibility that the millions of tons of phytomass that is generated annually by lantana can be gainfully utilized in producing organic fertilizer via vermicomposting.

Identification and Functional Characterization of Sesquiterpene Synthases from Xanthium strumarium

Xanthium strumarium synthesizes various pharmacologically active sesquiterpenes. The molecular characterization of sesquiterpene biosynthesis in X. strumarium has not been reported so far. In this study, the cDNAs coding for three sesquiterpene synthases (designated as XsTPS1, XsTPS2 and XsTPS3) were isolated using the X. strumarium transcriptome that we recently constructed. XsTPS1, XsTPS2 and XsTPS3 were revealed to have primary activities forming germacrene D, guaia-4,6-diene and germacrene A, respectively, by either ectopic expression in yeast cells or purified recombinant protein-based in vitro assays. Quantitative real-time PCRs and metabolite analysis for the different plant parts showed that the transcript abundance of XsTPS1-XsTPS3 is consistent with the accumulation pattern of their enzymatic products, supporting their biochemical functions in vivo. In particular, we discovered that none of the XsTPS2 product, guaia-4,6-diene, can be detected in one of the X. strumarium cultivars used in this study (it was named the Hubei-cultivar), in which a natural deletion of two A bases in the XsTPS2 cDNA disrupts its activity, which further confirmed the proposed biochemical role of XsTPS2 in X. strumarium in vivo.

Molecular mechanism of apoptosis induction by Gaillardin, a sesquiterpene lactone, in breast cancer cell lines : Gaillardin-induced apoptosis in breast cancer cell lines

Medicinal plant extracts have been widely used for cancer treatment. Gaillardin is a natural sesquiterpene lactone that has recently been reported to have anticancer properties. The ability to induce apoptosis is an important property of a candidate anticancer drug, which discriminates between anticancer drugs and toxic compounds. The current study was therefore carried out to address the issue if Gaillardin is able to induce apoptosis in the breast cancer cell lines MCF-7 and MDA-MB-468 and to determine the underlying mechanism of its anticancer effects. Apoptosis induction by Gaillardin treatment was confirmed by annexin V-FITC/PI staining, and caspase-3,-6, and-9 activation. Using Western blot analysis, we found that Gaillardin upregulated the pro-apoptotic protein Bax and p53 and downregulated the anti-apoptotic protein Bcl-2. Moreover, the apoptotic effect of Gaillardin was also related to ROS production and loss of mitochondrial membrane potential (ΔΨm). Taken together, these results demonstrate that Gaillardin can inhibit proliferation of breast cancer cells via inducing mitochondrial apoptotic pathway and therefore, might be a promising molecule in cancer chemoprevention or chemotherapy.

Accumulation of cynaropicrin in globe artichoke and localization of enzymes involved in its biosynthesis

Globe artichoke (Cynara cardunculus var. scolymus) belongs to the Asteraceae family, in which one of the most biologically significant class of secondary metabolites are sesquiterpene lactones (STLs). In globe artichoke the principal STL is the cynaropicrin, which contributes to approximately 80% of its characteristic bitter taste. Cynaropicrin content was assessed in globe artichoke tissues and was observed to accumulate in leaves of different developmental stages. In the receptacle, a progressive decrease was observed during inflorescence development, while the STL could not be detected in the inflorescence bracts. Almost undetectable amounts were found in the roots and inflorescence stems at the commercial stage. Cynaropicrin content was found to correlate with expression of genes encoding CcGAS, CcGAO and CcCOS, which are involved in the STL biosynthesis. A more detailed study of leaf material revealed that cynaropicrin predominantly accumulates in the trichomes, and not in the apoplastic cavity fluids. Analysis of the promoter regions of CcGAO and CcCOS revealed the presence of L1-box motifs, which confers trichome-specific expression in Arabidopsis, suggesting that cynaropicrin is not only stored but also synthesized in trichomes. A transient expression of GFP fusion proteins was performed in Nicotiana benthamiana plants: the CcGAS fluorescence signal was located in the cytoplasm while the CcGAO and CcCOS localized to the endoplasmatic reticulum.

Synthesis, cytotoxicity and inhibition of NO production of ivangustin enantiomer analogues

The eight novel ivangustin enantiomer analogues possessing α-methylene-γ-butyrolactone moiety have been synthesized using (4S6R, 4S6S)-4-tert-butyldimethylsilyloxy-6-methylcyclohex-2-en-1-one (1) as starting material. These transformations were mainly carried out by aldol condensation reaction and one-pot annelation procedure. The stereochemistry of these synthesized analogues was determined by NOE analysis. Their cytoxicity was evaluated against the human cancer cell lines HCT-116 (colon), HL-60 (leukemia), QGY-7701 (liver), SMMC-7721 (liver), A549 (lung), MCF-7 (breast). The results showed that these analogues were more selective against the cell lines HL-60 and QGY-7701. Analogue 17 exhibited potent cytotoxicity and high selectivity toward HL-60 cell line with IC50 value of 1.02 μM, which suggested that it might be a promising anti-cancer lead compound. The inhibitory activities against NO production and the cytotoxicities in RAW 264.7 macrophages were determined at the same time. All of the analogues significantly inhibited the NO production with IC50 value in the range of 3.44-6.99 μM. Analogues 17, 22, 23 and 7 showed higher cytotoxicities, indicated their inhibitory activities against NO production may be influenced by the cytotoxicities.