Sesquiterpenoids from Tussilago farfara inhibit LPS-induced nitric oxide production in macrophage RAW 264.7 cells

Structurally diverse new eudesmane sesquiterpenoids with anti-inflammatory activity from the fruits of Alpinia oxyphylla

The phytochemical investigation of the fruits of Alpinia oxyphylla led to the isolation and identification of 40 structurally diverse sesquiterpenoids, including 17 new eudesmane sesquiterpenoids (1-17) and 23 known analogues (18-40). Among the isolates, 14 and 17 were unusual rearranged eudesmane sesquiterpenoids, featuring rare 5/6-fused and 6/8-fused bicyclic carbon skeleton, respectively; 15 and 16 were the novel 6,7-seco-eudesmane sesquiterpenoids isolated from plant-origin for the first time, 1 and 3-6 were rare nor-eudesmane sesquiterpenoids. Their structures were elucidated by comprehensive spectroscopic data analysis (NMR, HRESIMS, IR, UV), single crystal X-ray diffraction, and quantum chemistry calculations (ECD and ¹³C NMR). Moreover, all isolates were evaluated by measuring their inhibitory effect on nitric oxide (NO) in LPS-stimulated BV-2 cells. As a result, compounds 11, 20, 24 and 40 showed moderate to strong inhibition on NO productions, with IC₅₀ values ranging from 21.63 to 60.70 μM. Meanwhile, these compounds also partially decreased the secretion of TNF-α and IL-6 in LPS-stimulated BV-2 cells. Furthermore, 20 could down-regulate protein expressions (COX-2 and iNOS) and observably inhibit the mRNA expressions of TNF-α, IL-6, COX-2 and iNOS. In this study, the discovery of structurally diverse anti-inflammatory sesquiterpenoids from the fruits of A. oxyphylla could benefit the further development and utilization of this plant.

A Comparative Analysis of the Anatomy, Phenolic Profile, and Antioxidant Capacity of Tussilago farfara L. Vegetative Organs

Tussilago farfara L., a perennial species, is a medicinal herb used in traditional medicine, mainly for the treatment of respiratory tract-related pathology. In traditional Chinese medicine, flower buds are preferred; in Europe, the leaves are used; and in some parts of India, the whole plant is utilized. This preferential usage of the plant organs might be based on differences in the chemical composition due to environmental conditions, along with preferred traditional and cultural approaches. In this article, the impact of pedoclimatic growth conditions on the morpho-anatomical development and phytochemical profile of the plant were studied on T. farfara in the vegetative state, collected from two different locations in the Romanian spontaneous flora, revealing significant variations. Furthermore, the antioxidant profile of the specific extracts from the aerial and subterranean plant parts is also in accordance with these discrepancies. The plant anatomy was assessed histologically by optical microscopy, while the analytical chemistry evaluation was based on LC/MS and spectral methods for the evaluation of the antioxidant and enzyme inhibitory activity. To our knowledge, this is the first comparative analysis contextually reporting on the histology, phenolic profile, antioxidant capacity, and geographical location of the vegetative form of T. farfara.

Bisabolane-type sesquiterpenoids: Structural diversity and biological activity

Bisabolane-type sesquiterpenoids, a class of monocyclic sesquiterpenoids, are widely distributed in nature and have a variety of biological activities. To provide a reference for the further research and development of these compounds, the phytochemical and biological properties of natural bisabolane-type sesquiterpenoids (356 compounds in total) isolated between 1985 and 2020 from 24 families, primarily Compositae, Zingiberaceae, Aspergillaceae, Halichondriidae, and Aplysiidae were reviewed. In vitro and in vivo studies have indicated that antibacterial, anti-inflammatory, and cytotoxic effects are the most commonly reported pharmacological properties of bisabolane-type sesquiterpenoids. Owing to their extensive significant effects, a lot of traditional medicines containing this type of compounds have been used for a long history. Thus, bisabolane-type sesquiterpenoids are a rich source of important natural products, which show great potential for the development of new drugs.

A review of the ethnobotanical value, phytochemistry, pharmacology, toxicity and quality control of Tussilago farfara L. (coltsfoot)

ETHNOPHARMACOLOGICAL RELEVANCE

Tussilago farfara L. (commonly called coltsfoot), known as a vital folk medicine, have long been used to treat various respiratory disorders and consumed as a vegetable in many parts of the world since ancient times.

AIM OF THE REVIEW

This review aims to provide a critical evaluation of the current knowledge on the ethnobotanical value, phytochemistry, pharmacology, toxicity and quality control of coltsfoot, thus provide a basis for further investigations.

MATERIALS AND METHODS

A detailed literature search was obtained using various online search engines (e.g. Google Scholar, Web of Science, Science Direct, Baidu Scholar, PubMed and CNKI). Additional information was sourced from ethnobotanical literature focusing on Chinese and European flora. The plant synonyms were validated by the database 'The Plant List' (www.theplantlist.org).

RESULTS

Coltsfoot has diverse uses in local and traditional medicine, but similarities have been noticed, specifically for relieving inflammatory conditions, respiratory and infectious diseases in humans. Regarding its pharmacological activities, many traditional uses of coltsfoot are supported by modern in vitro or in vivo pharmacological studies such as anti-inflammatory activities, neuro-protective activity, anti-diabetic, anti-oxidant activity. Quantitative analysis (e.g. GC-MS, UHPLC-MRM^HR) indicated the presence of a rich (>150) pool of chemicals, including sesquiterpenes, phenolic acids, flavonoids, chromones, pyrrolizidine alkaloids (PAs) and others from its leaves and buds. In addition, adverse events have resulted from a collection of the wrong plant which contains PAs that became the subject of public concern attributed to their highly toxic.

CONCLUSIONS

So far, remarkable progress has been witnessed in phytochemistry and pharmacology of coltsfoot. Thus, some traditional uses have been well supported and clarified by modern pharmacological studies. Discovery of therapeutic natural products and novel structures in plants for future clinical and experimental studies are still a growing interest. Furthermore, well-designed studies in vitro particularly in vivo are required to establish links between the traditional uses and bioactivities, as well as ensure safety before clinical use. In addition, the good botanical identification of coltsfoot and content of morphologically close species is a precondition for quality supervision and control. Moreover, strict quality control measures are required in the studies investigating any aspect of the pharmacology and chemistry of coltsfoot.

Chemical comparison of the raw and processed Farfarae Flos by liquid chromatography-mass spectrometry based metabolomic approach

Farfarae Flos (FF) has been used in China for a long time as an anti-tussive and expectorant herbal drugs, and it was usually honey-fried FF (HFF). To clarify the mechanism of honey processing, it is important to know the chemical difference between FF and HFF firstly. In this study, UHPLC-Orbitrap-MS was used to characterize the chemical compounds in FF, honey and HFF. Then the metabolomic approach based on UHPLC-Orbitrap-MS revealed 68 differential compounds between the FF and HFF, and chemical reactions occurring during processing were also proposed to elucidate the honey processing mechanisms of FF. In order to investigate the chemical difference between FF and HFF comprehensively and accurately, the components derived from the honey and the moisture content in FF and HFF were considered for the first time. In summary, this study investigated the chemical differences between FF and HFF in a holistic way, which laid the basis for the quality control of HFF and further explaining the honey processing mechanisms of FF. In addition, eight native compounds derived from the honey could be used as the index to authenticate the HFF prepared by the genuine honey.

7β-(3-Ethyl-cis-crotonoyloxy)-1α-(2-methylbutyryloxy)-3,14-dehydro-Z Notonipetranone Attenuates Neuropathic Pain by Suppressing Oxidative Stress, Inflammatory and Pro-Apoptotic Protein Expressions

7β-(3-Ethyl-cis-crotonoyloxy)-1α-(2-methylbutyryloxy)-3,14-dehydro-Z-notonipetranone (ECN), a sesquiterpenoid obtained from a natural source has proved to be effective in minimizing various side effects associated with opioids and nonsteroidal anti-inflammatory drugs. The current study focused on investigating the effects of ECN on neuropathic pain induced by partial sciatic nerve ligation (PSNL) by mainly focusing on oxidative stress, inflammatory and apoptotic proteins expression in mice. ECN (1 and 10 mg/kg, i.p.), was administered once daily for 11 days, starting from the third day after surgery. ECN post-treatment was found to reduce hyperalgesia and allodynia in a dose-dependent manner. ECN remarkably reversed the histopathological abnormalities associated with oxidative stress, apoptosis and inflammation. Furthermore, ECN prevented the suppression of antioxidants (glutathione, glutathione-S-transferase, catalase, superoxide dismutase, NF-E2-related factor-2 (Nrf2), hemeoxygenase-1 and NAD(P)H: quinone oxidoreductase) by PSNL. Moreover, pro-inflammatory cytokines (tumor necrotic factor-alpha, interleukin 1 beta, interleukin 6, cyclooxygenase-2 and inducible nitric oxide synthase) expression was reduced by ECN administration. Treatment with ECN was successful in reducing the caspase-3 level consistent with the observed modulation of pro-apoptotic proteins. Additionally, ECN showed a protective effect on the lipid content of myelin sheath as evident from FTIR spectroscopy which showed the shift of lipid component bands to higher values. Thus, the anti-neuropathic potential of ECN might be due to the inhibition of oxidative stress, inflammatory mediators and pro-apoptotic proteins.

Farfarae Flos: A review of botany, traditional uses, phytochemistry, pharmacology, and toxicology

ETHNOPHARMACOLOGICAL RELEVANCE

Farfarae Flos (FF; dried flower buds of Tussilago farfara L.), a widely used traditional Chinese medicine (TCM), is also known as "Kuandonghua" (Chinese: ). It has a wide range of pharmacological effects and has long been used to treat various respiratory conditions including cough, asthma, and acute or chronic bronchitis.

AIMS

This study reviews the current advances in the research on the botany, ethnopharmacology, phytochemistry, pharmacology, and toxicology of Farfarae Flos. Prospects for future investigation and application of this herb are also discussed.

MATERIALS AND METHODS

Information on FF was collected from both published materials (such as ancient and modern books, Ph.D. and M. Sc. dissertations, monographs on medicinal plants, and pharmacopoeia) and electronic databases (such as CNKI, SciFinder, WanFang data, PubMed, ScienceDirect, Web of Science, Taylor&Francis, ACS Publications, Wiley, Springer, Europe PMC, EBSCOhost, J-STAGE, and Google Scholar).

RESULTS

Approximately 175 chemical compounds, including terpenoids, organic acids, flavonoids, alkaloids, chromones, volatile oils, and other compounds, have been isolated from FF. This TCM has been reported to produce pharmacological effects on the respiratory, cardiovascular, and digestive systems, and exert antioxidant, anti-inflammatory, and neuroprotective activities. FF is safe in the traditional dose range, but the potential toxicity due to the emergence of pyrrolidine alkaloids needs to be paid more attention.

CONCLUSIONS

FF is a commonly used TCM with pharmacological activities mainly on the respiratory system. This study suggests that the further expansion of the pharmacological effect of FF and in-depth study of its prescription need to be concerned about. The investigations of the role of more active substances and the pharmacokinetics of the hepatotoxic components of FF will help to maximize the therapeutic potential and promote its popularization and application. Meanwhile, it is important to pay attention to pursue research on the similarities and differences between the leaves and the flower buds to find their respective advantages and make rational use of T. farfara L.

Anti-β-amyloid aggregation activity of enantiomeric furolactone-type lignans from Archidendron clypearia (Jack) I.C.N

The phytochemical investigation on the twigs and leaves of Archidendron clypearia (Jack) I.C.N. led to the isolation of three pairs of furolactone-type lignans enantiomers, including a pair of new compounds (1R,5S,6S)-Kachiranol (1a) and (1S,5R,6R)-Kachiranol (1b) and four known compounds (2a/2b and 3a/3b). Separation of the furolactone-type lignans enantiomeric mixtures was achieved using chiral HPLC for the first time. Their structures were determined by spectroscopic analysis and comparison between the experimental and calculated electronic circular dichroism (ECD) spectra. All optical pure compounds were evaluated for their inhibitory effects on β-amyloid aggregation by ThT assay. Among them, the inhibitory activity of the compound 1b (71.1%) was higher than the positive control (61.0%) and other compounds. In addition, molecular dynamics and molecular docking were employed to explore the binding relationship between the ligand and the receptor.

Biologically active compounds from two members of the Asteraceae family: Tragopogon dubius Scop. and Tussilago farfara L

Tragopogon dubius and Tussilago farfara are consumed as vegetables and used in folk medicine to manage common diseases. Herein, the chemical compositions and biological activities of different leaf extracts (ethyl acetate, methanol, and water) of T. dubius and T. farfara were evaluated. The antibacterial, antifungal, and antioxidant abilities of the extracts were tested using different assays including free radical scavenging, reducing power, phosphomolybdenum, and metal chelating assays. Enzyme inhibitory potentials were evaluated against cholinesterases, tyrosinase, α-amylase and α-glucosidase. Complexes of bioactive compounds (chlorogenic and rosmarinic acid) were docked into the enzymatic cavity of α-glucosidase and subjected to molecular dynamic calculation, enzyme conformational stability, and flexibility analysis. T. dubius and T. farfara extracts showed remarkable antioxidant potentials. Ethyl acetate extracts of T. dubius and T. farfara were the most potent inhibitors of acetylcholinesterase and butyrylcholinesterase. T. dubius ethyl acetate extract and T. farfara methanolic extract showed noteworthy activity against α-glucosidase. High performance liquid chromatography analysis revealed the abundance of some phenolic compounds including chlorogenic and rosmarinic acids. Ethyl acetate extract of T. dubius showed notable antifungal activity against all strains. Docking studies showed best pose for chlorogenic acid was stabilized by a network of hydrogen bonds with residues Asp1157, Asp1279, whereas rosmarinic acid showed several hydrogen bonds with Asp1157, Asp1420, Asp1526, Lys1460 and Trp1369. This study further validates the use of T. dubius and T. farfara in traditional medicine, as well as act as a stimulus for further studies for future biomedicine development. Communicated by Ramaswamy H. Sarma.

A Sesquiterpenoid from Farfarae Flos Induces Apoptosis of MDA-MB-231 Human Breast Cancer Cells through Inhibition of JAK-STAT3 Signaling

Triple-negative breast cancers (TNBCs) are hard-to-treat breast tumors with poor prognosis, which need to be treated by chemotherapy. Signal transducer and activator of transcription 3 (STAT3) is a transcription factor involved in proliferation, metastasis, and invasion of cancer cells. Therefore, research on searching for promising compounds with metabolism that suppress phosphorylation or transcription of STAT3 in TNBC cells is important. Farfarae Flos is well known as a traditional medicine for treating inflammation. However, few studies have shown that sesquiterpenoids from Farfarae Flos have an anticancer effect. In this study, efficient separation methods and an MTT assay were conducted to isolate an anticancer compound from Farfarae Flos against TNBC MDA-MB-231 cells. Here, 7β-(3-Ethyl-cis-crotonoyloxy)-1α-(2-methylbutyryloxy)-3,14-dehydro-Z-notonipetranone (ECN), a compound isolated from Farfarae Flos showed a potent cytotoxic effect on MDA-MB-231 cells. ECN inhibited JAK–STAT3 signaling and suppressed the expression of STAT3 target genes. In addition, ECN induced apoptosis through both extrinsic and intrinsic pathways. Furthermore, we investigated that ECN inhibited the growth of tumors by intraperitoneal administration in mice injected with MDA-MB-231 cells. Therefore, ECN can be an effective chemotherapeutic agent for breast cancer treatment.

Sesquiterpenoids from Tussilago farfara Flower Bud Extract for the Eco-Friendly Synthesis of Silver and Gold Nanoparticles Possessing Antibacterial and Anticancer Activities

Sesquiterpenoids from the flower bud extract of Tussilago farfara were effectively utilized as a reducing agent for eco-friendly synthesis of silver and gold nanoparticles. The silver and gold nanoparticles had a characteristic surface plasmon resonance at 416 nm and 538 nm, respectively. Microscopic images revealed that both nanoparticles were spherical, and their size was measured to be 13.57 ± 3.26 nm for the silver nanoparticles and 18.20 ± 4.11 nm for the gold nanoparticles. The crystal structure was determined to be face-centered cubic by X-ray diffraction. Colloidal stability of the nanoparticle solution was retained in a full medium, which was used in the cell culture experiment. The antibacterial activity result demonstrated that the silver nanoparticles showed better activity (two- to four-fold enhancement) than the extract alone on both Gram-positive and Gram-negative bacteria. Interestingly, the highest antibacterial activity was obtained against vancomycin-resistant Enterococci Van-A type Enterococcus faecium. Cytotoxicity on cancer cell lines confirmed that gold nanoparticles were more cytotoxic than silver nanoparticles. The highest cytotoxicity was observed on human pancreas ductal adenocarcinoma cells. Therefore, both nanoparticles synthesized with the sesquiterpenoids from T. farfara flower bud extract can be applicable as drug delivery vehicles of anticancer or antibacterial agents for future nanomedicine applications.

Effects of Flower Buds Extract of Tussilago farfara on Focal Cerebral Ischemia in Rats and Inflammatory Response in BV2 Microglia

OBJECTIVE

To investigate the effects of the flower buds extract of Tussilago farfara Linné (Farfarae Flos; FF) on focal cerebral ischemia through regulation of inflammatory responses in activated microglia.

METHODS

Brain ischemia was induced in Sprague-Dawley rats by a transient middle cerebral artery occlusion (tMCAO) for 90 min and reperfusion for 24 h. Twenty rats were randomly divided into 4 groups (n=5 per group): normal, tMCAO-induced ischemic control, tMCAO plus FF extract 300 mg/kg-treated, and tMCAO plus MK-801 1 mg/kg-treated as reference drug. FF extract (300 mg/kg, p.o.) or MK-801 (1 mg/kg, i.p.) was administered after reperfusion. Brain infarction was measured by 2,3,5,-triphenyltetrazolium chloride staining. Neuronal damage was observed by haematoxylin eosin, Nissl staining and immunohistochemistry using anti-neuronal nuclei (NeuN), anti-glial fibrillary acidic protein (GFAP), and anti-CD11b/c (OX42) antibodies in ischemic brain. The expressions of inducible nitric oxide synthase (iNOS), tumor necrosis factor (TNF-α), and hypoxia-inducible factor-1a (HIF-1α) were determined by Western blot. BV2 microglial cells were treated with FF extract or its main bioactive compound, tussilagone with or without lipopolysaccharide (LPS). Nitric oxide (NO) production was measured in culture medium by Griess assay. The expressions of iNOS, COX-2 and pro-inflammatory cytokines mRNA were analyzed by reverse transcription-polymerase chain reaction. The expression of iNOS, and COX-2 proteins, the phosphorylation of ERK1/2, JNK, and p38 MAPK and the nuclear expression of NF-κB p65 in BV2 cells were determined by Western blot.

RESULTS

FF extract significantly decreased brain infarctions in ischemic rats (P<0.01). The neuronal death and the microglia/astrocytes activation in ischemic brains were inhibited by FF extract. FF extract also suppressed iNOS, TNF-α, and HIF-1α expression in ischemic brains. FF extract (0.2 and 0.5 mg/mL, P<0.01) and tussilagone 20 and 50 μmol/L, P<0.01) significantly decreased LPS-induced NO production in BV2 microglia through downregulation of iNOS mRNA and protein expression. FF extract and tussilagone significantly inhibited LPS-induced expression of TNF-α, IL-1β, and IL-6 mRNA, and also suppressed the phosphorylation of ERK1/2, JNK and p38 MAPK and the nuclear expression of NF-κB in a dose-dependent manner.

CONCLUSIONS

FF extract has a neuroprotective effect in ischemic stroke by the decrease of brain infarction, and the inhibition of neuronal death and microglial activation-mediated inflammatory responses.

Inhibitory effect of ethanol extract of Nannochloropsis oceanica on lipopolysaccharide-induced neuroinflammation, oxidative stress, amyloidogenesis and memory impairment

Oxidative stress and neuroinflammation is implicated in the pathogenesis and development of Alzheimer's disease (AD). Here, we investigated the suppressive possibility of ethanol extract of Nannochloropsis oceanica (N. oceanica) on memory deficiency along with the fundamental mechanisms in lipopolysaccharide (LPS)-treated mice model. Among several extracts of 32 marine microalgae, ethanol extract of N. oceanica showed the most significant inhibitory effect on nitric oxide (NO) generation, NF-κB activity and β-secretase activity in cultured BV-2 cells, neuronal cells and Raw 264.7 cells. Ethanol extract of N. oceanica (50, 100 mg/kg) also ameliorated LPS (250 μg/kg)-induced memory impairment. We also found that ethanol extract of N. oceanica inhibited the LPS-induced expression of iNOS and COX-2. Furthermore, the production of reactive oxygen species (ROS), malondialdehyde (MDA) level as well as glutathione (GSH) level was also decreased by treatment of ethanol extract of N.oceanica. The ethanol extract of N. oceanica also suppresses IκB degradation as well as p50 and p65 translocation into the nucleus in LPS-treated mice brain. Associated with the inhibitory effect on neuroinflammation and oxidative stress, ethanol extract of N. oceanica suppressed Aβ1-42 generation through down-regulation of APP and BACE1 expression in in vivo. These results suggest that ethanol extract of N. oceanica ameliorated memory impairment via anti-inflammatory, anti-oxidant and anti-amyloidogenic mechanisms.

Monoterpene esters and aporphine alkaloids from Illigera aromatica with inhibitory effects against cholinesterase and NO production in LPS-stimulated RAW264.7 macrophages

Three new monoterpene phenylpropionic acid esters, illigerates A-C (1-3), and one new aporphine alkaloid, illigeranine (4), as well as four known ones, actinodaphnine (5), nordicentrine (6), 8-hydroxy carvacrol (7), and 3-hydroxy-α,4-dimethyl styrene (8), were isolated from the tubers of Illigera aromatica. The structures of 1-4 were identified by HRESIMS, 1D and 2D NMR, and electronic circular dichroism spectra. Compound 1 potently inhibited NO production in LPS-stimulated RAW264.7 cells with an IC₅₀ value of 18.71 ± 0.85 μM; compound 1, 3, and 4 showed moderate butyrylcholinesterase inhibitory activities with the IC₅₀ values of 46.86 ± 0.65, 53.51 ± 0.71, and 31.62 ± 1.15 μM, respectively. Compound 4 showed weak AChE inhibitory activity with an IC₅₀ value of 81.69 ± 2.07 μM, and compounds 5 and 6 possessed moderate AChE inhibitory activities with the IC₅₀ values of 47.74 ± 1.66 and 40.28 ± 2.73 μM, respectively. This paper provides a chemical structure and bioactive foundation for using I. aromatica as an herbal medicine.