Quantification of Sesquiterpene Lactones in Asteraceae Plant Extracts: Evaluation of their Allergenic Potential

Costunosides A-C: cytotoxic sesquiterpene lactones from the rhizomes of Aucklandia costus Falc

Three new eudesmane type rare sesquiterpene lactone galactosides, costunosides A-C (1-3) were isolated from the rhizomes of Aucklandia costus along with ten known compounds (4-13). Costunosides A-C (1-3) are the first example of naturally eudesmane glycosides containing a β-galactopyranoside moiety. The structure and relative configurations of these compounds were established by comprehensive analysis of MS and, in particular 1D/2D NMR spectroscopic data. The isolated compounds were tested against a panel of human cancer cell lines, where compounds 3, 6 and 7 have shown promising cytotoxic activity against PC-3, HCT-116 and A549 cell lines with IC50 values in the range of 3.4 µM to 9.3 µM, respectively. Costunosides A-C (1-3) were also screened for inhibition assay of acetyl-cholinesterase (AChE), and butyrylcholinesterase (BChE) and found inactive at a concentration of 10 µM.

Contact Sensitization to Allergens of Biological Origin from the Compositae Family and Original Extracts of Ubiquitous Weed Plants of Vojvodina among Patients with Chronic Venous Insufficiency

Background

The use of alternative treatment methods, particularly medicinal herbs from the family Compositae, significantly contributes to the increase in the incidence of allergic contact dermatitis among patients with chronic venous insufficiency.

Objective

Estimating frequency of contact sensitization among patients with chronic venous insufficiency and determining the most common contact sensitizers from the series of bio-origin allergens from the Compositae family and ubiquitous weeds of Vojvodina.

Materials and Methods

The total number of 266 patients with suspected contact dermatitis was divided into two groups: the experimental group consisted of patients with chronic venous insufficiency (EG), and the control group consisted of patients without chronic venous insufficiency (CG). All subjects were tested with allergens of biological origin from the family Compositae, screening allergen SL-mix and original extracts of ubiquitous weed plants of Vojvodina.

Results

Patch test revealed a positive reaction to allergens of the Compositae family in 6.69% in the experimental group, and in 4.17% in the control group. The standardized response rate to the SL-mix in the experimental group was 2.07%, while in the control group, it was 1.51%. The presence of a positive reaction to at least one extract of ubiquitous weed plants of Vojvodina was determined in 6.11% in the experimental group, and in 3.23% of patients in the control group. No statistically significant difference in response rates was found between the examined groups.

Conclusions

Establishing the diagnosis of Compositae dermatitis can be supplemented by additional testing with weed plant extracts from a specific geographical area, resulting in the detection of novel unknown allergens.

Arnica montana Cell Culture Establishment, and Assessment of Its Cytotoxic, Antibacterial, α-Amylase Inhibitor, and Antioxidant In Vitro Bioactivities

Arnica montana cell suspension culture could be a sustainable source of a vegetal material producer of secondary metabolites (SMs) possessing biological effects. Different plant growth regulator concentrations (0-5 mg/L) were tested in foliar explants to induce a callus that was used to establish a cell suspension culture. Growth kinetics was carried out for 30 days. A methanolic extract obtained from biomass harvested at 30 days of growth kinetics was fractionated, and three fractions were tested for bioactivities. We induced a callus with 1 mg/L of picloram and 0.5 mg/L of kinetin in foliar explants, which allowed for the establishment of a cell suspension culture, and the latter had the highest total SMs contents at day 30. Three fractions showed differences in total SMs contents, with the highest values per gram as follows: 270 mg gallic acid equivalent for total phenolic content, 200 mg quercetin equivalent for total flavonoid content, 83 mg verbascoside equivalent for total phenolic acid content, and 396 mg parthenolide equivalent for total sesquiterpene lactone content. The best bioactivities were 2-6 µg/mL for the 50% inhibition of 2,2-diphenyl-1-picrylhydrazyl radical, 30% cellular viability of lymphoma cells at 40 µg/mL, 17% inhibition against Escherichia coli and Staphylococcus aureus at 8 µg/disk, and α-amylase inhibition at 12% with 10 µg/mL. The total SMs contents were correlated with bioactivities.

Asteraceae species as potential environmental factors of allergy

The statistics from Europe and the USA have proven a high risk for skin diseases associated with plant contact. Therefore, plant-induced dermatitis is of increasing attention in dermatology. The focus of this paper was to present the current knowledge on aspects of contact allergy related to Asteraceae (Compositae) species. The Asteraceae family is one of the largest in the world with members across all continents. The PubMed/Medline databases have been searched. The Asteraceae representatives consist of diverse secondary metabolites, which exhibit various advantageous effects in humans. In particular, sesquiterpene lactones (SLs) may cause sensitization resulting in skin irritation and inflammation. In this study, we tried to reveal the allergenic potential of several Asteraceae species. The Asteraceae-related allergy symptoms involve eczema, hay fever, asthma, or even anaphylaxis. Furthermore, the evidence of severe cross-reactivity with food and pollen allergens (PFS) in patients sensitive to Asteraceae allergens have been announced. Further identification and characterization of secondary metabolites and possible allergens in Asteraceae are necessary for the better understanding of Asteraceae-related immune response. The Asteraceae allergy screening panel (the SL mix and the Compositae mix of five plant species) is a promising tool to improve allergy diagnostics and therapy.

Anti-allergic effects of sesquiterpene lactones from Saussurea costus (Falc.) Lipsch. determined using in vivo and in vitro experiments

ETHNOPHARMACOLOGICAL RELEVANCE

Saussurea costus (Falc.) Lipsch. root has been used in Asian traditional medicine for the treatment of asthma, rheumatism, and other conditions. S. costus extracts were shown to alleviate house dust mite-induced atopic-like dermatitis in Nc/Nga mice; besides, sesquiterpene lactones were isolated from S. costus extracts.

AIMS OF THE STUDY

We aimed to investigate the effects of sesquiterpene lactones (alantolactone, costunolide, and dehydrocostuslactone) in allergic asthma using female Balb/c mice and rat RBL-2H3 mast cells.

MATERIALS AND METHODS

Antigen-induced degranulation was assessed by measuring β-hexosaminidase activity in vitro. In addition, a murine ovalbumin-induced allergic asthma model was used to test the in vivo efficacy of sesquiterpene lactones.

RESULTS

Sesquiterpene lactones inhibited antigen-induced degranulation, wherein dehydrocostuslactone > costunolide > alantolactone in potency. Administration of sesquiterpene lactones decreased the number of immune cells, particularly eosinophils, and reduced the expression and secretion of Th2 cytokines (IL-4 and IL-13) in the bronchoalveolar lavage fluid and lung tissues of mice with ovalbumin-induced allergic asthma. Histological studies showed that sesquiterpene lactones reduced inflammation and mucin production in the lungs. Similar to the in vitro study, dehydrocostuslactone showed the highest potency, followed by costunolide and alantolactone.

CONCLUSION

These findings provide evidence that sesquiterpene lactones might be potential anti-allergic therapeutics.

Secondary Metabolites in Allergic Plant Pollen Samples Modulate Afferent Neurons and Murine Tracheal Rings

Plant pollens are strong airborne elicitors of asthma. Their proteinaceous allergens have been studied intensively, but little is known about a possible contribution of pollen secondary metabolites to the nonallergic exacerbation of asthma. Pollen samples originating from 30 plant species were analyzed by HPLC coupled to PDA, ESIMS, and ELSD detectors and off-line NMR spectroscopy. Polyamine conjugates, flavonoids, and sesquiterpene lactones were identified. Polyamine conjugates were characteristic of all Asteraceae species. The presence of sesquiterpene lactones in Asteraceae pollen varied between species and pollen lots. All plant pollen, including those from non-Asteraceae species, contained to some extent electrophiles as determined by their reaction with N-acetyl-l-cysteine. Selected pollen extracts and pure compounds were tested in murine afferent neurons and in murine tracheal preparations. Tetrahydrofuran extracts of Ambrosia artemisiifolia and Ambrosia psilostachya pollen and a mixture of sesquiterpene lactones coronopilin/parthenin increased the intracellular Ca²⁺ concentration in 15%, 32%, and 37% of cinnamaldehyde-responsive neurons, respectively. In organ bath experiments, only the sesquiterpene lactones tested induced a weak dilatation of naïve tracheas and strongly lowered the maximal methacholine-induced tracheal constriction. A tetrahydrofuran extract of A. psilostachya and coronopilin/parthenin led to a time-dependent relaxation of the methacholine-preconstricted trachea. These results provide the first evidence for a potential role of pollen secondary metabolites in the modulation of the tracheal tone.

Grasslands: A Source of Secondary Metabolites for Livestock Health

The need for environmentally friendly practices in animal husbandry, in conjunction with the reduction of the use of synthetic chemicals, leads us to reconsider our agricultural production systems. In that context, grassland secondary metabolites (GSMs) could offer an alternative way to support to livestock health. In fact, grasslands, especially those with high dicotyledonous plant species, present a large, pharmacologically active reservoir of secondary metabolites (e.g., phenolic compounds, alkaloids, saponins, terpenoids, carotenoids, and quinones). These molecules have activities that could improve or deteriorate health and production. This Review presents the main families of GSMs and uses examples to describe their known impact on animal health in husbandry. Techniques involved for their study are also described. A particular focus is put on anti-oxidant activities of GSMs. In fact, numerous husbandry pathologies, such as inflammation, are linked to oxidative stress and can be managed by a diet rich in anti-oxidants. The different approaches and techniques used to evaluate grassland quality for livestock health highlight the lack of efficient and reliable technics to study the activities of this complex phytococktail. Better knowledge and management of this animal health resource constitute a new multidisciplinary research field and a challenge to maintain and valorize grasslands.

Development of Anticancer Agents from Plant-Derived Sesquiterpene Lactones

Sesquiterpene lactones are of considerable interest due to their potent bioactivities, including cancer cell cytotoxicity and antineoplastic efficacy in in vivo studies. Among these compounds, artesunate, dimethylaminoparthenolide, and L12ADT peptide prodrug, a derivative of thapsigargin, are being evaluated in the current cancer clinical or preclinical trials. Based on the structures of several antitumor sesquiterpene lactones, a number of analogues showing greater potency have been either isolated as natural products or partially synthesized, and some potential anticancer agents that have emerged from this group of lead compounds have been investigated extensively. The present review focuses on artemisinin, parthenolide, thapsigargin, and their naturally occurring or synthetic analogues showing potential anticancer activity. This provides an overview of the advances in the development of these types of sesquiterpene lactones as potential anticancer agents, including their structural characterization, synthesis and synthetic modification, and antitumor potential, with the mechanism of action and structure-activity relationships also discussed. It is hoped that this will be helpful in stimulating the further interest in developing sesquiterpene lactones and their derivatives as new anticancer agents.

Natural product HTP screening for antibacterial (E.coli 0157:H7) and anti-inflammatory agents in (LPS from E. coli O111:B4) activated macrophages and microglial cells; focus on sepsis

Background

Acute systemic inflammatory response syndrome arising from infection can lead to multiple organ failure and death, with greater susceptibility occurring in immunocompromised individuals. Moreover, sub-acute chronic inflammation is a contributor to the pathology of diverse degenerative diseases (Parkinson’s disease, Alzheimer’s disease and arthritis). Given the known limitations in Western medicine to treat a broad range of inflammatory related illness as well as the emergence of antibiotic resistance, there is a renewed interest in complementary and alternative medicines (CAMs) to achieve these means.

Methods

A high throughput (HTP) screening of >1400 commonly sold natural products (bulk herbs, cooking spices, teas, leaves, supplement components, nutraceutical food components, fruit and vegetables, rinds, seeds, polyphenolics etc.) was conducted to elucidate anti-inflammatory substances in lipopolysaccharide (LPS) (E. coli serotype O111:B4) monocytes: RAW 264.7 macrophages [peripheral], BV-2 microglia [brain]) relative to hydrocortisone, dexamethasone and L-N6-(1Iminoethyl)lysine (L-NIL). HTP evaluation was also carried out for lethal kill curves against E.coli 0157:H7 1x10⁶ CFU/mL relative to penicillin. Validation studies were performed to assess cytokine profiling using antibody arrays. Findings were corroborated by independent ELISAs and NO2–/iNOS expression quantified using the Griess Reagent and immunocytochemistry, respectively. For robust screening, we developed an in-vitro efficacy paradigm to ensure anti-inflammatory parameters were observed independent of cytotoxicity. This caution was taken given that many plants exert tumoricidal and anti-inflammatory effects at close range through similar signaling pathways, which could lead to false positives.

Results

The data show that activated BV-2 microglia cells (+ LPS 1μg/ml) release >10-fold greater IL-6, MIP1/2, RANTES and nitric oxide (NO2–), where RAW 264.7 macrophages (+ LPS 1μg/ml) produced > 10-fold rise in sTNFR2, MCP-1, IL-6, GCSF, RANTES and NO2–. Data validation studies establish hydrocortisone and dexamethasone as suppressing multiple pro-inflammatory processes, where L-NIL suppressed NO2–, but had no effect on iNOS expression or IL-6. The screening results demonstrate relative few valid hits with anti-inflammatory effects at < 250μg/ml for the following: Bay Leaf (Laurus nobilis), Elecampagne Root (Inula helenium), Tansy (Tanacetum vulgare),Yerba (Eriodictyon californicum) and Centipeda (Centipeda minima), Ashwagandha (Withania somnifera), Feverfew (Tanacetum parthenium), Rosemary (Rosmarinus officinalis), Turmeric Root (Curcuma Longa), Osha Root (Ligusticum porteri), Green Tea (Camellia sinensis) and constituents: cardamonin, apigenin, quercetin, biochanin A, eupatorin, (-)-epigallocatechin gallate (EGCG) and butein. Natural products lethal against [E. coli 0157:H7] where the LC₅₀ < 100 μg/ml included bioactive silver hydrosol-Argentyn 23, green tea (its constituents EGCG > Polyphenon 60 > (-)-Gallocatechin > Epicatechin > (+)-Catechin), Grapeseed Extract (Vitis vinifera), Chinese Gallnut (its constituents gallic acid > caffeic acid) and gallic acid containing plants such as Babul Chall Bark (Acacia Arabica), Arjun (Terminalia Arjuna) and Bayberry Root Bark (Morella Cerifera).

Conclusions

These findings emphasize and validate the previous work of others and identify the most effective CAM anti-inflammatory, antibacterial compounds using these models. Future work will be required to evaluate potential combination strategies for long-term use to prevent chronic inflammation and possibly lower the risk of sepsis in immunocompromised at risk populations.

Tanacetum polycephalum (L.) Schultz-Bip. induces mitochondrial-mediated apoptosis and inhibits migration and invasion in MCF7 cells

Tanacetumpolycephalum (L.) Schultz-Bip (Mokhaleseh) has been traditionally used in the treatment of headaches, migraines, hyperlipidemia and diabetes. The present study aimed to evaluate its anticancer properties and possible mechanism of action using MCF7 as an invitro model. T.polycephalum leaves were extracted using hexane, chloroform and methanol solvents and the cytotoxicity was evaluated using the MTT assay. Detection of the early apoptotic cells was investigated using acridine orange/propidium iodide staining. An Annexin-V-FITC assay was carried out to observe the phosphatidylserine externalization as a marker for apoptotic cells. High content screening was applied to analyze the cell membrane permeability, nuclear condensation, mitochondrial membrane potential (MMP) and cytochrome c release. Apoptosis was confirmed by using caspase-8, caspase-9 and DNA laddering assays. In addition, Bax/Bcl-2 expressions and cell cycle arrest also have been investigated. MTT assay revealed significant cytotoxicity of T.Polycephalum hexane extract (TPHE) on MCF7 cells with the IC₅₀ value of 6.42 ± 0.35 µg/mL. Significant increase in chromatin condensation was also observed via fluorescence analysis. Treatment of MCF7 cells with TPHE encouraged apoptosis through reduction of MMP by down-regulation of Bcl-2 and up-regulation of Bax, triggering the cytochrome c leakage from mitochondria to the cytosol. The treated MCF7 cells significantly arrested at G₁ phase. The chromatographic analysis elicited that the major active compound in this extract is 8β-hydroxy-4β,15-dihydrozaluzanin C. Taken together, the results presented in this study demonstrated that the hexane extract of T.Polycephalum inhibits the proliferation of MCF7 cells, resulting in the cell cycle arrest and apoptosis, which was explained to be through the mitochondrial pathway.

In-silico analyses of sesquiterpene-related compounds on selected Leishmania enzyme-based targets

A great number of sesquiterpenes are reported in the available literature as good antileishmanial leads. However, their mode of action at the molecular level has not been elucidated. The lack of molecular studies could be considered an impediment for studies seeking to improve sesquiterpene-based drug design. The present in silico study allows us to make important observations about the molecular details of the binding modes of a set of antileishmanial sesquiterpenes against four drug-enzyme targets [pteridine reductase-1 (PTR1), N-myristoyl transferase (NMT), cysteine synthase (CS), trypanothione synthetase (TryS)]. Through molecular docking it was found that two sesquiterpene coumarins are promising leads for the PTR1 and TryS inhibition purposes, and some xanthanolides also exhibited better affinity towards PTR1 and CS binding. In addition, the affinity values were clustered by Principal Component Analysis and drug-like properties were analyzed for the strongest-docking sesquiterpenes. The results are an excellent starting point for future studies of structural optimization of this kind of compounds.