Ligustolide A and B, two novel sesquiterpenes with rare skeletons and three 1,10-seco-guaianolide derivatives from Achillea ligustica

Phenolic Constituents, Photoprotective Effect, and Antioxidant Capacities of Achillea ligustica All

The present investigation was performed to figure out the chemical constituents and biological potential of polar extracts (AcOEt and BuOH) from Achillea ligustica, a medicinal species of the Asteraceae family. Liquid chromatography quadrupole time-of-flight mass spectrometry (LC-Q-TOF-MS) was utilized to conduct a preliminary analysis of the phytochemical profiles of the AcOEt and BuOH extracts. The analysis revealed the existence of twenty compounds in the AcOEt extract and twenty-two in the BuOH extract, classified into various types of secondary metabolites. Subsequently, the exudate from the plant yielded five flavonoids, including two 6-methoxyflavonols identified for the first time in this genus. The isolation of compounds from AcOEt and BuOH extracts was achieved through the combined use of column chromatography (silica gel and Sephadex LH-20) and preparative TLC chromatography. The structures have been elucidated using 1D and 2D NMR spectroscopy, alongside comparisons with research data. Our study measured the total phenolic and flavonoid contents and carried out a comprehensive range of antioxidant tests using DPPH, GOR, CUPRAC, reducing power, and O-phenanthroline assays. Both extracts exhibited considerable antioxidant potential and contained high levels of phenolic and flavonoid compounds. The photoprotective effect of the AcOEt and BuOH extracts was evaluated in vitro by measuring the sun protection factor. Both extracts exhibited a high capacity for UV radiation absorption. Consequently, this plant presents an intriguing prospect for future research focused on incorporating it into photoprotective cosmetic products and pharmaceutical formulations.

Discovery of sesquiterpene lactones with anti-inflammatory effect from Youngia japonica

The preliminary study revealed that the ethyl acetate eluate of Youngia japonica (YJ-E) could inhibit the expression of key proteins of p-p65, p-IκBα, p-IKKα/β, and p-AKT in LPS stimulated BV2 cell. Further phytochemical study led to the isolation of eight compounds from YJ-E, including one new sesquiterpene lactone. Their structures were elucidated by several spectroscopic data, and comparing the NMR data of known compound. In addition, all of the isolates were evaluated for the anti-inflammatory effect. As a result, compounds 3 and 4 distinctly attenuated the expressions of p-IκBα, p-p65, and p-AKT in LPS stimulated BV2 cell, respectively.

Diastereoselective allylation-based asymmetric total synthesis of 1,10-seco-guaianolides

A Cr(II)-mediated Nozaki-Hiyama allylation of aldehydes with functionalized chiral allylbromolactone paved the way to easily access β-hydroxy-aryl/alkyl-α-methylene-γ-butyrolactones in good yields with high diastereoselectivities. A subsequent undemanding translactonization was orchestrated in the efficient first asymmetric total synthesis of two 1,10-seco-guaianolides as a valuable extension of the strategy developed.

Highly oxygenated guaiane-type sesquiterpene lactones from Artemisia sacrorum and their antihepatoma activity

The ethanol and EtOAc extracts of Artemisia sacrorum exhibited inhibitory effect against HepG2, Huh7, and SK-Hep-1 cell lines with inhibitory ratios of 65.5%, 28.1%, 84.6%, and 93.5%, 82.0%, 89.0% at 200 μg/mL. Twenty-three undescribed guaiane-type sesquiterpene lactones, artemisacrolides A‒W, were isolated from A. sacrorum under the guidance of antihepatoma activity. Their structures were elucidated by spectral data (HRESIMS, IR, UV, 1D and 2D NMR), ECD calculations, and a single-crystal X-ray diffraction. Artemisacrolides A‒U were guaiane-type sesquiterpene lactones possessing α-methylene-γ-lactone and containing acetoxyl groups at C-8, and artemisacrolides V and W represented the first report from the genus Artemisia with a 1,10-rearranged guaiane-type sesquiterpene lactone. Antihepatoma assay suggested that artemisacrolides A‒U demonstrated better inhibitory activity in Huh7 and SK-Hep-1 cells than those of HepG2 cells. Among them, nine compounds exhibited significant inhibitory activity against Huh7 cells with IC50 values of 8.2-14.3 μM, superior or equal to that of sorafenib; seven compounds demonstrated obvious activity against SK-Hep-1 cells with IC50 values of 13.5-19.2 μM, which were equivalent to that of sorafenib. Artemisacrolides B and E were the most active ones in three human hepatoma cell lines with IC50 values of 21.9, 8.2, 16.9 and 22.6, 9.0, 17.3 μM.

Artemdubinoids A-N: novel sesquiterpenoids with antihepatoma cytotoxicity from Artemisia dubia

In pursuit of effective agents for hepatocellular carcinoma derived from the Artemisia species, this study built upon initial findings that an ethanol (EtOH) extract and ethyl acetate (EtOAc) fraction of the aerial parts of Artemisia dubia Wall. ex Bess. exhibited cytotoxicity against HepG2 cells with inhibitory rates of 57.1% and 84.2% (100 μg·mL-1), respectively. Guided by bioactivity, fourteen previously unidentified sesquiterpenes, artemdubinoids A-N (1-14), were isolated from the EtOAc fraction. Their structural elucidation was achieved through comprehensive spectroscopic analyses and corroborated by the comparison between the experimental and calculated ECD spectra. Single crystal X-ray diffraction provided definitive structure confirmation for artemdubinoids A, D, F, and H. Artemdubinoids A and B (1-2) represented unique sesquiterpenes featuring a 6/5-fused bicyclic carbon scaffold, and their putative biosynthetic pathways were discussed; artemdubinoid C (3) was a novel guaianolide derivative that might be formed by the [4 + 2] Diels-Alder reaction; artemdubinoids D and E (4-5) were rare 1,10-seco-guaianolides; artemdubinoids F-K (6-11) were chlorine-containing guaianolides. Eleven compounds exhibited cytotoxicity against three human hepatoma cell lines (HepG2, Huh7, and SK-Hep-1) with half-maximal inhibitory concentration (IC50) values spanning 7.5-82.5 μmol·L-1. Artemdubinoid M (13) exhibited the most active cytotoxicity with IC50 values of 14.5, 7.5 and 8.9 μmol·L-1 against the HepG2, Huh7, and SK-Hep-1 cell lines, respectively, which were equivalent to the positive control, sorafenib.

Isolation of Secondary Metabolites from Achillea grandifolia Friv. (Asteraceae) and Main Compounds' Effects on a Glioblastoma Cellular Model

This study aims at the isolation and structural determination of the secondary metabolites of the herbaceous perennial plant Achillea grandifolia Friv. (Asteraceae). The examination of the non-volatile content of the leaves and flowers of A. grandifolia afforded the isolation of sixteen secondary metabolites. On the basis of NMR spectra, the identified compounds included ten sesquiterpene lactones; three guaianolides-rupicolin A (1), rupicolin B (2), and (4S,6aS,9R,9aS,9bS)-4,6a,9-trihydroxy-9-methyl-3,6-dimethylene-3a,4,5,6,6a,9,9a,9b-octahydro-3H-azuleno [4,5-b]furan-2-one (3); two eudesmanolides-artecalin (4) and ridentin B (5); two sesquiterpene methyl esters-(1S,2S,4αR,5R,8R,8αS)-decahydro-1,5,8-trihydroxy-4α,8-dimethyl-methylene-2-naphthaleneacetic acid methylester (6) and 1β, 3β, 6α-trihydroxycostic acid methyl ester (7); three secoguaianolides-acrifolide (8), arteludovicinolide A (9), and lingustolide A (10); and an iridoid-loliolide (11). Moreover, five known flavonoids, i.e., apigenin, luteolin, eupatolitin, apigenin 7-O-glucoside, and luteolin 7-O-glucoside (12-16) were also purified from the aerial parts of the plant material. We also investigated the effect of rupicolin A (1) and B (2) (main compounds) on U87MG and T98G glioblastoma cell lines. An MTT assay was performed to define cytotoxic effects and to calculate the IC50, while flow cytometry was employed to analyze the cell cycle. The IC50 values of reduced viability during the 48 h treatment for compound (1) and (2) were 38 μM and 64 μM for the U87MG cells and 15 μM and 26 μM for the T98G cells, respectively. Both rupicolin A and B induced a G2/M cell cycle arrest.

Chlorine-containing guaianolide sesquiterpenoids from Achillea millefolium L. with inhibitory effects against LPS-induced NO release in BV-2 microglial cells

Chlorine-containing guaianolide sesquiterpenoids are rare natural compounds that are mainly derived from plants of the Asteraceae family. Our previous investigations on the whole plant of Achillea millefolium L. resulted in the discovery of two chlorine-containing guaianolide sesquiterpenoids. In the present study, a LC‒MS tracking strategy based on the characteristic isotropic peak of atomic chlorine was employed to isolate nine undescribed chlorine-containing guaianolide sesquiterpenoids, Millefolactons B1-B9, from A. millefolium L.. The structures of these compounds were elucidated by spectroscopic data analysis, and the corresponding absolute configurations were determined by single-crystal X-ray crystallography and ECD data analysis. Millefolactons B2-B7 displayed inhibitory activities against LPS-induced NO release in BV-2 microglial cells.

A Dimerosesquiterpene and Sesquiterpene Lactones from Artemisia argyi Inhibiting Oncogenic PI3K/AKT Signaling in Melanoma Cells

A library of more than 2500 plant extracts was screened for activity on oncogenic signaling in melanoma cells. The ethyl acetate extract from the aerial parts of Artemisia argyi displayed pronounced inhibition of the PI3K/AKT pathway. Active compounds were tracked with the aid of HPLC-based activity profiling, and altogether 21 active compounds were isolated, including one novel dimerosequiterpenoid (1), one new disesquiterpenoid (2), three new guaianolides (3-5), 12 known sesquiterpenoids (6-17), and four known flavonoids (19-22). A new eudesmanolide derivative (13b) was isolated as an artifact formed by methanolysis. Compound 1 is the first adduct comprising a sesquiterpene lactone and a methyl jasmonate moiety. The absolute configurations of compounds 1 and 3-18 were established by comparison of their experimental and calculated ECD spectra. The absolute configuration for 2 was determined by X-ray diffraction analysis. Guaianolide 8 was the most potent sesquiterpene lactone, inhibiting the PI3K/AKT pathway with an IC₅₀ value of 8.9 ± 0.9 μM.

Chemical Constituents from the Aerial Parts of Artemisia iwayomogi and Their Anti-Neuroinflammatory Activities

Neuroinflammation, predominantly mediated by microglial activation, is a key immunological response in the pathogenesis of neurodegenerative disorders. In our preliminary study, the aerial part of Artemisia iwayomogi inhibits LPS-induced microglial activation. The present study aims to identify chemical constituents with anti-neuroinflammatory properties in the aerial parts of A. iwayomogi. Two new guaianolide sesquiterpenes, iwayomogins A and B (1 and 2), along with thirteen known sesquiterpene lactones (3–15), one diterpene glycoside (16), and nine phenolic compounds (17–25) were isolated from the aerial parts of A. iwayomogi by repeated chromatography. The structures of the isolates were elucidated by their spectroscopic data. All isolates were evaluated for their inhibitory activities on nitric oxide (NO) production in LPS-induced BV-2 microglial cells. 2,3-Dehydro-1-epi-asperilin (11) exhibited the strongest inhibitory effect on NO production (IC50 value of 1.78 μM). In the molecular docking study, three compounds (1, 2, and 11) showed good binding affinities with iNOS. Additionally, compounds 1, 2, and 11 inhibit pro-inflammatory cytokines (TNF-α and IL-6) in dose-dependent manners. The present study demonstrates that the chemical constituents from A. iwayomogi inhibit NO production and pro-inflammatory cytokine release in BV-2 cells. However, further evaluation with biological experiments utilizing in vivo models is necessary.

Essential Oil Biodiversity of Achillea ligustica All. Obtained from Mainland and Island Populations

Background: The genus Achillea is rich in essential oil (EO) with high chemical diversity. In this study, eight EO samples obtained from flowers and leaves of Achillea ligustica All. collected on the Mediterranean mainland and island locations were analyzed to evaluate their possible chemical diversity. Methods: Sixteen samples of EO were analyzed by GC-MS, leading to the identification of 95 compounds in the leaves and 86 compounds in the flowers; a statistical analysis was performed to determine the chemical polymorphism. Results: Monoterpenes, such as β-pinene, borneol, ɑ-terpineol and isobornyl acetate, were more abundant in the continental samples, while the insular samples were richer in 1,8-cineole. Fragranyl acetate and fragranol were detected in remarkable concentrations in sample 8. The fruits of sample 8 were then cultivated under controlled agronomic conditions, providing plants rich in these compounds (sample 9). The geographical variability influenced the EO compositions, with unique observed chemotypes and a high degree of diversity among samples collected in various areas (mainland or island). Statistical analyses did not reveal any pattern between the geographical provenience and the compositions. Conclusion: Samples were distributed based on the plant organ, confirming the already reported high degree of chemical polymorphism of this species. Sample 8 could be used as a source of fragranol and fragranyl acetate, with potential applications in the insecticidal and pheromone industries.

Total Syntheses of Paraconic Acids and 1,10-seco-Guaianolides via a Barbier Allylation/Translactonization Cascade of 3-(Bromomethyl)-2(5H)-furanone

A palladium-catalyzed Barbier allylation/translactonization cascade reaction was established for the rapid construction of β,γ-disubstituted α-exo-methylene-γ-butyrolactone, an important motif in sesquiterpenes. Dimethyl zinc played significant roles in both steps for the umpolung of π-allylpalladium as a nucleophile and promoting a Lewis acid-mediated translactonization. This sequence showed a broad substrate scope and was further harnessed for the synthesis of two paraconic acids as well as the first protecting-group-free total synthesis of two 1,10-seco-guaianolides.

Cytotoxicity and Anti-cancer Activity of the Genus Achillea L

BACKGROUND

The genus Achillea L. is rich in bioactive sesquiterpenes and flavonoids; most of the studied species exhibit several biological activities and are used as emmenagogue, wound healing and analgesic agents. Some species are also used in local folklore medicine.

OBJECTIVE

Following a literature survey, we discuss the anti-cancer properties of Achillea species, taking into consideration ethnopharmacological data on their use in traditional medicine for the treatment of cancer. In addition, we screened extracts and isolated secondary metabolites from A. coarctata for cytotoxicity, upon information based on local traditional medicine. The plant was collected in Kozani (Northern Greece), where it is locally used for treating gastrointestinal disorders, including stomach cancer.

METHODS

A selection of the relevant data was performed through a search in PubMed, Scopus, Google Scholar and Science Direct databases. In addition, extracts and isolated compounds from A. coarctata were tested for their in vitro activity against the human cancer cell lines MCF-7 and HeLa.

CONCLUSION

The genus Achillea L. is a valuable source of bioactive secondary metabolites. The most significant outcome of the investigation of medicinal plants is the documentation and the assessment of the traditional information and its use and perspectives in the light of modern pharmacology.

Sesquiterpenes from Myrrh and Their ICAM-1 Inhibitory Activity In Vitro

By using various chromatographic steps (silica flash, CPC, preparative HPLC), 16 sesquiterpenes could be isolated from an ethanolic extract of myrrh resin. Their chemical structures were elucidated by 1D and 2D NMR spectroscopy and HRESIMS. Among them, six previously unknown compounds (1-6) and another four metabolites previously not described for the genus Commiphora (7, 10, 12, 13) could be identified. Sesquiterpenes 1 and 2 are novel 9,10-seco-eudesmanes and exhibited an unprecedented sesquiterpene carbon skeleton, which is described here for the first time. New compound 3 is an 9,10 seco-guaian and the only peroxide isolated from myrrh so far. Compounds 1, 2, 4, 7-9, 11, 13-16 were tested in an ICAM-1 in vitro assay. Compound 7, as well as the reference compound furanoeudesma-1,3-diene, acted as moderate inhibitors of this adhesion molecule ICAM-1 (IC50: 44.8 and 46.3 μM, respectively). These results give new hints on the activity of sesquiterpenes with regard to ICAM-1 inhibition and possible modes of action of myrrh in anti-inflammatory processes.

Artemlavanins A and B from Artemisia lavandulaefolia and Their Cytotoxicity Against Hepatic Stellate Cell Line LX2

Two new sesquiterpenoids, artemlavanins A (1) and B (3), together with fifteen known compounds (2 and 4-17) were isolated from the EtOH extract of Artemisia lavandulaefolia. The structures of new compounds were elucidated by extensive spectroscopic analyses (HRESIMS, 1D and 2D NMR) and ECD calculations. Compound 1 was a sesquiterpenoid lactone possessing a rearranged eudesmane skeleton; compounds 2-5, 6-8, 9 and 10-12 belonged to the eudesmane, guaiane, oppositane and farnesane sesquiterpenoids, respectively; compounds 13-17 were the phenyl derivatives with a 4-hydroxyacetophenone moiety. Twelve compounds (1-3, 5-7, 10-12, 14, 15 and 17) displayed cytotoxicity against hepatic stellate cell line LX2 (HSC-LX2) with IC50 values ranging from 35.1 to 370.3 μM. Compounds 2, 7, 10-12 and 17 exhibited the stronger cytotoxicity than silybin (IC50, 169.6 μM) with IC50 values of 82.1, 35.1, 95.0, 83.8, 81.6 and 90.1 μM. Compound 7 as the most active one showed significant inhibition on the deposition of human collagen type I (Col I), human hyaluronic acid (HA) and human laminin (HL) with IC50 values of 10.7, 24.5 and 13.3 μM.

Anti-Apoptotic and Antioxidant Effects of 3-Epi-Iso-Seco-Tanapartholide Isolated from Artemisia Argyi Against Iodixanol-Induced Kidney Epithelial Cell Death

Iodixanol is a non-ionic iso-osmolar contrast agent, but it is a risk factor for kidney damage and increases morbidity and mortality. In this study, we investigated the effect of 9 sesquiterpenes isolated from mugwort (Artemisia argyi) in contrast agent-induced cytotoxicity in LLC-PK1 cells. Cells were exposed to nine sesquiterpene compounds for 2 h, followed by incubation with iodixanol for 3 h. Cell viability was assessed using the Ez-Cytox assay. The level of reactive oxygen species was measured using 2′,7′-dichlorodihydrofluorescein diacetate staining. Apoptotic cell death was detected using annexin V/PI staining. In addition, immunofluorescence staining and western blotting were performed using antibodies against proteins related to apoptosis, oxidative stress, and MAPK pathways. The most effective 3-epi-iso-seco-tanapartholide (compound 8) among the 9 sesquiterpene compounds protected LLC-PK1 cells from iodixanol-induced cytotoxicity, oxidative stress, and apoptotic cell death. Pretreatment with compound 8 reversed iodixanol-induced increases in the expression of JNK, ERK, p38, Bax, caspase-3, and caspase-9. It also reversed the iodixanol-induced decrease in Bcl-2 expression. Furthermore, pretreatment with compound 8 caused nuclear translocation of Nrf2 and upregulated HO-1 via the Nrf2 pathway in iodixanol-treated LLC-PK1 cells. Thus, we demonstrated here that compound 8 isolated from A. argyi has the potential to effectively prevent iodixanol-induced kidney epithelial cell death via the caspase-3/MAPK pathways and HO-1 via the Nrf2 pathway.

Preparation and Phytotoxicity Evaluation of 11,13-Dehydro seco-Guaianolides

11,13-Dehydro seco-guaianolides, a particular type of sesquiterpene lactones, were synthesized from the commercially available α-santonin (11) using a facile strategy involving a high-yielding photochemical reaction. Natural products 10 and 17 from Artemisia gorgonum were synthesized in good yields. Specifically, compound 10 was obtained in five steps with an overall yield of 17%. The sesquiterpene lactones were tested in the etiolated wheat coleoptile bioassay, and the most active compounds were assayed on standard target species. Guaianolide 13 showed the highest phytotoxic activities when compared with the known herbicide Logran.

1,10-Secoguaianolides from Artemisia austro-yunnanensis and Their Anti-Inflammatory Effects

Seven 1,10-secoguaianolides 1⁻7, including a new one (compound 1), were isolated from Artemisia austro-yunnanensis and identified by HRESIMS and other spectroscopic methods. Their anti-inflammatory effects were evaluated by the model of LPS-induced RAW264.7 cells in vitro. Bioassay results showed that six of them (1⁻4, 6 and 7), with the exception of 5, produce some cytotoxicity on RAW264.7 cells at its high dosage, can significantly decrease the release of NO, TNF-α, IL-1β, IL-6 and PGE2 in a dose dependent manner, and down-regulate the expression of proteins iNOS and COX-2. The mechanism study indicated they regulated the NF-κB dependent transcriptional activity through decreasing the phosphorylation of NF-κB. Further, the relationship between their structures and cytokines to anti-inflammatory were studied by PCA and discussed.

Sesquiterpene Lactones and Phenolics from Roots of Leontodon hispidus subsp. hispidus

The phytochemical investigation on roots of Leontodon hispidus L. subsp. hispidus, led to the isolation of nine sesquiterpene lactones including two eudesmanolides of santamarine type and three lactucin-like guaianolides together with four known phenolic compounds. The eudesmanolides – santamarine and 11 β,13-dihydrosantamarine, guaianolides – matricarin, deacetylmatricarin and deacetylmatricarin 8- O- β-glucopyranoside, and phenolics – syringaldehyde, 3-hydroxy-1-(4-hydroxy-3-methoxyphenyl)-1-propanone, syringin and dihydroconiferin were found for the first time in Leontodon.

Sesquiterpenoids with Various Carbocyclic Skeletons from the Flowers of Chrysanthemum indicum

A phytochemical investigation of the flowers of Chrysanthemum indicum yielded sesquiterpenoids 1-25 with various carbocyclic skeletons, including 10 new (1-10) and 15 known (11-25) analogues. The structures were elucidated via their physical data, while the absolute configuration of compounds 6, 8, and 10 was assessed via electronic circular dichroism analysis. The evaluation of the effect of sesquiterpenoids on porcine epidemic diarrhea virus (PEDV) replication showed that compounds 1-5, 12, 14, 16, 17, 19, and 21 increased cell viability against cell death in PEDV-injected cells. Compounds 2, 12, and 17 were selected and investigated for their inhibition of proteins required for PEDV replication. Compounds 2 and 17 significantly reduced PEDV nucleocapsid and spike protein synthesis compared with azauridin as a positive control.

Identification of bitter components from Artemisia princeps Pamp

Identification of bitter components from the aerial parts of Artemisia princeps Pamp. was performed to search for a method to eliminate the bitter taste from A. princeps products. The aerial parts of A. princeps were extracted in an aqueous EtOH solution, and the obtained extracts were partitioned into essential-oil, flavonoid-rich, n-BuOH, and aqueous fractions. Two purified bitter sesquiterpenoids were identified through repeated column chromatography of the bitterest fraction, the flavonoid-rich fraction, through an activity-guided fractionation method. The compounds were identified to be 1α,6α,8α-trihydroxy-5α,7βH-guaia-3,9,11(13)-trien-12-oic acid and artecalin, respectively, based on the interpretation of NMR, MS, and IR spectroscopic data. Both compounds were 50 times bitterer than caffeine and had similar bitterness to quinine HCl. Neither eupatilin nor jaceosidin, the major active components of A. princeps, showed any bitterness.

Phytochemical analysis of Achillea ligustica All. from Lipari Island (Aeolian Islands)

A complete chemical investigation of Achillea ligustica All. growing at Lipari (Aeolian Island, Sicily) has been carried out. Seventeen metabolites have been isolated and characterised from dichloromethane and methanol extracts of flowers and aerial parts, and GC/MS analyses of petroleum ether extracts was carried out, revealing a composition in sesquiterpenoids similar to those reported for populations from Greece, Sicily and Algeria, showing the presence of (3RS,6RS)-2,6-dimethyl-1,7-octadiene-3,6-diol (1), 2,6-dimethyl-octa-3(E),7-diene-2,6-diol (2), iso-seco-tanapartholide (3) from DCM fraction. In addition from the methanolic extract of the aerial parts, peculiar flavonoid glucuronides have been isolated: i.e. apigenin-7-O-glucuronide (12) and quercetin 3-O-glucuronide (14). These metabolites have been reported in this species for the first time. The isolated flavonoids were previously recognised in several species of this complex genus and for this reason seems to be highly retained secondary metabolites of importance from the chemotaxonomic point of view.

Terpenes and polyacetylenes from cultivated Artemisia granatensis boiss (Royal chamomile) and their defensive properties

Artemisia granatensis, an endemic endangered plant species from Sierra Nevada (Spain) has been successfully cultivated in artificial systems (plants in artificial soil and transformed in vitro roots) to generate enough plant biomass (aerial and root) to allow for its chemical and biological study and at the same time to provide with methods for the sustainable production of the plant and its metabolites. A eudesmanolide (17) along with six sesquiterpenes (11-16), nine monoterpenes (2-10), one nor-monoterpene (1), three acetylenic spiroacetal enoleters (18-20) and one coumarin (21) have been identified from the aerial plant ethanolic extract. Acetylenic spiroacetal enoleters 18-19 and coumarins 21-23 have been isolated from the transformed root ethanolic extract. These extracts and some isolated compounds or mixtures of them have been tested for their insect antifeedant effects against Spodoptera littoralis, Myzus persicae and Rhopalosiphum padi. Significant antifeedant properties were determined for the aerial plant extract, spiroacetals 19-20 and secoguaianolides 13+14 and 16.

Anti-inflammatory Activity of New Guaiane Acid Derivatives from Achillea Coarctata

Chromatographic investigation of the methylene chloride/methanol extract of aerial parts of Achillea coarctata afforded two new guaiane acid derivatives, 1α,6α,8α-trihydroxy-5α,7βH-guaia-3,10(14),11(13)-trien-12-oic acid (1) and 1α,6α,8α-trihydroxy-5α,7βH-guaia-3,9,11(13)-trien-12-oic acid (2), in addition to three known compounds, ligustolide-A (3), arteludovicinolide-A (4) and austricin (5). Structures were elucidated by spectroscopic analyses including: 1H and 13C NMR, COSY, HMQC, HMBC and NOESY NMR spectroscopy, as well as MS analysis. Proliferation of beneficial macrophages was significantly enhanced by treatment with 1 and 2. Additionally, treatment with compounds 2 and 4 led to a potentially significant inhibition in nitric oxide generation from raw murine macrophage 264.7, which was stimulated by bacterial lipopolysaccharide. Compounds 2 and 4 exhibited anti-inflammatory properties, based on a nitric oxide assay.

Chemotypes in Achillea collina based on sesquiterpene lactone profile

The lactone profile of six origins of Achillea collina growing in Bulgaria was studied and significant variability was observed. The reasons for the differences in the lactone composition are discussed. Twenty-five components in total were isolated and identified, while the presence of ten lactones was proved by intensive TLC analysis in comparison with reference compounds. The structures of the components 17, 20, 25-30 were established by spectroscopic methods. The structure of 7, a cyclization product of 6, was also discussed. The anti-inflammatory activity of some extracts, fractions and individual compounds was tested in vitro by determining the inhibitory effects on induced human neutrophils.

Cytotoxic constituents of Achillea clavennae from Montenegro

Examination of the aerial parts of Achillea clavennae afforded eight guaianolides (1-8), three bisabolenes (9-11), four flavonols (12-15), sesamin (lignan) and isofraxidin (coumarin). The structures of the new compounds (2, 4, 5, 7 and 10) were determined by spectroscopic methods. The antiproliferative action of 2, 8, 9 and 12 were tested to HeLa, K562 and Fem-X human cancer cell lines. Guaianolides 2 (9alpha-acetoxyartecanin) and 8 (apressin) showed significant cytotoxic effects to all tested lines and inducumenone (9) exhibited a moderate activity. The most active was flavonol centaureidin (12), already known as cytotoxic compound.

Comparative radical scavenging and antidiabetic activities of methanolic extract and fractions from Achillea ligustica ALL

The yield of methanolic extract and total phenol and non polar content of flowered parts from Achillea ligustica ALL. are reported. GC-MS analysis of the non polar fraction showed that the triterpene moretenol was the major constituent (17.228%) followed by stigmast-6-en-3beta-ol, veridiflorol and beta-amyrin (7.524%, 5.078% 4.470%, respectively). The antioxidant activities of the methanolic extract and its fractions from A. ligustica were carried out using two different in vitro assays, 2,2-diphenyl-1-picrylhydrazyl (DPPH) test and lipid peroxidation of liposomes assay. Methanolic extract showed higher radical scavenging activity on DPPH (IC50 of 50 microg/ml). This activity is probably due to the phenolic fraction which shown an IC50 value of 22 microg/ml. A different result was obtained from the methanolic extract on the lipid peroxidation of liposomes (IC50 of 416 microg/ml). The alpha-amylase inhibition assay was applied to evaluate antidiabetic activity. The methanolic extract showed weak activity (28.18% at 1 mg/ml) while the n-hexane fraction showed 74.96% inhibition at 250 microg/ml.

Vinyl Sulfoxides as Stereochemical Controllers in Intermolecular Pauson-Khand Reactions: Applications to the Enantioselective Synthesis of Natural Cyclopentanoids

The use of sulfoxides as chiral auxiliaries in asymmetric intermolecular Pauson-Khand reactions is described. After screening a wide variety of substituents on the sulfur atom in alpha,beta-unsaturated sulfoxides, the readily available o-(N,N-dimethylamino)phenyl vinyl sulfoxide (1 i) has proved to be highly reactive with substituted terminal alkynes under N-oxide-promoted conditions (CH3CN, 0 degrees C). In addition, these Pauson-Khand reactions occurred with complete regioselectivity and very high diastereoselectivity (de=86->96 %, (S,R(S)) diastereomer). Experimental studies suggest that the high reactivity exhibited by the vinyl sulfoxide 1 i relies on the ability of the amine group to act as a soft ligand on the alkyne dicobalt complex prior to the generation of the cobaltacycle intermediate. On the other hand, both theoretical and experimental studies show that the high stereoselectivity of the process is due to the easy thermodynamic epimerization at the C5 center in the resulting 5-sulfinyl-2-cyclopentenone adducts. When it is taken into account that the known asymmetric intermolecular Pauson-Khand reactions are limited to the use of highly reactive bicyclic alkenes, mainly norbornene and norbornadiene, this novel procedure constitutes the first asymmetric version with unstrained acyclic alkenes. As a demonstration of the synthetic interest of this sulfoxide-based methodology in the enantioselective preparation of stereochemically complex cyclopentanoids, we have developed very short and efficient syntheses of the antibiotic (-)-pentenomycin I and the (-)-aminocyclopentitol moiety of a hopane triterpenoid.