Search

Several sesquiterpene lactones (STLs) have been tested as lead drugs in cancer clinical trials. Salograviolide-A (Sal-A) and salograviolide-B (Sal-B) are two STLs that have been isolated from Centaurea ainetensis, an indigenous medicinal plant of the Middle Eastern region. The parent compounds Sal-A and Sal-B were modified and successfully prepared into eight novel guaianolide-type STLs (compounds 1–8) bearing ester groups of different geometries. Sal-A, Sal-B, and compounds 1–8 were tested against a human colorectal cancer cell line model with differing p53 status, HCT116 with wild-type p53 and HCT116 p53−/− null for p53, and the normal-like human colon mucosa cells with wild-type p53, NCM460. IC50 values indicated that derivatization of Sal-A and Sal-B resulted in potentiation of HCT116 cell growth inhibition by 97% and 66%, respectively. The effects of the different molecules on cancer cell growth were independent of p53 status. Interestingly, the derivatization of Sal-A and Sal-B molecules enhanced their anti-growth properties versus 5-Fluorouracil (5-FU), which is the drug of choice in colorectal cancer. Structure-activity analysis revealed that the enhanced molecule potencies were mainly attributed to the position and number of the hydroxy groups, the lipophilicity, and the superiority of ester groups over hydroxy substituents in terms of their branching and chain lengths. The favorable cytotoxicity and selectivity of the potent molecules, to cancer cells versus their normal counterparts, pointed them out as promising leads for anti-cancer drug design.

Inflammation is a crucial and complex process that reestablishes the physiological state after a noxious stimulus. In pathological conditions the inflammatory state may persist, leading to chronic inflammation and causing tissue damage. Sesquiterpene lactones (SLs) are composed of a large and diverse group of highly bioactive plant secondary metabolites, characterized by a 15-carbon backbone structure. In recent years, the interest in SLs has risen due to their vast array of biological activities beneficial for human health. The anti-inflammatory potential of these compounds results from their ability to target and inhibit various key pro-inflammatory molecules enrolled in diverse inflammatory pathways, and prevent or reduce the inflammatory damage on tissues. Research on the anti-inflammatory mechanisms of SLs has thrived over the last years, and numerous compounds from diverse plants have been studied, using in silico, in vitro, and in vivo assays. Besides their anti-inflammatory potential, their cytotoxicity, structure–activity relationships, and pharmacokinetics have been investigated. This review aims to gather the most relevant results and insights concerning the anti-inflammatory potential of SL-rich extracts and pure SLs, focusing on their effects in different inflammatory pathways and on different molecular players.

Cotula cinerea, belonging to the tribe Anthemideae, is a plant widespread in the Southern hemisphere. It is frequently used in folk medicine in North African countries for several of its medical properties, shown by its extracts and essential oils. The dichloromethane extract obtained from its aerial parts demonstrated antibiotic activity against Enterococcus faecalis and was fractionated by bioguided purification procedures affording five main sesquiterpene lactones. They were identified by spectroscopic methods (NMR and ESIMS data) as guaiantrienolides, i.e., 6-acetoxy-1β-,6-acetoxy-1α-, and 6-acetoxy-10-β-hydroxyguaiantrienolide (1–3), and germacrenolides, i.e., haagenolide and 1,10-epoxyhaagenolide (4 and 5). The absolute configuration was assigned by applying the advanced Mosher’s method to haagenolide and by X-ray diffraction analysis to 1,10-epoxyhaagenolide. The specific antibiotic and antibiofilm activities were tested toward the clinical isolates of Enterococcus faecalis. The results showed that compounds 3–5 have antibacterial activity against all the strains of E. faecalis, while compound 2 exhibited activity only toward some strains. Compound 1 did not show this activity but had only antibiofilm properties. Thus, these metabolites have potential as new antibiotics and antibiofilm against drug resistant opportunistic pathogens.

Chicory (Cichorium intybus L.) is a medicinal and industrial plant from the Asteraceae family that produces a variety of sesquiterpene lactones (STLs), most importantly bitter guaianolides: lactucin, lactucopicrin and 8-deoxylactucin as well as their modified forms such as oxalates. These compounds have medicinal properties; however, they also hamper the extraction of inulin – a very important food industry product from chicory roots. The first step in guaianolide biosynthesis is catalyzed by germacrene A synthase (GAS) which in chicory exists in two isoforms – GAS long (encoded by CiGASlo) and GAS short (encoded by CiGASsh). AmiRNA silencing was used to obtain plants with reduced GAS gene expression and level of downstream metabolites, guaianolide-15-oxalates, as the major STLs in chicory. This approach could be beneficial for engineering new chicory varieties with varying STL content, and especially varieties with reduced bitter compounds more suitable for inulin production.

Agriculture is the largest user of world water resources, accounting for 70% of all consumption. Reducing water consumption and increasing water use efficiency in agriculture are two of the main challenges that need to be faced in the coming decades. Radicchio Rosso di Treviso Tardivo (RTT) is a vegetable that requires a water forcing process prior to final commercialization which presents a significant environmental impact due to the high water volumes used and then dispersed into the environment. The experiment was aimed at reducing the water use in the forcing process of RTT, by developing a pilot system with recycled water in a closed loop through ozone treatment. Concerning water quality, the redox potential value was higher in the ozonized system, whereas turbidity, pH and electrical conductivity of the ozonized system did not change significantly from the control. Yield and quality of plants obtained in the ozonized system did not significantly differ from the control plants except for the antioxidant activity that was higher in plants forced using the water treated with ozone. Our initial results suggest that the ozone treatment could be applied in the forcing process and is suitable for growers, saving up to 95% of water volumes normally used for this cultivation practice.

Analysis of composition of sesquiterpene lactone fraction of leaf cuticular neutral lipids of Amphoricarpos complex from two different localities in north Montenegro, i.e., canyon of river Tara (A. autariatus ssp. autariatus) and mountain Zeletin (A. autariatus ssp. bertisceus) afforded sesquiterpene lactones with guaianolide skeletons (17 compounds), so called amphoricarpolides, typical for this genus. Nine of them, 9-17, were new compounds, and their structures were elucidated by detailed analyses of IR, NMR, and MS data.

Thapsia laciniata Rouy (Apiaceae) produces irregular and regular sesquiterpenoids with thapsane and guaiene carbon skeletons, as found in other Apiaceae species. A transcriptomic analysis utilizing Illumina next-generation sequencing enabled the identification of novel genes involved in the biosynthesis of terpenoids in Thapsia. From 66.78 million HQ paired-end reads obtained from T. laciniata roots, 64.58 million were assembled into 76,565 contigs (N50: 1261 bp). Seventeen contigs were annotated as terpene synthases and five of these were predicted to be sesquiterpene synthases. Of the 67 contigs annotated as cytochromes P450, 18 of these are part of the CYP71 clade that primarily performs hydroxylations of specialized metabolites. Three contigs annotated as aldehyde dehydrogenases grouped phylogenetically with the characterized ALDH1 from Artemisia annua and three contigs annotated as alcohol dehydrogenases grouped with the recently described ADH1 from A. annua. ALDH1 and ADH1 were characterized as part of the artemisinin biosynthesis. We have produced a comprehensive EST dataset for T. laciniata roots, which contains a large sample of the T. laciniata transcriptome. These transcriptome data provide the foundation for future research into the molecular basis for terpenoid biosynthesis in Thapsia and on the evolution of terpenoids in Apiaceae.

Chloroform extracts of the underground parts of two Balkan endemic Laserpitium species, Laserpitium zernyi Hayek and Laserpitium ochridanum Micevski, were chemically investigated. Five unknown guaianolides from the class of slovanolides, of which four were additionally 2 beta-esterified, as well as two lactones, previously identified in other Laserpitium species, were isolated from the L. ochridanum extract. From the L. zernyi extract one slovanolide derivative was isolated for the first time in the genus Laserpitium. In addition, the phenylpropanoid latifolone and six known sesquiterpene lactones, characterised as derivatives of slovanolide and silerolide, were isolated from the extracts of both species. The cytotoxic activities of the total extracts and the isolated compounds were tested using MTT and SRB assays on the two human breast cancer cell lines, MCF 7/6 and MCF 7/AZ. The extracts exerted cytotoxic activities with the IC50 values ranging 65.21-348.25 mu g/mL. The L ochridanum extract was most potent in the MTT test with IC50 values of 65.21 and 66.09 mu g/mL in the MCF 7/AZ and MCF 7/6 cell lines, respectively. The highest cytotoxic activity exerted 2 beta,8 alpha-di-angeloyloxy-10 beta-hydroxy-6 alpha H-guaian-3,(7-11)-dien-12,6-olide, a slovanolide derivative with an additional double bond in lactone ring, on highly invasive MCF 7/6 cell line, with IC50 value 0.7 mu M in both assays tested. Generally, guaianolides with a higher number of ester moieties at the positions 2 beta, 8 alpha, 10 beta or 11 alpha exhibited IC50 values in the micromolar range, while eudesmanolides and guaianolides with a lower number of esters did not induce significant cytotoxicity.

The aerial parts of Picris pauciflora Willd. (Asteraceae) yielded 11β, 13-dihydrolactucin, while the roots of the plant afforded 3-β-D-glucopyranosides of 11β, 13-dihydrozaluzanin C and 9α-hydroxy-11β, 13-dihydrozaluzanin C (ixerin F). The guaianolides were isolated from ethanol extracts using chromatographic methods and were identified on the basis of spectral analysis. They are reported for the first time from this species.

Conformational analysis of 9alpha-acetoxycumambrine A 1 and 8-O-isobutiryl-9alpha-acetoxycumambrine B 2 was carried out by low-temperature NMR studies. Results suggested that lactones 1 and 2 are mixtures of two distinctive conformers, I and II. Based on low-temperature H-1 NMR spectra, in four solvents, the thermodynamic parameters of I reversible arrow II exchange process were assessed. Energy of activation of I -- gt II reaction was obtained by dynamic NMR simulations for both compounds. Results revealed that conformational exchange of lactones 1 and 2 occurs due to "chair reversible arrow twisted chair" interconversion of a heptane ring. The same PM3 semiempirical method was applied for geometry optimization of lactones 1 and 2, as well as of 9alpha-hydroxycumambrine A 3, 9alpha-acetoxycumambrine B 4, and cumambrine B 5.

Chicory (Cichorium intybus L) is rich in bitter sesquiterpene lactones, mainly guaianolides: lactucin, 8-deoxylactucin, lactupicrin and their 11(S),13-dihydroderivatives-compounds recognized for their antimicrobial and anti-cancer effects. In vitro plant tissue culture, and particularly Agro bacterium rhizogeries-generated hairy root (HR) cultures, have many advantages as systems for production of valuable secondary metabolites. Although chicory HRs grow better than control culture, having nearly 60 times greater fresh weight gain, they do not contain a higher content of guaianolides than wild type (wt) roots. Thus we have established in vitro system comprised of wt root and HR cultures, and wt and transformed regenerated plants of the same age, in rosette and flowering stage, in order to study the effects of transformation, organogenesis and flowering on guaianolides production. Both regeneration and flowering in vitro were spontaneous, so the results were not influenced by exogenous growth regulators. Some of the transformed clones grew better, but all flowered earlier in comparison to wt plants. Floral transition increased guaianolides content in both roots and leaves of transformed, but not of wt plants. Expression of RolC oncogene correlated with floral transition and with guaianolides accumulation. We propose A. rhizogenes transformed plants at the flowering stage as an alternative source of free guaianolides, where, in contrast to HRs, entire plants can be used for the extraction. (C) 2014 Elsevier B.V. All rights reserved. Serbian Ministry of Education, Science and Technological Development {[}OI 173024]; EU {[}227448]

A new guaianolide, 3-deacetyl-9-O-acetylsalograviolide A, along with four known closely related lactones, salograviolide A, 9-O-acetylsalograviolide A, kandavanolide and salograviolide B were detected in the aerial parts of the flowering plant Centaurea nicolai. Antifungal tests performed on salograviolide A and its 9-O-acetyl and 3-O-deacetyl-9-O-acetyl derivatives revealed inhibitory activity against Aspergillus niger, A. ochraceus, Penticillium ochrochloron,Cladosporium cladosporodies, Fusharium tricinctum and Phomopsis helianthi. Neither of them was active against Trichoderma viride. (C) 1999 Elsevier Science Ltd. All rights reserved. null

Medicinal plants play a crucial role in traditional medicine and in the maintenance of human health worldwide. Sesquiterpene lactones represent an interesting group of plant-derived compounds that are currently being tested as lead drugs in cancer clinical trials. Achillea falcata is a medicinal plant indigenous to the Middle Eastern region and belongs to the Asteraceae family, which is known to be rich in sesquiterpene lactones. We subjected Achillea falcata extracts to bioassay-guided fractionation against the growth of HCT-116 colorectal cancer cells and identified four secotanapartholides, namely 3-β-methoxy- isosecotanapartholide (1), isosecotanapartholide (2), tanaphallin (3), and 8-hydroxy-3-methoxyisosecotanapartholide (4). Three highly oxygenated guaianolides were isolated for the first time from Achillea falcata, namely rupin A (5), chrysartemin B (6), and 1β, 2β-epoxy- 3β,4α,10α-trihydroxyguaian- 6α,12-olide (7). These sesquiterpene lactones showed no or minor cytotoxicity while exhibiting promising anticancer effects against HCT-116 cells. Further structure-activity relationship studies related the bioactivity of the tested compounds to their skeleton, their lipophilicity, and to the type of functional groups neighboring the main alkylating center of the molecule.

Commercially available santonin was used to synthesize seven sesquiterpene lactones using a facile strategy that involved a high-yielding photochemical reaction. Three natural products from Artemisia gorgonum were synthesized in good yields, and in the case of two compounds, absolute configurations were determined from X-ray quality crystals. The structures previously reported for these compounds were revised. Sesquiterpene lactones were tested using the etiolated wheat coleoptile bioassay, and the most active compounds were assayed in standard target species. seco-Guaianolide (4) showed higher phytotoxic activities than the known herbicide Logran. This high activity could be due to the presence of a cyclopentenedione ring. These results suggest that compound 4 should be involved in defense of A. gorgorum, displaying a wide range of activities that allow proposing them as new leads for development of a natural herbicide model with a seco-guaianolide skeleton.

The aerial parts of Tanacetum densum subsp. sivasicum yielded, in addition to known compounds, a new sesquiterpene lactone, sivasinolide which showed antibacterial activity against Bacillus subtilis and Klebsiella pneumoniae. The structures were elucidated by spectral methods. Some sesquiterpene lactones were evaluated for their cytotoxic activity. © 1992., University of Illinois at Chicago, Acknowledgements-The authorst hank Prof. Dr S. A. Matlin (City University,L ondon)f or theH RMS and Dr BayramY ddlz (Iniinii University,M alatya)f or his helpd uringp lantc ollection. Part of this work (at UIC) was supportedb y a grantf rom the NationalC ancerI nstitute,B ethesdaM, D.

In this study 10 guaianolide-type sesquiterpene gamma-lactones named amphoricarpolides, isolated from the aerial parts of two endemic subspecies of Amphoricarpos neumayeri (ssp. neumayeri and ssp. murbeckii Bosnjak), were investigated by means of reversed-phase thin-layer chromatography. Methanol-water and tetrahydrofuran-water binary mixtures were used as mobile phase in order to determine lipophilicity parameters R(M)(0) and C(0). Some of the investigated compounds were screened for their cytotoxic activity against HeLa and B16 cells. Chromatographically obtained lipophilicity parameters were correlated with calculated logP values and IC(50) values. Principal component analysis identified the dominant pattern in the chromatographically obtained data. Copyright (C) 2008 John Wiley & Sons, Ltd.

International audience; A promising synthetic route towards bioactive guaianolide sesquiterpene lactones is presented. The strategy is based on a recently invented multicomponent reaction (MARDi cascade) and subsequent highly chemoselective and domino transformations for the expeditious stereoselective preparation of the tricyclic core of the natural products.

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 (9 alpha-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. (c) 2006 Elsevier Ltd. All rights reserved.

A facile synthesis of a 5,7,5-fused ring system that is present in thapsigargins belonging to a novel family of sesquiterpene lactones, guainanolides, using domino enyne-RCM is reported here.

Quantitative H-1 NMR measurements revealed Delta(11(13)) sesquiterpene gamma-lactones as the main constituents (greater than or equal to 1% per weight of dried plant material) in the crude extracts of the aerial parts of Amphoricarpos neumayeri ssp. neumayeri and ssp. murbeckii from mountains Orjen and Visitor (Montenegro), respectively. Preparative silica gel chromatography afforded thirteen guai-11(13)-en-12,6alpha-olides, named amphoricarpolides (1-13), with the same relative (1alphaH,4PH,5alphaH,7betaH) configuration of the basic skeleton. The common structural feature of lactones 2-13 was 3beta,15-dioxygenation pattern. The only exception was 1 (3-deoxyamphoricarpolide), containing a single oxygen substituent (15-OH). Eight of them exhibited an additional oxygen substituent, 9beta-OH (5 and 6), 2alpha-OH (8-12), or 2alpha-OAc (13). Compound 7 was epoxydated at 10alpha(14)-position, whereas the remaining lactones contained a 10(14) double bond. (C) 2004 Elsevier Ltd. All rights reserved. Link to erratum: [https://cherry.chem.bg.ac.rs/handle/123456789/686]

Two new guaianolides, i.e. anthemolide B and 8-O-angeloyl-9-O-acetylanethemolide B, in addition to 12 known closely related guaianolides were identified in the aerial parts of the flowering plant Anthemis cretica subsp. cretica. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.

The isolation of three highly oxygenated guaianolides, desacetyl-1α-4α- dihydroxybishopsolicepolide [1], its 4β-hydroxy epimer 2 (a new compound), and 1β,2β:3β,4β-diepoxy-8α,10α-dihydroxyguai-12(13)-en-12,6α-olide [3], from the aerial parts of Achillea crithmifolia is reported. Because lactone 3 was shown to be identical with rupin A, the initially proposed 1α,2α:3α,4α-diepoxy stereochemistry of rupin A should be revised.

Three sesquiterpene lactones were isolated from the aerial parts of Centaurea sinaica : amberboin, chlorohyssopifolin A and sinaicin. The latter is reported for the first time.

Achillea crithmifolia Waldst. et Kit. (Asteraceae) is used in folk medicine against the same disorders as the well known Achillea millefolium L. (Asteraceae). Hitherto, four guaianolides (rupicolin-A and -B and their acetates), a germacranolide [1beta,10alpha-epoxy-3beta,9beta-diacetoxy-11alpha, 13-dihydrocostunolide], and a known flavonoid, jaceidin, were isolated from the CHCl3 extract of the aerial parts of A. crithmfolia, collected at the Ranj mountain (Serbia).

The extract of the aerial parts of Viguiera sylvatica gave, in addition to known heliangolides, four new heliangolides related to 1-desoxyniveusin A and one to 11,13-dihydrofuroheliangolide as well as three guaianolides, two of them derived from arbiglovin and one from estafiatin. Furthermore, two unreported geranyl nerol derivatives were isolated. The structures were elucidated by high field NMR spectroscopy. UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Química

Two sesquiterpene lactones, the new guainolide subexpinnatin and aguerin B, were isolated from the aerial part of Centaurea canariensis.