Sequiterpene Lactones Research Articles

Identification of Chemical Constituents in Zhizhu Pills Based on UPLC-QTOF-MSE.

Zhizhu pills (ZZP) are a traditional Chinese medicine (TCM) prescription, mainly used for clinically treating digestive diseases such as functional dyspepsia, constipation, and peptic ulcer. However, the chemical constituents of ZZP have rarely been reported. To establish an ultrahigh-performance liquid chromatography-quadrupole time of flight-mass spectrometry (UPLC-QTOF-MSE) method for the identification of chemical constituents in ZZP, including individual herbs and a complicated Chinese medicinal formula. The extracts of ZZP and its individual herb samples were analyzed by a UPLC-QTOF-MSE method on an ACQUITY UPLC HSS T3 column (100 × 2.1 mm id, 1.8 μm particle size) using a gradient elution of 0.1% formic acid in acetonitrile - 0.1% formic acid water (v/v) at a constant flow rate of 0.4 mL/min. With the MSE technique, both precursor ion and fragmentation information of compounds can be simultaneously acquired by alternating between low and high collision energy during a single chromatographic run. The data were analyzed on UNIFI. A total of 154 compounds, including 67 flavonoids, 17 coumarins, 11 terpenoids, 10 alkaloids, six limonoids, six sequiterpene lactones, and 37 other components, were ultimately identified based on accurate masses and fragmentation patterns in ZZP and its individual herbs. This paper summarized fragmentation patterns of flavonoids, sequiterpene lactones, alkaloids, coumarins, and limonoids. A rapid, accurate, and comprehensive UPLC-QTOF-MSE method has been developed for the identification of chemical compounds and applied to simultaneously evaluate the quality and effectiveness of ZZP. A total of 154 compounds were ultimately identified in ZZP and its individual herbs by UPLC-QTOF-MSE; the fragmentation patterns of flavonoids, sequiterpene lactones, alkaloids, coumarins, and limonoids in ZZP and its individual herbs are summarized.

In-silico and Molecular Docking Studies on Germacrene A Synthase enzyme and sesuiterpene lactone (Lactucin) involved in antimalarial activity of Cichorium intybus

Cichorium intybus, commonly known as Chicory, is a perennial herb with immense ethanomedical activity and being used in folklore medicine. Due to the presence of ample lactone, this plant has anti-malarial activity. The biosynthesis pathway of sequiterpene lactone (lactucin), which is considered to provide antimalarial activity to the plant, has Germacrene A Synthase as novel rate-limiting enzyme. This study demonstrates the structural and physiochemical properties of the enzyme Germacrene A Synthase through various bioinformatics approaches along with the docking studies. Through the in silico studies it was found that Germacrene A synthase protein interact with the lactucin with the lower energy − 7.3 kcal/mol and total 3 hydrogen bonds were formed by the Germacrene A Synthase at Gly45, Leu46, Tyr246 respectively while Leu41, Glu47, Tyr49, Asn43, Asp42, Ala50, Gln250, Leu249 amino acid residues act together through hydrophobic interactions. It was also found that the Hsp 90 protein of malaria parasite bound with lactucin with lower binding energy i.e. -5.5 kcal/mol. Two domain named terpene synthase has been determined which were found actively participate in the lactucin formation. Through CELLO, cellular localization of protein has been determined in the cytoplasm with maximum score of 2.829. The phylogenetic analysis showed that Germacrene A Synthase enzyme of chicory showing higher similarity with the Germacrene A synthase of Chichorium endivia and Lactuca sativa. Molecular docking results of lactucin and Hsp 90 protein of malarial parasites proceeding clinical trials with lactucin may give the more clue and justification for the active participation of lactucin as antimalarial compound. This study is progressively useful for further wet lab experiments and more in silico analysis to discover the mechanism of lactucin regulation by Germacrene A Synthase enzyme and also to analyze another regulating enzyme or the last enzyme involved in lactucin biosynthesis.

Biomedical Properties and Origins of Sesquiterpene Lactones, with a Focus on Dehydroleucodine

Dehydroleucodine, a sesquiterpene lactone, belongs to the terpenoid class of secondary metabolites. Dehydroleucodine and other Artemisia-derived phytochemicals evolved numerous biodefenses that were first co-opted for human pharmacological use by traditional cultures in the Middle East, Asia, Europe and the Americas. Later, these phytochemicals were modified through the use of medicinal chemical techniques to increase their potency. All sesquiterpene lactones contain an α-methylene-γ-lactone group, which confers thiol reactivity, which is responsible, in part, for their therapeutic effects. A wide range of therapeutic uses of sequiterpene lactones has been found, including anti-adipogenic, cytoprotective, anti-microbial, anti-viral, anti-fungal, anti-malarial and, anti-migraine effects. Dehydroleucodine significantly inhibits differentiation of murine preadipocytes and also significantly decreases the accumulation of lipid content by a dramatic down regulation of adipogenic-specific transcriptional factors PPARγ and C-EBPα. Dehydroleucodine also inhibits secretion of matrix metalloprotease-2 (MMP-2), which is a known protease involved in migration and invasion of B16 cells. In addition to these anti-adipogenic and anti-cancer effects, dehydroleucodine effectively neutralizes several bacterial species, including Bacillus cereus, Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Helicobacter pylori, methicillin resistant Staphylococcus aueus (MRSA) and S. epidermis (MRSE). The compound also inhibits the growth and secretion of several toxins of Pseudomonas aeruginosa, possesses gastro-protective qualities and possesses anti-parasitic properties against Trypanosoma cruzi, responsible for Chagas disease. Other sesquiterpene lactones, such as parthenolide, costunolide, and helanin, also possess significant therapeutic utility.

Major components of Spanish cultivated Artemisia absinthium populations: Antifeedant, antiparasitic, and antioxidant effects

The objective of this study was the valorization of Spanish Artemisia absinthium populations from Teruel (Aragón) and Sierra Nevada (Granada). These populations were experimentally cultivated in the field and under controlled conditions. Three major components were isolated from a two year-old population obtained from the Teruel population cultivated in Ejea-Zaragoza in 2003, and identified by NMR experiments as the sequiterpene lactone hydroxypelenolide (I) and the flavones artemetin (II) and casticin (III). The I–III content of the plant extracts was analyzed by HPLC-DAD. The insect antifeedant properties of plant extracts from different years and crops were tested against Spodoptera littoralis, Myzus persicae and Rhopalosiphum padi. Additionally we studied their antioxidant, phytotoxic and antiparasitic effects.

A study on the regenerative potential of the root and leaf extracts of Elephantopus scaber L.: An antidiabetic approachats through up-regulated heme oxygenase-1 (HO-1) expression

Ayurveda and other Indian literatures mentioned the use of plants in the treatment of various human ailments. Plants have been used by man as natural remedies from time immemorial.Elephantopus scaber L., belonging to the family Asteraceae, is a small perennial herb located in tropical climates. Anachuvady as it is called literally means “elephant’s foot”. Its leaves seem to grow as a bunch protruding from a point at the bottom. The leaves and the roots are used in treating diahorrea, liver disorders, tumors, inflammations and ulcers. Our present study indicates that the root and leaves of E. scaber (ES) can be used as a potent antihypergycemic agent. The phytochemical constituents of this plant indicate that it contains sequiterpene lactones, terpenoids, deoxyelephantopin, isodeoxyelephantopin and scab-ertopin. The crude extract of the leaf and root were prepared and Type I diabetes was experimentally induced in white albino Wistar rats (60 mg/kg body weight), after which they were divided into 9 groups of 6 rats each and analysed for various biological assays. They were later subjected to histopathological studies for investigating the regenerative potential of the plant. ES extracts reduced the blood glucose level, glycosylated hemoglobin, a change in the lipid profile and kidney functions, liver and muscle glycogen, serum insulin levels and histopathological studies. We conclude that ES extracts possess regenerative properties which are exhibited in the destructed pancreas and ethyl acetate root extract and methanol leaf extract of E. scaber L. However, they performed better as compared to other extracts, which paved way for further research in bringing about a permanent remedy for diabetes. Key words: Elephantopus scaber L., streptozotocin, hypoglycemic, glycosylated hemoglobin (HBA1C), serum insulin, liver and muscle glycogen, plasma glucose, lipid profile and kidney function tests, regeneration.

Store‐operated channels: mechanisms and function

For many years, how Ca2+ entered non-excitable cells remained enigmatic. There was a suspicion that Ca2+ channels were involved, but what these were and how they were gated was unclear. By contrast, not only were the Ca2+ channels expressed in excitable cells well defined electrophysiologically but their subunit composition and even structure–function profile had been teased apart. This imbalance began to change in 1986, when a landmark paper by James Putney let to a paradigmatic shift in our understanding of Ca2+ entry in non-excitable cells (Putney, 1986). In that classic review, Putney proposed the concept of capacitative (now called store-operated) Ca2+ influx. In its most fundamental form, emptying of agonist-sensitive intracellular Ca2+ stores led to the opening of plasma membrane Ca2+ channels. Although this model was largely overlooked in its early days, two subsequent discoveries established its importance in cell physiology. First was the finding that thapsigargin, a sequiterpene lactone occurring naturally in plants, blocked Ca2+ pumps on the stores and therefore depleted them of Ca2+. Crucially, after store depletion to thapsigargin, Ca2+ influx occurred (Takemura et al. 1989). This supported the key tenet of the store-operated model. Second and more crucially perhaps, an elegant series of patch clamp experiments by Hoth & Penner (1992) revealed the presence of a Ca2+-selective current that was activated on emptying intracellular stores. The underlying channels, which they called Ca2+ release-activated Ca2+ (CRAC) channels, could be activated regardless of how stores were emptied and provided a key electrophysiological signature for store-operated Ca2+ entry. CRAC channels have several intriguing features for ion channels including a tiny single channel conductance and exquisite selectivity for Ca2+ (reviewed in Parekh & Putney, 2005), but for many years the vexing question that engaged most researchers was the molecular basis of store-operated entry. How is Ca2+ sensed within the endoplasmic reticular Ca2+ store? How is information sent from the store to the plasma membrane? What is the molecular identity of the CRAC channel? Our understanding of store-operated Ca2+ has increased over the past three years with the identification, using primarily siRNA technology, of two key components: STIM1 and Orai1–3 (reviewed in Lewis, 2007). The pace has been breathtaking, and a picture has emerged based on solid experimental evidence from several laboratories. STIM1 is the Ca2+ sensor and Orai1 is all or part of the CRAC channel pore. Upon store depletion, STIM1 molecules migrate to form discrete puncta just below the plasma membrane where they recruit and activate Orai1. At a recent meeting of the Biophysical Society in Long Beach, California, The Journal of Physiology held a symposium entitled ‘Store-operated channels: mechanism and function’. This provided an opportunity to reflect on the recent rapid progress in the field and identify new avenues for research. Victoria Bolotina (Boston) described her recent work suggesting that a small diffusible messenger called Ca2+ influx factor (CIF) linked STIM1 to Orai1 channel activation and that STIM1 might function as an enzyme that produces CIF (Bolotina, 2008). Richard Lewis (Stanford) described how STIM1 movement to specialized ER–PM junctions occurred and that STIM1 oligomerization was sufficient to activate CRAC channels. Anant Parekh (Oxford) showed data documenting that local Ca2+ rises near CRAC channels could drive the synthesis of intra- and intercellular signalling molecules and reported the underlying signalling cascades (Parekh, 2008). Reinhold Penner (Hawaii) compared the properties of Orai1, 2 and 3 and found striking differences in how the pharmacological tool 2-APB interacted with the channels, revealing differences in channel gating (Peinelt et al. 2008). Finally, James Putney (NIEHS, Research Triangle Park) provided convincing evidence that Ca2+ influx through CRAC channels supported intracellular Ca2+ oscillations in response to low concentrations of agonist and presented data showing oscillatory movement of STIM1 up to the plasma membrane in parallel with the Ca2+ spikes (Putney & Bird, 2008). The talks presented at the symposium have been included as a series of Symposium Reviews and related research papers in this issue. In short, the symposium showed how far the store-operated channel field has advanced in a relatively short time. No doubt, with the approaches and techniques now available, new findings and unexpected twists will be revealed in the future.

Antiprotozoal activity of sequiterpene lactones – modelling of biological target properties and quantitative structure-activity relationships

In continuation of earlier studies where we found a high activity of some sesquiterpene lactones (STL) against Trypanosoma brucei rhodesiense (causing East African sleeping sickness) [1, 2], we have now conducted a structure-activity study on a set of 39 STL against T. brucei rhodesiense, T. cruzi, Leishmania donovani and Plasmodium falciparum. Furthermore, cytotoxic activity against murine cells was assessed. Some of the compounds possess high activity, especially against T. brucei (e.g. helenalin and some of its esters with IC50-values of 0.05–0.1µM which is about 10 times lower than their cytotoxic activity). The accumulated data clearly show that antiprotozoal activity is governed at least in part by different structural features than the cytotoxic effect against mammalian cells. In order to illuminate such factors underlying the observed selectivity, a QSAR study was conducted using the program Quasar [3]. This program constructs hypothetical surfaces of the presumed biological target based on the superimposed 3D molecular structures of the compounds. A Quasar model correlates the computed binding affinities of the ligands to the receptor surface with their experimental bioactivity data. Since the molecular mechanism underlying the studied activities is presumed to be related to covalent modification of the target by Michael addition, the standard setup of Quasar was modified by including the energy of each compound's lowest unoccupied molecular orbital (εLUMO) as a descriptor of electrophilic reactivity. Models of good to excellent descriptive and predictive quality could be obtained for the T. brucei and cytotoxicity data. Models for the other mentioned bioactivities are still under development.

Analysis of sesquiterpene lactones inMagnolia grandiflora L. by Micellar electrokinetic capillary chromatography

Five sequiterpene lactones found inMagnolia grandiflora were successfully separated by micellar electrokinetic capillary chromatography (MECC). Separation parameters were studied systematically, and the best results were obtained with a phosphate-borate buffer at pH 7.25, containing the bile salt sodium cholate as surfactant and isopropanol as organic modifier. Optimum temperature, voltage and detection wavelength were 30°C, 20 kV and 210 nm, respectively. This setup allowed a baseline separation of the standard compounds within 12 min, with a detection limit of 4.7 μg·mL−1 or less. A quantitative analysis of differentM. grandiflora samples showed parthenolide as the most dominant sesquiterpene lactone in all specimens, with concentrations ranging from 0.019% in fruits to 0.335% in leaves (w/w).

Sesquiterpene Lactones Specifically Inhibit Activation of NF-κB by Preventing the Degradation of IκB-α and IκB-β

Extracts from certain Mexican Indian medicinal plants used in traditional indigenous medicine for the treatment of inflammations contain sequiterpene lactones (SLs), which specifically inhibit the transcription factor NF-kappa B (Bork, P. M., Schmitz, M. L., Kuhnt, M., Escher, C., and Heinrich, M. (1997) FEBS Lett. 402, 85-90). Here we show that SLs prevented the activation of NF-kappa B by different stimuli such as phorbol esters, tumor necrosis factor-alpha, ligation of the T-cell receptor, and hydrogen peroxide in various cell types. Treatment of cells with SLs prevented the induced degradation of I kappa B-alpha and I kappa B-beta by all these stimuli, suggesting that they interfere with a rather common step in the activation of NF-kappa B. SLs did neither interfere with DNA binding activity of activated NF-kappa B nor with the activity of the protein tyrosine kinases p59fyn and p60arc. Micromolar amounts of SLs prevented the induced expression of the NF-kappa B target gene intracellular adhesion molecule 1. Inhibition of NF-kappa B by SLs resulted in an enhanced cell killing of murine fibroblast cells by tumor necrosis factor-alpha. SLs lacking an exomethylene group in conjugation with the lactone function displayed no inhibitory activity on NF-kappa B. The analysis of the cellular redox state by fluorescence-activated cell sorter showed that the SLs had no direct or indirect anti-oxidant properties.

Theoretical studies of some new Anti-Malarial drugs

Qinghaosu (Artemisinin), is a sequiterpene lactone containing a peroxide group, which has been used from ancient times as an anti-malarial agent in Chinese medicine [1]. Unlike chloroquine and related compounds used as anti-malarial agents, resistant strains of malaria have not developed so far to qinghaosu. In this article; we present the results of a theoretical study of the structure of this and related molecules, using both semi-empirical and ab-initio quantum chemical methods, and an investigation of the known structure/activity (S/A) relationships of Qinghaosu and related molecules as anti-malarials using Molecular Electrostatic Potential (MEP) maps. The unusual 1,2,4-trioxane ring system, and other ring systems containing the peroxide linkage occurring in qinghaosu have also been studied in some detail. We speculate that the reactivity of this system in this context is related to a rather dramatic region of negative potential that surrounds the molecule and that includes the OO linkage as well as the ring oxygen atom.

Structures of anislactone A and B; Novel type of sequiterpene lactones from the pericarps of Illicium anisatum.

Two new sesquiterpene lactones, named anislactone A and B, were isolated from the pericarps of Illicium anisatum.The structure of anislactone A was established by X-ray crystallographic analysis. Anislactone B was the isomer of anislactone A, and its structure was determined by spectral data compared with those of anislactone A. They were considered to be the biological derivatives from anisatin of its derivative.

Molecular and crystal structure of the sequiterpene lactone austricin

An x-ray structural study has been made of the sesquiterpene lactone austricin: diffractometer, MoKα radiation, 1147 reflections, direct method, R=0.045. The spatial structure of the molecule has been determined. The conformation of the pentane carbocycle is 1α-envelope, of the heptane ring 1,10β, 7α-chair, and of the lactone ring 7α-envelope. The lactone ring is trans-linked with the guaiane skeleton.

Toxicity and mutagenicity of hymenoxon, a sequiterpene lactone

The oral LD 50 of hymenoxon in Swiss white mice was found to be 241 ± 37 mg/kg. No significant sex differences were observed. Pretreatment of male mice for 3 days using doses of 50 and 100 mg/kg hymenoxon failed to alter significantly pentobarbital sleeping time. Hymenoxon was found to be a direct-acting mutagen in the Salmonella/mammalian microsome test. Urine samples obtained from hymenoxon-treated mice were found to be negative for mutagenic activity when tested directly and when incubated with β-glucuronidase. Hymenoxon did not produce lethal DNA damage as measured in the Escherichia coli polA or Bacillus subtilis recombinational assays.

Systematic implications of sesquiterpene lactones in the subtribe melampodiinae

Within the tribe Heliantheae of the Asteraceae, the genetic boundaries of the subtribe Melampodinae have recently been drastically revised by Stuessy. The number of genera within the subtribe has been reduced and new generic groupings have been established. The present study correlates the distribution of sesquiterpene lactones found in these genera with the newly revised subtribal boundaries. The genera Acanthospermum, Melampodium, Polymnia and Sigesbeckia produce predominantly melampolide-type sequiterpene lactones. Limited chemical data support Stuessy's removal of the genera Desmanthodium, Clibadium and Ichthyothere from the subtribe Melampodiinae. The occurrence of melampolide-type sesquiterpene lactones in members of the genera Tetragonotheca (Helianthinae) and Enhydra (Ecliptinae) indicate a possible position of these genera in the Melampodiinae.