Echinacea Pallida Research Articles

Biotechnological production of caffeic acid derivatives from cell and organ cultures of Echinacea species.

Caffeic acid derivatives (CADs) are a group of bioactive compounds which are produced in Echinacea species especially Echinacea purpurea, Echinacea angustifolia, and Echinacea pallida. Echinacea is a popular herbal medicine used in the treatment of common cold and it is also a prominent dietary supplement used throughout the world. Caffeic acid, chlorogenic acid (5-O-caffeoylquinic acid), caftaric acid (2-O-caffeoyltartaric acid), cichoric acid (2, 3-O-dicaffeoyltartaric acid), cynarin, and echinacoside are some of the important CADs which have varied pharmacological activities. The concentrations of these bioactive compounds are species specific and also they vary considerably with the cultivated Echinacea species due to geographical location, stage of development, time of harvest, and growth conditions. Due to these reasons, plant cell and organ cultures have become attractive alternative for the production of biomass and caffeic acid derivatives. Adventitious and hairy roots have been induced in E. pupurea and E. angustifolia, and suspension cultures have been established from flask to bioreactor scale for the production of biomass and CADs. Tremendous progress has been made in this area; various bioprocess methods and strategies have been developed for constant high-quality productivity of biomass and secondary products. This review is aimed to discuss biotechnological methods and approaches employed for the sustainable production of CADs.

Making sense of a prairie butterfly paradox: The effects of grazing, time since fire, and sampling period on regal fritillary abundance

Although grasslands often require periodic disturbance to prevent woody plant invasion, some grassland-obligate butterfly species respond negatively to disturbance agents such as fire and grazing. We examined the effects of time since fire, grazing and sampling period on abundance of a grassland-obligate butterfly, the regal fritillary (Speyeria idalia), at four grassland sites in Missouri, USA. Each site consisted of two pastures: one managed with patch-burn grazing (rotational burning plus cattle), and one managed with rotational burning but lacking cattle. Population density was assessed via line transect distance sampling in three periods of 2006 and 2007. Floral resource availability was measured in 2007. Grazing and time since fire interacted in their effects on regal fritillary density in 2006, as grazing reduced density in patches burned earlier that year but not in patches burned 1 or 2years prior. In 2007, regal fritillary density was a function of a three-way interaction. In recently burned patches, grazing reduced regal fritillary density and flowering stem density of two preferred nectar sources in early June and late July. In ungrazed pastures, recent fire increased density of regal fritillary and the same preferred nectar sources. Densities of regal fritillary and Echinacea pallida were positively correlated in early June, as were densities of regal fritillary and Liatris pycnostachya in late July, suggesting that regal fritillary adults recolonized recently burned prairie to use those nectar sources. Our research illustrates that prescribed fire can be compatible with grassland butterfly conservation.

Echinacea sanguinea and Echinacea pallida extracts stimulate glucuronidation and basolateral transfer of Bauer alkamides 8 and 10 and ketone 24 and inhibit P-glycoprotein transporter in Caco-2 cells.

The use of Echinacea as a medicinal herb is prominent in the United States, and many studies have assessed the effectiveness of Echinacea as an immunomodulator. We hypothesized that Bauer alkamides 8, 10, and 11 and ketone 24 were absorbed similarly either as pure compounds or from Echinacea sanguinea and Echinacea pallida ethanol extracts, and that these Echinacea extracts could inhibit the P-glycoprotein transporter in Caco-2 human intestinal epithelial cells. Using HPLC analysis, the permeation rate of Bauer alkamides by passive diffusion across Caco-2 cells corresponded with compound hydrophilicity (alkamide 8 > 10 > 11), independent of the plant extract matrix. Both Echinacea ethanol extracts stimulated apparent glucuronidation and basolateral efflux of glucuronides of alkamides 8 and 10 but not alkamide 11. Bauer ketone 24 was totally metabolized to more hydrophilic metabolites when administered as a single compound, but was also glucuronidated when present in Echinacea extracts. Bauer alkamides 8, 10, and 11 (175-230 µM) and ethanol extracts of E. sanguinea (1 mg/mL, containing ~ 90 µM total alkamides) and E. pallida (5 mg/mL, containing 285 µM total alkamides) decreased the efflux of the P-glycoprotein transporter probe calcein-AM from Caco-2 cells. These results suggest that other constituents in these Echinacea extracts facilitated the metabolism and efflux of alkamides and ketones, which might improve therapeutic benefits. Alkamides and Echinacea extracts might be useful in potentiating some chemotherapeutics, which are substrates for the P-glycoprotein transporter.

Induction of adventitious roots of Echinacea pallida and accumulation of caffeic acid derivatives

To investigate the effect of auxins 2,4-D,IAA,IBA,NAA on induction of adventitious roots as well as that of IBA concentrations on the growth of adventitious roots and the accumulation of caffeic acid derivatives, with test-tube seedling leaves Echinacea pallida as the explant, and cultivate adventitious roots in bioreactors. 1.0 mg x L(-1) IBA was found the best for the induction of adventitious roots, with the numer of induced adventitious roots up to 22. 5 in each culture dish. Among different concentrations for suspension cultivation of IBA tested, 1.0 mg x L(-1) IBA was found the most suitable for the growth of adventitious roots and the accumulation of caffeic acid derivatives. In a 5 L balloon type bubble bioreactor, 8.98 g x L(-1) dry weight was achieved after one month, which was 2.05 times of 4.38 g x L(-1) dry weight cultivated in a triangular flask. The content of echinacoside cultivated in a bioreactor was 14.08 mg x g(-1) DW, which was 2.4 times of cultivated roots. The contents of chlorogenic acid, chicoric acid and total caffeic acid derivatives were 4.0-25.6 times of ultivated roots. The study can provide high-quality biomedical drugs containing such caffeic acid derivatives as echinacoside for mass production of Echinacea purpurea medicines.

Seasonal Variations in the Concentrations of Lipophilic Compounds and Phenolic Acids in the Roots of Echinacea purpurea and Echinacea pallida

Roots of Echinacea purpurea and Echinacea pallida cultivated for 4 years in a North European climate were analyzed for seasonal variations in the concentrations of lipophilic constituents (alkamides, ketoalkenes, and ketoalkynes) and phenolic acids by harvesting five times during 1 year to establish the optimal time for harvest. A total of 16 alkamides, three ketoalkenes, two ketoalkynes, and four phenolic acids (echinacoside, cichoric acid, caftaric acid, and chlorogenic acid) were identified in aqueous ethanolic (70%) extracts by liquid chromatography-mass spectrometry and quantified by reverse-phase high-performance liquid chromatography. The major alkamides in the roots of E. purpurea were at their lowest concentration in the middle of autumn and early winter, and the total concentration of lipophilic compounds in E. pallida showed the same pattern. Moreover, all of the major phenolic acids in E. purpurea were at their highest concentrations in spring. The optimal harvest time in spring is in contrast to normal growing guidelines; hence, this specific information of seasonal variations in the concentrations of lipophilic and phenolic compounds in E. purpurea and E. pallida is valuable for research, farmers, and producers of medicinal preparations.

Antiproliferative activity of pentadeca-(8E, 13Z) dien-11-yn-2-one and (E)-1,8-pentadecadiene from Echinacea pallida (Nutt.) Nutt. roots

Several species of Echinacea, a perennial plant which belongs to the Asteraceae family, possess medicinal properties and are currently used in phytotherapy. In the present study, antiproliferative activity of methanol extract and isolated structures of pentadeca-(8E, 13Z)-dien-11-yn-2-one 1 and (E)-1,8-pentadecadiene 2 from Echinacea pallida roots on C6 cells (Rat Brain tumor cells) and HeLa cells (human uterus carcinoma) was investigated in vitro. Antiproliferative effect of the extract, isolated compounds, and cisplatin were tested at 5, 10, 20, 30, 40, 50, 75, and 100 μg ml−1 using BrdU Cell Proliferation ELISA. The methanol extract and Compound 1 significantly inhibited proliferation of HeLa and C6 cancer cell lines.

Antioxidant addition to prevent lipid and protein oxidation in chicken meat mixed with supercritical extracts of Echinacea angustifolia

Lipid and protein oxidation is a major phenomenon reducing meat quality during cooking and storage and leading to off-flavour formation and rancidity. The use of vegetable extracts to increase shelf life is a promising new frontier in the prevention of oxidation. In this study the efficacy on lipid and protein oxidation was evaluated in chicken meat mixed with conventional methanol/water and supercritical extracts of Echinacea angustifolia after cooking and at different times of cold storage in order to propose these matrices as natural substances to increase the shelf-life of meat products. Echinacea spp. are native to North America and were traditionally used by the Indian tribes for a variety of diseases, including mouth sores, colds and snakebites. The three most commonly used Echinacea spp. are Echinacea angustifolia, Echinacea pallida and Echinacea purpurea. In particular, a series of experiments have shown that E. angustifolia extracts have significant immunomodulatory activities. Total phenols and antioxidant activity of the SFE extracts were used as parameters to characterize the vegetable extracts, TBARS and MDA were considered to monitor lipid oxidation, while protein oxidation was measured as carbonyl compounds. Results show a protective action of plant antioxidants against oxidation, but also a greater selectivity and a higher efficiency of natural extracts obtained by SFE respect to conventional extract. The study of the metabolic profile was performed by tandem mass spectrometry (LC/MS/MS).

Comparative evaluation of growth-stimulating activity extracts of pale coneflower (Echinacea pallida (Nutt.) Nutt.) and stimulant Zircon

Comparative evaluation of growth-stimulating activity extracts of pale coneflower (Echinacea pallida (Nutt.) Nutt.) and stimulant Zircon

Simultaneous metabolite fingerprinting of hydrophilic and lipophilic compounds in Echinacea pallida by high-performance liquid chromatography with diode array and electrospray ionization-mass spectrometry detection

In this study, a detailed phytochemical characterization of Echinacea pallida (Nutt.) Nutt. root extracts and dietary supplements was carried out for the first time by developing advanced chromatographic techniques, based on HPLC with diode array (DAD) and electrospray ionization-mass spectrometry (ESI-MS) detection (with ion trap and triple quadrupole mass analyzers), for the simultaneous analysis of hydrophilic and lipophilic secondary metabolites. The HPLC analyses were carried out on an Ascentis C18 column (250mm×4.6mm I.D., 5μm), with a mobile phase composed by H2O and ACN both containing 0.1% formic acid, under gradient elution. The UV spectra, in combination with MS and MS/MS data, allowed the identification of fourteen compounds, including caffeic acid derivatives, polyacetylenes and polyenes, in the analyzed samples. MS and MS/MS data were discussed in detail and the typical fragmentation patterns of each class of secondary metabolites were identified. For the first time, a hydroperoxide intermediate was characterized as an oxidation product of one of E. pallida monocarbonylic acetylenes, providing a confirmation of the mechanism that leads to the generation of hydroxylated derivatives. The HPLC method was fully validated in agreement with ICH guidelines and then applied to real samples. The quantitative analysis indicated that there was a great variability in the amount of the active compounds in the dietary supplements containing E. pallida root extracts: the content of total caffeic acid derivatives ranged from 2.31 to 11.45mg/g and the amount of total polyacetylenes and polyenes from 6.38 to 30.54mg/g. In the analyzed samples, the most abundant caffeic acid derivative was found to be echinacoside. Regarding polyacetylenes and polyenes, the most representative compounds were found to be tetradec-(8Z)-ene-11,13-diyn-2-one, pentedeca-(8Z,11Z)-dien-2-one and pentadec-(8Z)-en-2-one. The developed method can be considered suitable for metabolite fingerprinting and quality control of E. pallida plant material and natural products.

First Report of a 16SrII-A Subgroup Phytoplasma Associated with Purple Coneflower (Echinacea purpurea) Witches'-Broom Disease in Taiwan.

Purple coneflower (Echinacea purpurea), widely grown as an ornamental and medicinal plant, is a perennial flowering plant that is native to eastern North America. In July 2011, symptoms indicative of phytoplasma disease, including floral virescence, phyllody, and witches'-broom (WB), were observed to be affecting plants in coneflower fields in Wufeng, Taichung City, Taiwan. Incidence of infected plants was estimated to be greater than 90% within a single field. Phytoplasmas previously associated with purple coneflower WB disease have all been classified as aster yellows group (16SrI) strains (GenBank Accession Nos. EU333395, AY394856, EU416172, and EF546778) except for pale purple coneflower (Echinacea pallida) WB in Australia, which was identified as a subgroup 16SrII-D member (2). Three diseased plants were uprooted and transplanted in a greenhouse for further study. Transmission electron microscopy revealed clusters of phytoplasma cells ranging from 170 to 490 nm in diameter in phloem sieve elements of virescent and phylloid flowers and stems from diseased plants. Comparable tissues from symptomless plants were devoid of phytoplasma. Total DNA was extracted from plant tissue samples (50 to 100 mg each) including stems, leaves, and flowers by a modified CTAB method (1) from three symptomatic plants as well as from three asymptomatic coneflower plants seedlings. Analyses by a nested PCR using universal primer pairs P1/P7 followed by R16F2n/R16R2 were performed to detect putative phytoplasma (2). Each primer pair amplified a single PCR product of either 1.8 or 1.2 kb, respectively, from diseased plant tissues only. The nested PCR products (1.2 kb) amplified from phylloid flowers of the three diseased plants were cloned separately and sequenced (GenBank Accession Nos. JN885460, JN885461, and JN885462). Blast analysis of the sequences revealed a 99.7 to 99.8% sequence identity with those of Echinacea WB phytoplasma strain EWB5 and EWB6 (GenBank Accession Nos. JF340076 and JF340080), which reportedly belonged to the 16SrII-D subgroup (2). Moreover, iPhyClassifier software (3) was used to perform sequence comparison and generate the virtual restriction fragment length polymorphism (RFLP) profile. The 16S rDNA sequences share a 99.4 to 99.5% similarity with that of the 'Candidatus Phytoplasma australasiae' reference strain (Y10097) and the RFLP patterns are identical to that of the 16SrII-A subgroup. Taken together, these results indicated that the phytoplasma infecting purple coneflower in Taiwan is a 'Ca. Phytoplasma australasiae'-related strain and belongs to the 16SrII-A subgroup. To our knowledge, this is the first report of a 16SrII-A subgroup phytoplasma causing WB disease on purple coneflower in Taiwan. The occurrence of phytoplasma on purple coneflower could have direct implication for the economically important ornamental, medicinal plant, and floral industry in Taiwan, especially to the growers and breeders that eagerly promote the purple coneflower industry.

Clonal propagation and production of cichoric acid in three species of Echinaceae

In vitro tissue culture protocols were tested for propagation of Echinacea purpurea, Echinacea pallida and Echinacea angustifolia in order to obtain biomass for the production of cichoric acid, which is the major active compound in the Echinacea extracts. The in vitro culture process was initiated by seed germination on half-strength Murashige and Skoog (MS) medium. Multiplication was achieved on MS medium supplemented with naphthaleneacetic acid (NAA), indole-3-butyric acid (IBA), 2-iso-pentenyladenine (2iP), and N6-benzyladenine (BA) in different concentrations. Shoot explants produced the highest number of shootlets on MS medium, which was supplemented with 0.1 mg/l 2iP and 0.1 mg/l IBA. RAPD markers revealed genetic polymorphism in some instances between in vitro generated plantlets such as for E. purpurea plantlets analyzed with the OPO-8 primer. RAPD markers generated with the primer 4A-29 revealed low levels of genetic variation between in vitro plantlets for all three species of Echinacea, while remaining RAPD markers revealed no variation. Content of cichoric acid in leaves, shoots, and callus was analyzed by high-performance liquid chromatography/MS and was identified in all studied samples, independent of species or tissue type. Highest levels (0.39–0.73 mg/g dw) were observed in shoots and leaves.

Differential physiological and biochemical responses of three Echinacea species to salinity stress

The physiological and biochemical responses of the three Echinacea species, Echinacea purpurea, Echinacea pallida and Echinacea angustifolia were evaluated in response to NaCl salinity (0, 50, 75 and 100mM) under hydroponic cultivation. Growth, injury index, gas exchange, ion accumulation, pigment content, electrolyte leakage (EL) in addition to antioxidant enzyme activities were measured after two weeks of salt treatments. Salinity did not alter the root or shoot biomass of the three Echinacea species studied. However, the survival rate varied among the species, with the highest rate (96.8%) in E. purpurea and the lowest one (70.7%) in E. angustifolia. In parallel, E. angustifolia plants showed high injury index and EL values compared to the other two species, which indicates its sensitivity to salinity-induced membrane damage even at the lowest salt concentration tested. This species showed a decrease in stomatal conductance, photosynthetic and transpiration rates at all salt concentrations; while, in E. purpurea and E. pallida, the photosynthetic rate was reduced only at 75 and 100mM NaCl. The decline in the leaf gas exchange was highly correlated with Na+ and Cl− contents in all Echinacea species. Although Na+ and Cl− concentrations increased in both roots and shoots with increasing external salt concentrations, the accumulation of Na+ ions in E. angustifolia shoots was higher than in the other two species, resulting in a significant increase in Na+/K+ ratio. Furthermore, E. purpurea retained more Na+ ions in the roots than the other species suggesting higher efficiency in excluding Na+ from the shoots. E. purpurea showed increased superoxide dismutase (SOD) and ascorbate peroxidase (APX) activities at all salt concentrations. On the other hand, salinity induced a reduction in catalase (CAT) activity with no change in glutathione reductase (GR) activity in any of the species. Our results indicate that the Echinacea species studied showed a limited salt tolerance. However, E. purpurea and to a lesser extent, E. pallida were more salt tolerant than E. angustifolia. The relative tolerance of E. purpurea was associated with the higher Na+ exclusion capacity and the increased antioxidant activities particularly SOD and APX.

Salinity-induced changes in caffeic acid derivatives, alkamides and ketones in three Echinacea species

A hydroponic study was carried out to investigate the changes in caffeic acid derivatives, alkamides and ketones in three Echinacea species in response to salinity stress (0, 50, 75 and 100 mM NaCl). These hydrophilic and lipophilic compounds were extracted from the roots by Accelerated Solvent Extractor and analyzed simultaneously by RP-HPLC. The characteristic phytochemical profile of caffeic acid derivatives, alkamides and/or ketones was not affected by salinity. However, significant changes in their relative amount were found depending on the species and salinity intensity. Two of the Echinacea species studied, Echinacea purpurea and Echinacea angustifolia exposed to salinity up to 75 mM NaCl for two weeks, had higher amount of caftaric acid, cynarin, and cichoric acid ( E. purpurea) as well as chlorogenic acid, cynarin, echinacoside, caffeic acid and alkamides 12, 13, 14/15, 16, 17, 8/9, 18 ( E. angustifolia) than the respective control plants. In contrast, in Echinacea pallida, caftaric acid, echinacoside, and major ketones 22, 24, 25 and pentadeca-8 Z, 11 Z-dien-2-one levels were reduced at 50 and/or 75 mM NaCl. The highest concentration of salt (100 mM NaCl) reduced the level of cynarin, cichoric acid, cichoric acid derivative and alkamides 1, 3, 6, 7, 8/9 in E. purpurea and caftaric acid, alkamide 2, ketones 24, 25 in E. pallida, as well as alkamides 1, 2, 11 in E. angustifolia. Our results suggest that the quality of the raw material obtained from both E. purpurea and E. angustifolia exposed to salinity up to 75 mM NaCl would be higher than the one obtained from E. pallida as the plants retained most of their phytochemical marker compounds.

Reduction of seed dormancy in Echinacea pallida (Nutt.) Nutt. by in-dark seed selection and breeding

Strong seed dormancy has been an obstacle for field production of Echinacea species. Previous research on overcoming Echinacea seed dormancy has been extensive and focused on treatment methods, which involve time and expense, and are incompatible with organic production if synthetic chemicals are used. We have attempted to genetically reduce seed dormancy through selection and breeding in Echinacea, by using Echinacea pallida as a model species. Three accessions were used in this study. Nine parent plants of each accession selected from early, in-dark germinated seeds (in-dark plants) or from late, in-light seeds (in-light plants) were planted and grouped by accession and germination treatment method for seed production through a polycross method. Germination tests indicated that these in-dark plants produced seed (in-dark seed) with significantly reduced seed dormancy when tested under light or dark condition in comparison to the seed of the in-light plants (in-light seed). Among the three accessions, the in-dark seed germinated at much higher rates than did the in-light seed, more than 2× at 25°C under light and up to an 83× increase in darkness, and up to an 8× increase over the corresponding parental seed lots under comparable germination conditions. In addition to these increases in germination, the in-dark seed showed early and synchronized germination as compared to the in-light seed. Since these results were achieved through only one cycle of selection and breeding, they strongly suggest that we have developed a very effective method for modifying seed dormancy in Echinacea.

The preparation of ketone constituents from Echinacea pallida

Efficient syntheses of two ketones from Echinacea pallida are described.

First Report of a 16SrII-D Subgroup Phytoplasma Associated with Pale Purple Coneflower Witches'-Broom Disease in Australia.

Pale purple coneflower, Echinacea pallida (Nutt.) Nutt., is an herbaceous perennial cultivated for its ornamental and medicinal properties. In 2005, phytoplasma-like symptoms, including virescence, phyllody, and chlorotic leaves, were first observed in coneflower fields in northern Tasmania, Australia. During the 2010-2011 growing season, the incidence of affected plants was estimated to be 12% within a single field. Total DNA was extracted from symptomatic plants with a DNeasy Plant Mini Kit (QIAGEN Inc., Valencia, CA) according to the manufacturer's instructions. DNA was also extracted, as described above, from asymptomatic coneflower seedlings obtained by germinating surface-sterilized seed on water agar. DNA was amplified via a nested PCR using universal primer pairs P1/P7 followed by R16F2n/R16R2 to detect putative phytoplasmas (2). Amplifications yielded expected products of 1.8 and 1.2 kb, respectively, only from symptomatic samples. Subsequently, PCR products from six arbitrarily selected samples were used for sequencing (Genome Lab Dye Terminator Cycling Sequence with Quick Start Chemistry) and read in a CEQ8000 sequencer (Beckman Coulter Inc., Brea, CA). Sequence homology indicated 100% similarity between isolates designated EWB1 to EWB4 (GenBank Accession Nos. JF340075 and JF340077 to JF340079) and between EWB5 and EWB6 (JF340076 and JF40080). Sequence homology between the two observed groups was 99.7%, resulting from a 4-bp difference in the R16F2n primer region. Blast search revealed isolates EWB1 to EWB4 were 100% homologous with Catharanthus roseus phytoplasma (EU096500.1), Tomato big bud phytoplasma (EF193359.1), Scaevola witches'-broom phytoplasma (AB257291.1), and Mollicutes sp. (Y10097.1 and Y10096.1). Moreover, isolates EWB5 and EWB6 shared 99% sequence identity with the above isolates. iPhyClassifier (4) was used to perform sequence similarity and generate virtual restriction fragment length polymorphism (RFLP) profiles. The 16S rDNA sequence of isolates EWB1 to EWB4 and EWB5 to EWB6 shared 100 and 99.7% similarity, respectively, to the 'Candidatus Phytoplasma australasiae' reference strain (Y10097). RFLP profiles from all isolates suggested that they belonged to the 16SrII-D subgroup. To our knowledge, this is the first report of a 16SrII-D subgroup phytoplasma infecting E. pallida in Australia. Aster yellow phytoplasmas (16SrI-C subgroup) infections of E. purpurea have been recorded in Slovenia (3) and southern Bohemia (1).

Temporal Changes in Morphological Traits in a Population of Echinacea pallida in the Tall Grass Prairie Preserve, Oklahoma

We analyzed the structure and spatial temporal changes of a population of Echinacea pallida in the Tall Grass Prairie Preserve of Oklahoma. Plants were classified into different categories based on total leaf length and transition probabilities for three periods (1997-1998, 1998-1999, 1999-2000) and were used to determine temporal changes. The analysis of transition probabilities among different size classes for the three periods allowed us to discriminate the transition probabilities matrices. A univariate spatial analysis of individuals showed significant aggregation for most distances greater than 40 cm; from 0 to 40 cm the spatial distribution of stems did not differ (p>0.05) from a random distribution. Aggregation increased from year 1 to year 4 of the study period, which seems to be related to an increase in density.Although we did not have a control site, results for both years with previous burning strongly suggest the effect of fire in the population dynamic.

Cannabinoid receptor activity of polyacetylenes and polyenes from Echinacea pallida

Echinacea products are among the best-selling herbal preparations in the western world, mainly used for the treatment of upper respiratory tract infections and the common cold. The fractionation of a supercritical CO2-extract of Echinacea pallida (Nutt.) Nutt. roots led to the isolation of seven polyacetylenes and polyenes. The structures were determined by UV, NMR and MS in comparison with data from literature [1], [2]. The aim of our recent study was to investigate the potential cannabinoid receptor activity of the isolated compounds on human CB1R and CB2R and compare those results with prior studies [3]. So far only alkamides have been shown to bind to the human CB2R with high affinity [4], [5]. As cannabinoid receptors couple to Gi/G0 proteins, the activity of the intrinsic GTPase can be measured using the radioactively labelled GTP derivative [γ-32P]GTP. The amount of 32Pi release allows a conclusion to be drawn about the pharmacological behaviour of the tested compound [6]. Dose-response curves focusing on CB2R activity were drawn for (8Z)-pentadeca-8,11-diene-2-one and (8Z)-pentadeca-8-ene-2-one, resulting in logEC50 values in the micromolar range (–5.66±0.27 and –5.02±0.26, respectively) and a stimulation of GTPase activity of 10%±6 and 14%±2, respectively as compared to basal GTPase activation. This is in contrast to some Echinacea alkamides that stimulated GTPase activity up to 136±14%. Observing no significant activity at either receptor, these findings support the hypothesis that polyacetylenes and polyenes do not affect the immune system via the cannabinergic system [4].

Optimization and single-laboratory validation study of a high-performance liquid chromatography (HPLC) method for the determination of phenolic Echinacea constituents

Three species of Echinacea (Echinacea purpurea, Echinacea angustifolia, and Echinacea pallida) are commonly used for medicinal purposes. The phenolic compounds caftaric acid, cichoric acid, echinacoside, cynarin, and chlorogenic acid are among the phytochemical constituents that may be responsible for the purported beneficial effects of the herb. Although methods for the analysis for these compounds have been published, documentation of their validity was inadequate as the accuracy and precision for the detection and quantification of these phenolics was not systematically determined and/or reported. To address this issue, the high-performance liquid chromatography method, originally developed by the Institute for Nutraceutical Advancement (INA), was reviewed, optimized, and validated for the detection and quantification of these phenolic compounds in Echinacea roots and aerial parts.

Cytotoxic Activity and G1 Cell Cycle Arrest of a Dienynone fromEchinacea pallida

In the present study, a further investigation of the cytotoxic activity of an acetylenic constituent of Echinacea pallida roots, namely, pentadeca-(8 Z,13 Z)-dien-11-yn-2-one, was performed, revealing a concentration-dependent cytotoxicity on several human cancer cell lines, including leukemia (Jurkat and HL-60), breast carcinoma (MCF-7), and melanoma (MeWo) cells. As part of its mechanism of action, the ability of this constituent to arrest the cell cycle in the G1 phase was demonstrated on HL-60 cells. Furthermore, a stability test of the target compound over 72 h was carried out, indicating that the cytotoxic activity can be attributed mainly to the genuine, not oxidized, molecule.