Highly Oxidized Ecdysteroids from a Commercial Cyanotis arachnoidea Root Extract as Potent Blood-Brain Barrier Protective Agents.

Ecdysteroid-containing herbal extracts, commonly prepared from the roots of Cyanotis arachnoidea, are marketed worldwide as a "green" anabolic food supplement. Herein are reported the isolation and complete 1H and 13C NMR signal assignments of three new minor ecdysteroids (compounds 2-4) from this extract. Compound 4 was identified as a possible artifact that gradually forms through the autoxidation of calonysterone. The compounds tested demonstrated a significant protective effect on the blood-brain barrier endothelial cells against oxidative stress or inflammation at a concentration of 1 µM. Based on these results, minor ecdysteroids present in food supplements may offer health benefits in various neurodegenerative disease states.

Diversity-Oriented Synthesis Catalyzed by Diethylaminosulfur-Trifluoride-Preparation of New Antitumor Ecdysteroid Derivatives.

Fluorine represents a privileged building block in pharmaceutical chemistry. Diethylaminosulfur-trifluoride (DAST) is a reagent commonly used for replacement of alcoholic hydroxyl groups with fluorine and is also known to catalyze water elimination and cyclic Beckmann-rearrangement type reactions. In this work we aimed to use DAST for diversity-oriented semisynthetic transformation of natural products bearing multiple hydroxyl groups to prepare new bioactive compounds. Four ecdysteroids, including a new constituent of Cyanotis arachnoidea, were selected as starting materials for DAST-catalyzed transformations. The newly prepared compounds represented combinations of various structural changes DAST was known to catalyze, and a unique cyclopropane ring closure that was found for the first time. Several compounds demonstrated in vitro antitumor properties. A new 17-N-acetylecdysteroid (13) exerted potent antiproliferative activity and no cytotoxicity on drug susceptible and multi-drug resistant mouse T-cell lymphoma cells. Further, compound 13 acted in significant synergism with doxorubicin without detectable direct ABCB1 inhibition. Our results demonstrate that DAST is a versatile tool for diversity-oriented synthesis to expand chemical space towards new bioactive compounds.

An integrated approach to unravel a crucial structural property required for the function of the insect steroidogenic Halloween protein Noppera-bo.

Ecdysteroids are the principal steroid hormones essential for insect development and physiology. In the last 18 years, several enzymes responsible for ecdysteroid biosynthesis encoded by Halloween genes were identified and genetically and biochemically characterized. However, the tertiary structures of these proteins have not yet been characterized. Here, we report the results of an integrated series of in silico, in vitro, and in vivo analyses of the Halloween GST protein Noppera-bo (Nobo). We determined crystal structures of Drosophila melanogaster Nobo (DmNobo) complexed with GSH and 17ß-estradiol, a DmNobo inhibitor. 17ß-Estradiol almost fully occupied the putative ligand-binding pocket and a prominent hydrogen bond formed between 17ß-estradiol and Asp-113 of DmNobo. We found that Asp-113 is essential for 17ß-estradiol-mediated inhibition of DmNobo enzymatic activity, as 17ß-estradiol did not inhibit and physically interacted less with the D113A DmNobo variant. Asp-113 is highly conserved among Nobo proteins, but not among other GSTs, implying that this residue is important for endogenous Nobo function. Indeed, a homozygous nobo allele with the D113A substitution exhibited embryonic lethality and an undifferentiated cuticle structure, a phenocopy of complete loss-of-function nobo homozygotes. These results suggest that the nobo family of GST proteins has acquired a unique amino acid residue that appears to be essential for binding an endogenous sterol substrate to regulate ecdysteroid biosynthesis. To the best of our knowledge, ours is the first study describing the structural characteristics of insect steroidogenic Halloween proteins. Our findings provide insights relevant for applied entomology to develop insecticides that specifically inhibit ecdysteroid biosynthesis.

A Commercial Extract of Cyanotis arachnoidea Roots as a Source of Unusual Ecdysteroid Derivatives with Insect Hormone Receptor Binding Activity.

Ecdysteroids act as molting hormones in insects and as nonhormonal anabolic agents and adaptogens in mammals. A wide range of ecdysteroid-containing herbal extracts are available worldwide as food supplements. The aim of this work was to study such an extract as a possible industrial source of new bioactive ecdysteroids. A large-scale chromatographic isolation was performed from an extract of Cyanotis arachnoidea roots. Ten ecdysteroids (1-10) including eight new compounds were isolated and characterized by extensive nuclear magnetic resonance studies. Highly unusual structures were identified, including a H-14ß (1, 2, 4, and 10) moiety, among which a 14ß(H)17ß(H) phytosteroid (1) is reported for the first time. Compounds with an intact side chain (4-10) and 11 other natural or semisynthetic ecdysteroids (11-21) were tested for insect ecdysteroid receptor (EcR) binding activity. Two new compounds, i.e., 14-deoxydacryhainansterone (5) and 22-oxodacryhainansterone (6), showed strong EcR binding activity (IC50 = 41.7 and 380 nM, respectively). Six compounds were identified as EcR agonists and another two as antagonists using a transgenic ecdysteroid reporter gene assay. The present results demonstrate that commercial C. arachnoidea extracts are rich in new, unusual bioactive ecdysteroids. Because of the lack of an authentic plant material, the truly biosynthetic or artifactual nature of these compounds cannot be confirmed.

Diversity-oriented synthesis through gamma radiolysis: Preparation of unusual ecdysteroid derivatives activating Akt and AMPK in skeletal muscle cells.

Gamma-ray radiation is a unique way to induce chemical transformations of bioactive compounds. In the present study, we pursued this approach to the diversity-oriented synthesis of analogs of 20-hydroxyecdysone (20E), an abundant ecdysteroid with a range of beneficial, non-hormonal bioactivities in mammals including humans. Gamma irradiations of aqueous solutions of 20E were conducted either in N2- or N2O-saturated solutions. Centrifugal partition chromatography was used to fractionate crude resulting irradiated materials using a biphasic solvent system composed of tert-butyl alcohol - ethyl acetate - water (0.45:0.9:1, v/v/v) in ascending mode. Subsequently, the products were purified by RP-HPLC. Fourteen ecdysteroids, including five new compounds, were isolated, and their structure were elucidated by 1D and 2D NMR and HRMS. Compounds 2-4, 7, 9, 12 and 15 were tested for their capacity to increase the Akt- and AMPK-phosphorylation of C2C12 murine skeletal myotubes in vitro. The compounds were similarly active on Akt as their parent compound. Stachysterone B (7) and a new ring-rearranged compound (12) were more potent than 20E in activating AMPK, indicating a stronger cytoprotective effect. Our results demonstrate the use of gamma irradiation in expanding the chemical diversity of ecdysteroids to obtain new, unusual bioactive metabolites.

Retinoid X receptor modulates vitellogenin gene expression in black tiger shrimp, Penaeus monodon.

Effective inducing of ovarian maturation in female shrimp broodstock is important for successful breeding programs. Vitellogenesis is a biochemical process during which a yolk protein precursor vitellogenin (Vg) is synthesized and thus, can be used to indicate ovarian maturation stage. In this study, transcriptional regulation of Vg synthesis in the black tiger shrimp, Penaeus monodon was investigated. Genome walking on 5' upstream sequence of Vg gene revealed several putative binding sites of lipophilic retinoic acid response elements (RARE), and nuclear hormone responsive elements. Deletion of RARE significantly reduced the promoter activity to drive the expression of luciferase reporter gene in Sf-9 cells. To validate the trans-factor that potentially controls Vg expression through RARE, a cDNA encoding retinoid X receptor (PmRXR), one of the RARE-bound transcription factors was cloned from P. monodon's ovary. PmRXR expression was detected in various shrimp tissues, and was up-regulated during ovary development in a similar way to Vg expression. The DNA-binding domain of PmRXR protein showed specific binding to RARE-containing region on Vg 5' upstream sequence as determined by Electrophoretic Mobility Shift Assay (EMSA). Furthermore, dsRNA-mediated PmRXR silencing in previtellogenic and vitellogenic shrimp revealed that suppression of PmRXR could reduce Vg transcript in both stages. Taken together, the results presented in this study indicate that RXR is possibly an activator protein that modulates Vg expression in shrimp ovary through the binding to RARE.

Ecdysteroids from the Aerial Parts of Paris verticillata.

Two new ecdysteroids 14-epi-polypodine B (1) and 22-oxo-hydroxyecdysterone (2), along with nine known compounds, polypodine B (3), viticosterone E (4), 20-hdroxyecdysone-2-acetate (5), 22-oxo-20-hydroxyecdysone (6), 5-hydroxyecdysone (7), pinnatasterone (8), 3-epi-20-hydroxyecdysone (9), ecdysterone (10) and stachysterone B (11), were isolated from the aerial parts of Paris verticillata. The structures of all compounds were elucidated by extensive spectroscopic analysis, quantum chemical calculations and ANN-PRA/DP4+ probability analysis. Among them, the absolute configuration of compound 1 and 2 was unambiguous determined by ECD. Also, the isolated compounds were assessed for their cytotoxic activities. Compounds 2, 3 and 7 exhibited significant cytotoxic activities against PC12, LN299 and SMCC7721 cells.

Naturally Occurring Ecdysteroids in Triticum aestivum L. and Evaluation of Fenarimol as a Potential Inhibitor of Their Biosynthesis in Plants.

Ecdysteroids (ECs) are steroid hormones originally found in the animal kingdom where they function as insect molting hormones. Interestingly, a relatively high number of these substances can also be formed in plant cells. Moreover, ECs have certain regulatory effects on plant physiology, but their role in plants still requires further study. One of the main aims of the present study was to verify a hypothesis that fenarimol, an inhibitor of the biosynthesis of ECs in the animal kingdom, also affects the content of endogenous ECs in plants using winter wheat Triticum aestivum L. as a model plant. The levels of endogenous ECs in winter wheat, including the estimation of their changes during a course of different temperature treatments, have been determined using a sensitive analytical method based on UHPLC-MS/MS. Under our experimental conditions, four substances of EC character were detected in the tissue of interest in amounts ranging from less than 1 to over 200 pg·g-1 FW: 20-hydroxyecdysone, polypodine B, turkesterone, and isovitexirone. Among them, turkesterone was observed to be the most abundant EC and accumulated mainly in the crowns and leaves of wheat. Importantly, the level of ECs was observed to be dependent on the age of the plants, as well as on growth conditions (especially temperature). Fenarimol, an inhibitor of a cytochrome P450 monooxygenase, was shown to significantly decrease the level of naturally occurring ECs in experimental plants, which may indicate its potential use in studies related to the biosynthesis and physiological function of these substances in plants.

Ecdysteroid Derivatives that Reverse P-Glycoprotein-Mediated Drug Resistance.

The expression of multidrug resistance P-glycoprotein (P-gp) by cancer cells represents one of the major drawbacks to successful cancer therapy. Accordingly, the development of drugs that inhibit the activity of this transporter remains a major challenge in cancer drug discovery. In this context, several new ecdysteroid derivatives have been synthesized and evaluated as P-gp inhibitors. Two of them (compounds 9 and 14) were able to resensitize CEMVbl100 and LoVoDoxo resistant cell lines to vinblastine and doxorubicin, respectively. Indeed, both compounds 9 and 14 increased the cellular accumulation of rhodamine 123 in cells expressing P-gp and stimulated basal P-glycoprotein-ATPase activity at a 1 µM concentration, demonstrating their interference with the transport of other substrates in a competitive mode. Moreover, in a medulloblastoma cell line (DAOY), compounds 9 and 14 reduced the side population representing cancer stem cells, which are characterized by a high expression of ABC drug transporters. Further, in DAOY cells, the same two compounds synergized with cisplatin and vincristine, two drugs used commonly in the therapy of medulloblastoma. Molecular docking studies on the homology-modeled structure of the human P-glycoprotein provided a rationale for the biological results, validating the binding mode within the receptor site, in accordance with lipophilicity data and observed structure-activity relationship information. Altogether, the present results endorse these derivatives as promising P-gp inhibitors, and they may serve as candidates to reverse drug resistance in cancer cells.

Side-chain cleaved phytoecdysteroid metabolites as activators of protein kinase B.

Phytoecdysteroids exert their non-hormonal anabolic and adaptogenic effects in mammals, including humans, through a partially revealed mechanism of action involving the activation of protein kinase B (Akt). We have recently found that poststerone, a side-chain cleaved in vivo metabolite of 20-hydroxyecdysone, exerts potent anabolic activity in rats. Here we report the semi-synthetic preparation of a series of side-chain cleaved ecdysteroids and their activity on the Akt phosphorylation in murine skeletal muscle cells. Twelve C-21 ecdysteroids including 8 new compounds were obtained through the oxidative side-chain cleavage of various phytoecdysteroids, or through the base-catalyzed autoxidation of poststerone. The complete 1H and 13C NMR spectroscopic assignments of the new compounds are presented. Among the tested compounds, 9 could activate Akt stronger than poststerone revealing that side-chain cleaved derivatives of phytoecdysteroids other than 20-hydroxyecdysone are valuable bioactive metabolites. Thus, our results suggest that the expectable in vivo formation of such compounds should contribute to the bioactivity of herbal preparations containing ecdysteroid mixtures.

Ecdysonelactones, Ecdysteroids from the Tropical Eastern Pacific Zoantharian Antipathozoanthus hickmani.

Despite a large occurrence, especially over the Pacific Ocean, the chemical diversity of marine invertebrates belonging to the order Zoantharia is largely underexplored. For the two species of the genus Antipathozoanthus no chemical study has been reported so far. The first chemical investigation of Antipathozoanthus hickmani collected at the Marine Protected Area "El Pelado", Santa Elena, Ecuador, led to the isolation of four new ecdysteroid derivatives named ecdysonelactones. The structures of ecdysonelactones A-D (1-4) were determined based on their spectroscopy data, including 1D and 2D NMR and HRMS. The four compounds of this family of ecdysteroids feature an unprecedented γ-lactone fused at the C-2/C-3 position of ring A. These derivatives exhibited neither antimicrobial nor cytotoxic activities.

New ecdysteroid and ecdysteroid glycosides from the roots of Serratula chinensis.

Three new ecdysteroid glycosides (1-3) and one new ecdysteroid (4), were isolated from the roots of Serratula chinensis. Their structures were established on the basis of extensive spectroscopic analysis and chemical methods.

Isolation and Purification of Three Ecdysteroids from the Stems of Diploclisia glaucescens by High-Speed Countercurrent Chromatography and Their Anti-Inflammatory Activities In Vitro.

High-speed counter-current chromatography was used to separate and purify ecdysteroids for the first time from the stems of Diploclisia glaucescens using a two-phase solvent system composed of ethyl acetate-n-butanol-ethanol-water (3:0.2:0.8:3, v/v). Three ecdysteroids were obtained from 260 mg of ethyl acetate extract of the residue obtained after evaporation of the crude ethanolicextractof D. glaucescens in one-step separation, which were identified as paristerone (I, 30.5 mg), ecdysterone (II, 7.2 mg), and capitasterone (III, 8.1 mg) by electrospray ionization mass spectrometry (ESI-MS) and nuclear magnetic resonance (NMR). Their anti-inflammatory activities were evaluated by measuring the inhibitory ratios of ß-glucuronidase release in rat polymorphonuclear leukocytes (PMNs) induced by platelet-activating factor. Compounds I-III showed significant anti-inflammatory activities with IC50-values ranging from 1.51 to 11.68 µM, respectively.

Backstabbing P-gp: Side-Chain Cleaved Ecdysteroid 2,3-Dioxolanes Hyper-Sensitize MDR Cancer Cells to Doxorubicin without Efflux Inhibition.

P-glycoprotein (P-gp, ABCB1) over-expression, causing a multi-drug resistant (MDR) phenotype, is a major problem in cancer chemotherapy that urgently requires novel approaches. Our previous studies showed certain ecdysteroid derivatives as promising chemo-sensitizers against MDR and non-MDR cancer cell lines while also exerting mild to moderate inhibition of P-gp function. Here we report the preparation of a set of substituted 2,3-dioxolane derivatives of poststerone, a known in vivo metabolite of 20-hydroxyecdysone (20E). In contrast with previously studied ecdysteroid dioxolanes, the majority of the new compounds did not inhibit the efflux function of P-gp. Nevertheless, a strong, dose dependent sensitization to doxorubicin was observed on a P-gp transfected cancer cell line and on its susceptible counterpart. We also observed that the MDR cell line was more sensitive to the compounds' effect than the non-MDR. Our results showed for the first time that the chemo-sensitizing activity of ecdysteroids can be fully independent of functional efflux pump inhibition, and suggest these compounds as favorable leads against MDR cancer.

Anti-Dengue Virus Constituents from Formosan Zoanthid Palythoa mutuki.

A new marine ecdysteroid with an α-hydroxy group attaching at C-4 instead of attaching at C-2 and C-3, named palythone A (1), together with eight known compounds (2-9) were obtained from the ethanolic extract of the Formosan zoanthid Palythoa mutuki. The structures of those compounds were mainly determined by NMR spectroscopic data analyses. The absolute configuration of 1 was further confirmed by comparing experimental and calculated circular dichroism (CD) spectra. Anti-dengue virus 2 activity and cytotoxicity of five isolated compounds were evaluated using virus infectious system and [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt (MTS) assays, respectively. As a result, peridinin (9) exhibited strong antiviral activity (IC50 = 4.50 ± 0.46 µg/mL), which is better than that of the positive control, 2'CMC. It is the first carotene-like substance possessing anti-dengue virus activity. In addition, the structural diversity and bioactivity of the isolates were compared by using a ChemGPS-NP computational analysis. The ChemGPS-NP data suggested natural products with anti-dengue virus activity locate closely in the chemical space.

Phytoecdysteroids and flavonoid glycosides among Chilean and commercial sources of Chenopodium quinoa: variation and correlation to physico-chemical characteristics.

BACKGROUND: Little is known about varietal differences in the content of bioactive phytoecdysteroids (PE) and flavonoid glycosides (FG) from quinoa (Chenopodium quinoa Willd.). The aim of this study was to determine the variation in PE and FG content among 17 distinct quinoa sources and identify correlations to genotypic (highland vs. lowland) and physico-chemical characteristics (seed color, 100-seed weight, protein content, oil content). RESULTS: PE and FG concentrations exhibited over four-fold differences across quinoa sources, ranging from 138 ± 11 µg g(-1) to 570 ± 124 µg g(-1) total PE content and 192 ± 24 µg g(-1) to 804 ± 91 µg g(-1) total FG content. Mean FG content was significantly higher in highland Chilean varieties (583.6 ± 148.9 µg g(-1)) versus lowland varieties (228.2 ± 63.1 µg g(-1)) grown under the same environmental conditions (P = 0.0046; t-test). Meanwhile, PE content was positively and significantly correlated with oil content across all quinoa sources (r = 0.707, P = 0.002; Pearson correlation). CONCLUSION: FG content may be genotypically regulated in quinoa. PE content may be increased via enhancement of oil content. These findings may open new avenues for the improvement and development of quinoa as a functional food.

Hormonal regulation and developmental role of Krüppel homolog 1, a repressor of metamorphosis, in the silkworm Bombyx mori.

Juvenile hormone (JH) has an ability to repress the precocious metamorphosis of insects during their larval development. Krüppel homolog 1 (Kr-h1) is an early JH-inducible gene that mediates this action of JH; however, the fine hormonal regulation of Kr-h1 and the molecular mechanism underlying its antimetamorphic effect are little understood. In this study, we attempted to elucidate the hormonal regulation and developmental role of Kr-h1. We found that the expression of Kr-h1 in the epidermis of penultimate-instar larvae of the silkworm Bombyx mori was induced by JH secreted by the corpora allata (CA), whereas the CA were not involved in the transient induction of Kr-h1 at the prepupal stage. Tissue culture experiments suggested that the transient peak of Kr-h1 at the prepupal stage is likely to be induced cooperatively by JH derived from gland(s) other than the CA and the prepupal surge of ecdysteroid, although involvement of unknown factor(s) could not be ruled out. To elucidate the developmental role of Kr-h1, we generated transgenic silkworms overexpressing Kr-h1. The transgenic silkworms grew normally until the spinning stage, but their development was arrested at the prepupal stage. The transgenic silkworms from which the CA were removed in the penultimate instar did not undergo precocious pupation or larval-larval molt but fell into prepupal arrest. This result demonstrated that Kr-h1 is indeed involved in the repression of metamorphosis but that Kr-h1 alone is incapable of implementing normal larval molt. Moreover, the expression profiles and hormonal responses of early ecdysone-inducible genes (E74, E75, and Broad) in transgenic silkworms suggested that Kr-h1 is not involved in the JH-dependent modulation of these genes, which is associated with the control of metamorphosis.

Assessing herbal products with health claims.

Herbs, herbal extracts, or phytochemicals are broadly used as foods, drugs, and as traditional medicines. These are well regulated in Europe, with thorough controls on both safety and efficacy or validity of health claims. However, the distinction between medicines and foods with health claims is not always clear. In addition, there are several cases of herbal products that claim benefits that are not scientifically demonstrated. This review details the European Union (EU) legislative framework that regulates the approval and marketing of herbal products bearing health claims as well as the scientific evidence that is needed to support such claims. To illustrate the latter, we focus on phytoecdysteroid (PE)-containing preparations, generally sold to sportsmen and bodybuilders. We review the limited published scientific evidence that supports claims for these products in humans. In addition, we model the in silico binding between different PEs and human nuclear receptors and discuss the implications of these putative bindings in terms of the mechanism of action of this family of compounds. We call for additional research to validate the safety and health-promoting properties of PEs and other herbal compounds, for the benefit of all consumers.

The minor ecdysteroids from Ajuga turkestanica.

INTRODUCTION: Ajuga turkestanica is a plant used in traditional medicine for its high ecdysteroid content, including the presence of the particularly active turkesterone, which possess efficient anabolic activity. OBJECTIVES: To isolate and identify minor ecdysteroids present in a semi-purified plant fraction containing ca. 70% turkesterone. MATERIAL AND METHODS: Multi-step preparative HPLC (combining RP- and NP-HPLC systems) was used to purify the different components present in the turkesterone fraction. Isolated compounds were identified by high-resolution mass spectrometry and 2D-NMR. RESULTS: Fourteen ecdysteroids (including turkesterone and 20-hydroxyecdysone) were isolated. Seven of these, all bearing an 11α-hydroxy group, were previously unreported. CONCLUSION: Ajuga turkestanica ecdysteroids are characterised by the abundance of 11α-hydroxylated compounds and by the simultaneous presence of 24C, 27C, 28C and 29C ecdysteroids. It is expected that even more ecdysteroids are to be found in this plant since the starting material for this study lacked the less polar ecdysteroids. The simultaneous presence of 20-hydroxyecdysone and turkesterone (its 11α-hydroxy analogue) as the two major ecdysteroids suggests that every ecdysteroid is probably present in both 11α-hydroxy and 11-deoxy forms.

[Phytoecdysteroids influence on the hormonal status and apoptosis in growing rats].

The impact of the 15-day consumption of Serratula coronata extract containing phytoecdysteroids on some indicators of hormonal status and activity of apoptosis in various organs of growing male Wistar rats (initial body weight 127.8 +/-2.5 sigma) has been studied. The extract from the leaves of Serratula coronata was added to the water of animals of experimental groups 2 and 3 (n = 8 in each group) daily at the dose of 5 and 15 mg phytoecdysteroids per kg of body weight respectively. Animals of the control group 1 (n = 8) received water alone throughout the experiment. Daily volume of drunk fluid was recorded. At the 15th day of the experiment animals were taken out using the decapitation under the light ether anesthesia. The content of corticosterone, prostaglandin E2 and beta-endorphin in rat blood plasma were determined by ELISA test. Plasma level of noradrenaline was determined by HPLC. DNA damage and percentage of apoptotic cells (apoptotic index) were measured in isolated cells of the thymus, heart and brain by single-cell gel electrophoresis (the comet assay). Significantly lower concentration of norepinephrine was detected in plasma of experimental animals from groups 2 and 3 (10.3 +/- 1.1 and 7.2 +/- 0.8 ng/ml, respectively) compared to the same index in the control group (20.4 +/- 3.4 ng/ml). Significant differences of other biochemical parameters for all groups of animals have not been identified. Statistical significant difference in the ratio of corticosterone/norepinephrine compared with control animals was detected for a group of rats consumed the highest dose of phytoecdysteroids. There was no statistically significant difference in DNA fragmentation and apoptosis index in animals consumed phytoecdysteroids in compare with the control group of animals. The absence of the activity of apoptosis in cells of the heart, brain and thymus of rats treated with phytoecdysteroid extract may indicate the safety of its use in the diet of the animals.