Diterpene Alkaloids Research Articles

Study on change rule of 6 ester-type alkaloids in process of Heishunpian

To study the variation of six ester-type alkaloids and characteristic fingerprints in the process from Radix Aconite Lateralis to Heishunpian and lay a foundation for the study of the processing principle of Heishunpian, HPLC. analysis was performed on a Phenomenex Gemini C18 (4.6 mm x 250 mm, 5 microm) with acetonitrile and 40 mmol x L(-1) ammonium acetate (adjusted to pH 10 with concentrated ammonia water) as mobile phase. The detection wavelength was set at 235 nm. The flow rate was set at 0.8 mL x min(-1) and the injection volume was 10-20 microL. Six ester-type alkaloids were determined and characteristic fingerprints of the process were established. As the process continues, the contents of diester diterpene alkaloids were decreased step by step, while the contents varia tion of monoester diterpene alkaloids were not obvious. Each sample showed significant difference in characteristic fingerprints. With the exception of 6 known monoester diterpene alkaloids and diester diterpene alkaloids, 13 peaks were marked in the characteristic fingerprints, of which the total change rule of the other 7 unknown peaks were similar with 3 diester diterpene alkaloids. The established method is accurate, reliable and repeatable, and can provide reference for revealing change rule of index components and illuminating processing principle in the process of Heishunpian.

Mechanisms of psychopharmacological effects of alkaloid Z77 under conditions of brain ischemia.

We studied the psychopharmacological effects of atisine-type diterpene alkaloid Z77 in a rat model of brain ischemia in the morning and at night. The type of developing locomotor disorders in animals was shown to depend on circadian rhythms. Administration of Z77 substantially corrected manifestations of psychoneurological symptoms. The parameters of orientation and exploratory behavior and conditioned reflex activity were normalized. The key role of receptors of neural stem cells to fibroblast growth factor in the realization of their growth potential under the influence of the alkaloid was demonstrated. Under in vitro conditions, antibodies to fibroblast growth factor receptor abolished the increase in the number of neural CFU caused by Z77 in the culture of intact cells from the paraventricular region of the brain.

Diterpene alkaloids with an aza-ent-kaurane skeleton from Isodon rubescens.

Two compounds belonging to a new group of diterpene alkaloids, kaurines A and B (1 and 2), and an alkaloid bearing a succinimide moiety (3) were obtained from Isodon rubescens. Their structures and absolute configurations were determined by spectroscopy and quantum-chemical computational (13)C NMR and ECD data analysis. These alkaloids differ from known diterpene alkaloids and diterpenoids and are presumably biosynthesized from ent-kaurane diterpenoids.

Asymmetric Total Synthesis of the Indole Diterpene Alkaloid Paspaline

Asymmetric Total Synthesis of the Indole Diterpene Alkaloid Paspaline

Cerebroprotective and regenerative effects of alkaloid Z77 under conditions of brain ischemia.

We studied the psychopharmacological effects of atisine-type diterpene alkaloid Z77 in a rat model of cerebral ischemia. Pronounced cerebroprotective effect was found consisting in normalization of the orienting and exploratory activity and conditioned behavior associated with significant correction of morphological changes in the brain. The direct stimulatory effect of Z77 on neural stem cells was shown in vitro.

ChemInform Abstract: Modification of Biologically Active Plant Metabolites via the Transition Metal Catalyzed Reactions

AbstractReview: 44 refs.

Analgesic activity of diterpene alkaloids from Aconitum baikalensis.

We compared analgesic activities of individual alkaloids extracted from Baikal aconite (Aconitum baikalensis): napelline, hypaconitine, songorine, mesaconitine, 12-epinapelline N-oxide. The detected analgesic activity was comparable to that of sodium metamizole. The mechanisms of analgesia were different in diterpene alkaloids of different structure. The antinociceptive effect of atisine alkaloids (12-epinapelline N-oxide, songorine) was naloxonedependent and realized via opioid receptor modulation.

ChemInform Abstract: Indole Diterpene Alkaloids as Novel Inhibitors of the Wnt/β‐Catenin Pathway in Breast Cancer Cells.

AbstractNine new penitrem analogs (Ia)‐(Ig), (IIa), and (IIb) are semisynthetically prepared in an attempt to identify pharmacophores correlated with BK channel inhibition and tremorgenicity of penitrems and decrease their toxicity.

Antimalarial diterpene alkaloids from the seeds of Caesalpinia minax

Two new diterpene alkaloids, caesalminines A (1) and B (2), possessing a tetracyclic cassane-type furanoditerpenoid skeleton with γ-lactam ring, were isolated from the seeds of Caesalpinia minax. Their structures were determined by different spectroscopic methods and ECD calculation. The plausible biosynthetic pathway of caesalminines A and B was proposed. The anti-malarial activity of compounds 1 and 2 is presented with IC50 values of 0.42 and 0.79μM, respectively.

Anti-inflammatory activity of diterpene alkaloids from Aconitum baikalense.

We compared anti-inflammatory activity of individual diterpene alkaloids isolated from Aconitum baikalense (napelline, songorine, hypaconitine, mesaconitine, 12-epinapelline N-oxide) under conditions of acute inflammation of different genesis. The tested substances showed high antiexudative activity comparable with that of sodium diclofenac. Unlike nonsteroidal anti-inflammatory drugs, diterpene alkaloids exerted no ulcerogenic effect.

Diterpene Alkaloids from the Roots of Aconitum moldavicum and Assessment of Nav 1.2 Sodium Channel Activity of Aconitum Alkaloids

A new aconitane alkaloid, 1-O-demethylswatinine (1), was isolated from the root of Aconitum moldavicum together with the known compounds cammaconine (2), columbianine (3), swatinine (4), gigactonine (5), delcosine (6), lycoctonine (7), and ajacine (8). The structures were established by means of HRESIMS, 1D and 2D NMR spectroscopy, including 1H-1H COSY, NOESY, HSQC, and HMBC experiments, resulting in complete 1H-NMR chemical shift assignments for 1-4. The effects of the isolated compounds 4-8, together with eighteen other Aconitum diterpene and norditerpene alkaloids with different skeletal types and substitution patterns, were studied on Nav 1.2 channels by the whole-cell patch clamp technique, using the QPatch-16 automated patch clamp system. Pyroaconitine, ajacine, septentriodine, and delectinine demonstrated significant Nav 1.2 channel inhibition (57-42 %) at 10 µM concentration; several other compounds (acovulparine, acotoxicine, hetisinone, 14-benzoylaconine-8-O-palmitate, aconitine, and lycoctonine) exerted moderate inhibitory activity (30-22 %), while the rest of the tested alkaloids were considered to be inactive. On the basis of these results and by exhaustive comparison of data of previously published computerized QSAR studies on diterpene alkaloids, certain conclusions on the structure-activity relationships of Aconitum alkaloids concerning Nav 1.2 channel inhibitory activity are proposed.

Direct and comprehensive analysis of ginsenosides and diterpene alkaloids in Shenfu injection by combinatory liquid chromatography–mass spectrometric techniques

Shenfu injection (SFI) is a widely used Chinese herbal formulation for cardiac diseases prepared from red ginseng and processed aconite root. Clinical observations and pharmacological effects on SFI have been well investigated. Chemical analysis and quality control studies of this formulation, however, are relatively limited, especially regarding toxic aconite alkaloids. In this work, a high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (HPLC–QTOF MS) method was applied to comprehensive analysis of constituents in SFI. Highly sensitive MS allows direct analysis of injections without additional sample pretreatment required. Using diagnostic ions and fragmentation rules, we identified 23 trace diterpene alkaloids, nineteen ginseng saponins, one panaxytriol, and one 5-hydroxymethylfurfural in SFI. A LC–MS method with selected ion monitoring was then used to quantify 24 major alkaloids and ginsenosides. The method was validated in terms of linearity, accuracy and precision. Especially, the limits of quantification were low to 0.4–18ng/mL for diterpene alkaloids. The total concentrations of saponins and alkaloids were about 676–742μg/mL and 3–7μg/mL in five batches of SFI samples, respectively. Finally, cosine ratio and euclidean distance were introduced to evaluate the batch-to-batch reproducibility of SFI samples, and the results demonstrated high quality consistency. Global identification and quantification of complex constituents based on LC–MS promises wide applications in quality control and batch monitoring for herbal products.

Cassaine diterpene alkaloids from Erythrophleum fordii and their anti-angiogenic effect

Angiogenesis plays a critical role in embryonic development and various physiological processes. However, excessive angiogenesis is associated with several pathological conditions including cancer. Angiogenesis is closely related to tumor growth, invasion and metastasis, and is considered a prime target for anticancer therapy. In this study, two new mono cassaine diterpenoid amides (1, 5) and four known compounds (2–4, 6) were isolated from the bark of Erythrophleum fordii (Leguminosae). Their chemical structures were established mainly by 1D and 2D NMR techniques and mass spectrometry. The effects of isolates on endothelial tube formation on Matrigel were investigated. Among them, compound 3 was found to have the most potent inhibitory effect on the capillary-like structure formation of human umbilical vein endothelial cells (HUVECs).

Identification of the Target Protein of Agelasine D, a Marine Sponge Diterpene Alkaloid, as an Anti‐dormant Mycobacterial Substance

One of the major reasons for the wide epidemicity of tuberculosis and for the necessity for extensive chemotherapeutic regimens is that the causative agent, Mycobacterium tuberculosis, has an ability to become dormant. Therefore, new lead compounds that are anti-bacterial against M. tuberculosis in both active and dormant states are urgently needed. Marine sponge diterpene alkaloids, agelasines B, C, and D, from an Indonesian marine sponge of the genus Agelas were rediscovered as anti-dormant-mycobacterial substances. Based on the concept that the transformants over-expressing targets of antimicrobial substances confer drug resistance, strains resistant to agelasine D were screened from Mycobacterium smegmatis transformed with a genomic DNA library of Mycobacterium bovis BCG. Sequence analysis of the cosmids isolated from resistant transformants revealed that the responsible gene was located in the genome region between 3475.051 and 3502.901 kb. Further analysis of the transformants over-expressing the individual gene contained in this region indicated that BCG3185c (possibly a dioxygenase) might be a target of the molecule. Moreover, agelasine D was found to bind directly to recombinant BCG3185c protein (KD 2.42 μm), based on surface plasmon resonance (SPR). This evidence strongly suggests that the BCG3185c protein is the major target of agelasine D, and that the latter is the anti-mycobacterial substance against dormant bacilli.

Indole diterpene alkaloids as novel inhibitors of the Wnt/β-catenin pathway in breast cancer cells

Penitrems are indole diterpene alkaloids best known for their BK channel inhibition and tremorgenic effects in mammals. In a previous study, penitrems A–F (1–5), their biosynthetic precursors, paspaline (6) and emindole SB (7), and two brominated penitrem analogs 8 and 9 demonstrated promising in vitro antiproliferative, antimigratory, and anti-invasive effects in the MTT (MCF-7 and MDA-MB-231), wound-healing, and Cultrex® BME cell invasion (MDA-MB-231) assays, respectively. The study herein reports the novel ability of penitrem A to suppress total β-catenin levels in MDA-MB-231 mammary cancer cells. Nine new penitrem analogs (10–18) were semisynthetically prepared, in an attempt to identify pharmacophores correlated with BK channel inhibition and tremorgenicity of penitrems and decrease their toxicity. The degree of BK channel inhibition was assessed using the nematode Caenorhabditis elegans, and in vivo tremorgenic EC50 was calculated using CD-1 male mice following an Up-and-Down Procedure (UDP). Although new analogs were generally less active than parent compound 1, some showed no BK channel inhibition or tremorgenicity and retained the ability of penitrem A (1) to suppress total β-catenin levels in MDA-MB-231 cells. Paspaline (6) and emindole SB (7), both lacking BK channel inhibition and tremorgenicity, represent the simplest indole diterpene skeleton that retains the antiproliferative, antimigratory and total β-catenin suppressing effects shown by the more complex penitrem A (1).

Assessment of the Nav1.2 sodium channel activity of Aconitum diterpene and norditerpene alkaloids

Voltage-gated sodium channels in sensory neurons have been found to play a crucial role in several chronic painful neuropathies of different aethiology. Pharmacons that exhibit a use-dependent blockade of these channels, like anticonvulsants, antiarrhythmics and local anesthetics, have been proven to be useful drugs in the treatment of chronic neuropathic or inflammatory pain states, epilepsy, migraine and neurodegeneration related to ischaemia.

A novel concept for detoxification: Complexation between aconitine and liquiritin in a Chinese herbal formula (‘Sini Tang’)

Ethnopharmacological relevanceSini Tang (SNT, ▪) is a traditional Chinese herbal formulation consisting of three different herbs: Aconitum carmichaelii (Fuzi, ▪), Zingiber officinale (Ganjiang, ▪), and Glycyrrhiza uralensis (Gancao, ▪). For this study, we modified this mixture by adding the bark of Cinnamomum cassia (Rougui, ▪). Aconitum carmichaelii contains aconitine and its derivatives, all of which are highly toxic alkaloids. These compounds are commonly detoxified with pyrolytic and hydrolytic pretreatments, such as Heishunpian (▪), which requires repeated soaking in salt water, boiling until the roots turn black, and drying in the oven. We now demonstrate that Glycyrrhiza uralensis, which is often used in Traditional Chinese Medicine for detoxification, reduces the concentration of free aconitine in decoctions by forming a complex between liquiritin and aconitine. Materials and methodsAqueous extracts of SNT, each individual herb or herbal mixture, and methanolic extracts of individual herbs were tested for free aconitine by HPLC coupled with a diode array detector. A detected complex was investigated by NMR and UV/vis spectroscopy. The continuous variations method and 1H-NMR titrations provided the complex stoichiometry and binding constant. A 2D-ROESY experiment was performed to obtain the structural details of the formed complex. ResultsA fast and simple HPLC method was developed to determine the amounts of aconitine and its derivatives found in herbal extracts. The Heishunpian pretreatment led to nearly complete pyrolysis and hydrolysis of the toxic compounds. However, in some batches, considerable amounts of aconitine remained. The addition of Glycyrrhiza uralensis to Aconitum carmichaelii, or liquiritin to free aconitine, led to a complexation with aconitine. The complex possessed a 1:1 stoichiometry and a binding constant of ca. 3000L/mol to 4000L/mol in mixtures of aqueous methanol. ConclusionsA new HPLC based method allows the concentration of toxic aconitine and other diester diterpene alkaloids in herbal extracts to be rapidly determined. This method provides a starting point for the development of routine quality control procedures. The complexation of free aconitine by adding an excess of Glycyrrhiza uralensis or free liquiritin to SNT formulations will make these formulations safer.

Identification of diterpene alkaloids from Aconitum napellus subsp. firmum and GIRK channel activities of some Aconitum alkaloids

Diterpene alkaloids neoline (1), napelline (2), isotalatizidine (3), karakoline (4), senbusine A (5), senbusine C (6), aconitine (7) and taurenine (8) were identified from Aconitum napellus L. subsp. firmum, four (2–4, 6) of which are reported for the first time from this plant. The structures were determined by means of LC–MS, 1D and 2D NMR spectroscopy, including 1H–1H COSY, NOESY, HSQC and HMBC experiments. Electrophysiological effects of the isolated compounds, together with nine diterpene alkaloids previously obtained from Aconitum toxicum and Consolida orientalis were investigated on stable transfected HEK–hERG (Kv11.1) and HEK–GIRK1/4 (Kir3.1 and Kir3.4) cell lines using automated patch clamp equipment. Significant blocking activity on GIRK channel was exerted by aconitine (7) (45% at 10μM), but no blocking activities of the other investigated compounds were detected. The tested compounds were inactive on hERG channel in the tested concentration.The comparison of the previously reported metabolites of A. napellus subsp. firmum and compounds identified in our experiment reveals substantial variability of the alkaloid profile of this taxon.

Mechanisms of Hemostimulating Effect of Aconitum baicalense Diterpene Alkaloids

A mixture of diterpene alkaloids of Aconitum baicalense exhibited pronounced regenerative hemostimulating properties on the model of cytostatic myelosuppression. The therapeutic effect is based on activation of hemopoietic progenitor cells against the background of increased feeder capacity of stromal compartment of the hemopoiesis-inducing microenvironment and decreased count of mesenchymal stem cells in the bone marrow.

Modification of Biologically Active Plant Metabolites Via the Transition Metal Catalyzed Reactions

Developed by the author’s research laboratory methods of functionalization of some plant metabolites or their derivatives, viz., the eudesmane-type methylenelactones, diterpene and morphinane alkaloids, furanolabdanoids, and coumarins, using the transition metal catalyzed reactions, are reviewed. The activity<br />of linear methylene lactone of the eudesmane type in the Heck reaction are analyzed. It is shown that the outcome of the Heck reaction is significantly influenced by the structure of methylidenelactone. The Pd-catalyzed arylation of isoalantolactone with arylhalogenides or 6-bromodeoxyvasicinone occurred with<br />formation mainly of cross-coupling products with the (E) - configuration of the double bond. Synthesis of halogen derivatives of lappaconitine, tetrahydrothebaine and dihydrothebaine-hydroquinone and investigation of in the Heck or Sonogashira reactions gave the possibility for obtaining of new alkaloid derivatives with additional substituents in the aromatic rings. Homocoupling reaction or Sonogashira crosscoupling reaction of 5´- ethynyllappaconitine are used for synthesis of dimeric alkaloids of aconitane types. Pd-catalyzed amination of 2-(1,3-dibromoprop-2-ylidene)oreoselone and the transformations of oreoselone triflate, upon the action of palladium compounds allowed us to accomplish new modifications of linear furocoumarins. The method of enyne cycloisomerization of <em>ω</em>-alkynylfurans catalyzed with Au(III) was successfully obtained in the transformations of furanolabdanoids. The copper(I) salts catalyzed 1,3-dipolar cycloaddition reaction of azides to terminal alkynes belongs to the group of click-reactions was used in the synthesis of macrocyclic structures of labdane diterpenoids. The copper-catalyzed 1,3-dipolar cycloaddition reaction of 2 - azidooreoselone with various alkynes yielded diverse 2-(1,2,3-triazolyl)furocoumarins. The advantages of transition metal catalyzed reactions to the transformations of plant metabolites and its derivatives shown the possibility of introduction of several bioisosteric groups, and other fragments providing additional interactions and selectivity of binding with receptors and enzymes.