Autophagy protects against neural cell death induced by piperidine alkaloids present in Prosopis juliflora (Mesquite)

ABSTRACT Prosopis juliflora is a shrub that has been used to feed animals and humans. However, a synergistic action of piperidine alkaloids has been suggested to be responsible for neurotoxic damage observed in animals. We investigated the involvement of programmed cell death (PCD) and autophagy on the mechanism of cell death induced by a total extract (TAE) of alkaloids and fraction (F32) from P. juliflora leaves composed majoritary of juliprosopine in a model of neuron/glial cell co-culture. We saw that TAE (30 µg/mL) and F32 (7.5 µg/mL) induced reduction in ATP levels and changes in mitochondrial membrane potential at 12 h exposure. Moreover, TAE and F32 induced caspase-9 activation, nuclear condensation and neuronal death at 16 h exposure. After 4 h, they induced autophagy characterized by decreases of P62 protein level, increase of LC3II expression and increase in number of GFP-LC3 cells. Interestingly, we demonstrated that inhibition of autophagy by bafilomycin and vinblastine increased the cell death induced by TAE and autophagy induced by serum deprivation and rapamycin reduced cell death induced by F32 at 24 h. These results indicate that the mechanism neural cell death induced by these alkaloids involves PCD via caspase-9 activation and autophagy, which seems to be an important protective mechanism.

Pseudoxandra sclerocarpa maas, colombian medicinal plant: a review / Pseudoxandra sclerocarpa maas, planta medicinal colombiana: una revisión

The Annonaceae family is one of the largest, with 130 genre and 2500 species, consisting of trees, shrubs and a few vines. Within this family, the Pseudoxandra genus of neotropical distribution is found. In Colombia, there are endemic and native species, distributed in the Amazon region and along the valley of the Magdalena River in the Chocó. Of the total of 22 species that form the genus in Colombia, Pseudoxandra sclerocarpa Maas is exclusive of the Antioquia region, receiving the common name of garrapato or frisolo. From this tree, bisbenzylisoquinolinic alkaloids like antioquine, medellline, obaberine, among others, has been isolated. Also neolignans: dieugenol and dehydro-1-O-methydehydrodieugenol. It is used in traditional medicine as an antiparasitic. From the pharmacological point of view, the alkaloids have shown activity against leishmaniasis and also have spasmolytic activity. Within the bisbenzylisoquinolinic alkaloids, antioquine has properties of being calcium antagonist.

La familia Annonaceae es uno de los más grandes, con 130 géneros y 2.500 especies, que consiste en árboles, arbustos y algunos bejucos. Dentro de esta familia, el género Pseudoxandra es de distribución neotropical. En Colombia existen especies endémicas y nativas, distribuidas en la región del Amazonas ya lo largo del valle del río Magdalena en el Chocó. Del total de 22 especies que forman el género en Colombia, Pseudoxandra sclerocarpa es exclusiva de la región de Antioquia, recibiendo el nombre común de garrapato o frisolo. De este árbol se ha aislado alcaloides bisbencilisoquinolínicos como antioquina, medelllina, obaberina, entre otros. También neolignanos: dieugenol y dehidro-1-O-metil-dehidrodieugenol. Se utiliza en la medicina tradicional como un antiparasitario. Desde el punto de vista farmacológico, los alcaloides han mostrado actividad contra la leishmaniasis y también tienen actividad espasmolítica. Dentro de los alcaloides bisbencilisoquinolínicos, antioquina tiene propiedades de ser antagonista del calcio.

Haplophytin B from Maclurodendron porteri

An alkaloid from Maclurodendron porteri has been isolated and characterized. Extraction process was conducted by acid-base extraction method followed by column chromatography. The structure was established by nuclear magnetic resonance spectroscopy and mass spectrometry. The compound was identified as haplophytin B which occurs commonly in the Rutaceae family. However, this is the first time this alkaloid was isolated and reported from the species. The compound showed no inhibition against Staphylococus aureus, Pseudomonas aeruginosa, Bacillus cereus and Escherichia coli and no cytotoxic activity against H199 and A549 cell lines.

Withanolid amine and nicotine from Dunalia spinosa (Solanaceae) / Amino-witanólido y nicotina de Dunalia spinosa (Solanaceae)

A new withanolid amine was isolated from Dunalia spinosa (Solanaceae). Its relative stereochemistry was determined using FT-IR, 1H and 13C NMR spectroscopies and high resolution mass spectrometry. Nicotine was also isolated; chemotaxonomic and archaeological implications are discussed.

Un nuevo amino-witanólido fue aislado de Dunalia spinosa (Solanaceae). Su estereoquímica relativa fue determinada usando espectroscopías FT-IR y RMN de 1H y 13C, y espectrometría de masas de alta resolución. También fue aislada nicotina; se discuten las implicancias quimotaxonómicas y arqueológicas.

Chemical constituents from Zanthoxylum setulosum (Rutaceae) / Costituyentes químicos de Zanthoxylum setulosum (Rutaceae)

Following our phytochemical studies of Costa Rican plants, in this work we report the isolation and identification of eight compounds from aerial parts of Zanthoxylum setulosum (Rutaceae). They were identified as the alkaloid skimmianine, the lignans savinin, kusunokinin, sesamin, syringaresinol and the isopentenyl ether of pluviatol, the amide aurantiamide acetate, and the triterpen lupeol. This is the first report of isolation of skimmianine from the leaves of Z. setulosum and its presence confirm that quinoline and benzophenanthridine alkaloids, can be considered as chemotaxonomic markers of this genus. All the isolated compounds were characterized by spectroscopic methods (including 1H-NMR, 13C-NMR, , HMQC, HMBC and NOESY) and comparison with the literature data.

Continuando con el estudio fitoquímico de plantas de Costa Rica, en este trabajo informamos el aislamiento e identificación de ocho compuestos de las partes aéreas de Zanthoxylum setulosum (Rutaceae). Los compuestos fueron identificados como el alcaloide skimmianina, los lignanos savinina, kusunokinina, sesamina, siringaresinol y el éter isopentílico del pluviatol, la amida conocida como acetato de aurantiamida, y el triterpeno lupeol. Este es el primer informe del aislamiento de skimmianina en las hojas de Z. setulosum, lo cual confirma que alcaloides quinolínicos y benzofenantridinicos pueden ser considerados marcadores quimiotaxonómicos en éste género. La estructura de los compuestos aislados fue caracterizada por métodos espectroscópicos (incluyendo 1HNMR, 13C-NMR, HMQC, HMBC y NOESY) y comparación con datos de la literatura.

Examination of camptothecin and 10-hydroxycamptothecin in Camptotheca acuminata plant and cell culture, and the affected yields under several cell culture treatments

Camptothecin and its derivatives are monoterpenoid indole alkaloids exhibiting significant anti-tumor actions. With the aim of improving the production of these pharmaceuticals, the contents of camptothecin and 10-hydroxycamptothecin in different tissues including roots, stems, leaves, young flower buds, opening flowers, fading flowers and seeds from Camptotheca acuminata, were investigated. The young flower buds had the highest alkaloid concentrations (camptothecin, 2.46 mg/g of dry weight; 10-hydroxycamptothecin, 1.41 mg/g of dry weight). Callus showed lower concentrations but it should also be considered as a potential source of these pharmaceuticals. In the present study, the growth rate of Camptotheca acuminata cells in culture did not correlate with contents of camptothecin and 10-hydroxycamptothecin. Alkalo id accumulation by cells under various treatments (heavy metal ions, UV-B), methyl-jasmonate, abscisic acid, salicylic acid and hydrogen peroxide was examined, and the most notable effects appeared in the cells induced by UV-B light (which showed an 11-fold increase in camptothecin concentration) and by salicylic acid (which showed a 25-fold increase in 10-hydroxycamptothecin concentration). These results are significant in the context of the production of both pharmaceuticals.

Cardiac cellular actions of quebrachidine, an indole alkaloid isolated from Rauwolfia viridis Roem et Schult

INTRODUCTION: the search for new drugs with safer therapeutic profiles in Cardiology is still a need and natural products, particularly from plants, constitute an excellent source of new compounds. OBJECTIVE: to study the cardiac cellular actions of quebrachidine an indole alkaloid, extracted from the roots of Rauwolfia viridis R et S, known as Quebrachidine, which is structurally related to the antiarrhythmics ajmaline and prajmaline. METHODS: several complementary experimental approaches to evaluate the effects of quebrachidine on the electrophysiological and contractile properties of cardiac tissues and cells were used. RESULTS: quebrachidine increased the ventricular fibrillation threshold in anaesthetized rabbits. It decreased the maximum rate of depolarization and increased the duration of the ventricular action potential in different species. These actions were accompanied by a positive inotropic effect over a broad concentration range and were consistent with the increase in Ca2+ currents recorded in single ventricular cardiomyocytes. CONCLUSIONS: the present results demonstrate that quebrachidine keeps the antiarrhythmic profile of ajmaline and prajmaline but also demonstrates a net positive inotropic action on cardiac tissues predictive of better therapeutic safety margin. Our results suggest that ajmalan-like molecular structures could provide a sound basis for the search of effective antiarrhythmics with positive inotropic effect

INTRODUCCIÓN: la búsqueda de nuevos fármacos con perfiles terapéuticos más seguros en cardiología, es aun una necesidad y los productos naturales, particularmente de plantas, constituyen una fuente excelente de nuevos compuestos. OBJETIVOS: estudiar las acciones celulares cardíacas de la quebrachidina, un alcaloide indólico extraído de las raíces de Rauwolfia viridis R et S, el cual está estructuralmente relacionado con los antiarrítmicos ajmalina y prajmalina. MÉTODOS: se utilizaron diferentes modelos experimentales complementarios para evaluar los efectos de la quebrachidina sobre las propiedades electrofisiológicas y contráctiles de tejidos y células cardíacas. RESULTADOS: la quebrachidina incrementó el umbral para la fibrilación ventricular en conejos anestesiados. Este alcaloide redujo la velocidad máxima de despolarización y aumentó la duración del potencial de acción ventricular de diferentes especies. Estas acciones estuvieron acompañadas de un efecto inotrópico positivo en un amplio rango de concentraciones y asociadas a un incremento en las corrientes de Ca2+ en cardiomiocitos ventriculares aislados. CONCLUSIONES: estos resultados demuestran que la quebrachidina conserva el perfil antiarrítmico de la ajmalina y la prajmalina pero muestra un efecto inotrópico positivo neto en tejidos cardíacos lo cual predice un mejor margen de seguridad terapéutico. Los resultados sugieren que las estructuras moleculares con núcleo ajmalano pueden constituir una base firme para la búsqueda de antiarrítmicos con efecto inotrópico positivo

Preliminary phytochemical screening of some plants of ethnobotanical importance from district Gilgit of Northern Areas, Pakistan

Seven medicinal plants of ethnobotanical importance belonging to families Elaeganaceae, Gentianaceae, Cupressaceae, Asleraceae, Tamaricaceae, Berberidaceae and Salicaceae were investigated for the presence of alkaloids, amino acids, anthraquinone [free nad as glycosides] ascorbic acid, carbohydrates, coumarins, flavonoids, phenolics, proteins, saponins and steroids in their coumarins, phenolics and proteins. Ephedra gerardiana [stem] [family ephedraceae] tested positive for alkaloids, ascorbic acid, coumarins, phenolics, proteins, saponins and steroids. Tamarix gallica [Family Tamaricaceae] tested positive for alkaloids, amino acids, anthraquinone as glycoside, ascorbic acid, carbohydrates, flavonoids, phenolics, proteins and steroids in stems, roots and leaves. Salix accomophylla [family Silaceae] showed positive results for alkaloids, amino acids, anthraquinone [free and as glycosides] ascorbic acid, carbohydrates, flavonoids, phenolics, proteins, saponins and steroids. Hippophe rhamnoides [family Elaeganaceae] showed positive results for alkaloids, amino acids, anthraquinone [free and as glycosides] ascorbic acid, carbohydrates, coumarins, flavonoids, phenolics, proteins, saponins and steroids. Berberis aristata [family Berberidaceae] showed positive results for alkaloids, amino acids, ascorbic acid, carbohydrates, flavonoids, phenolics, proteins and steroids in stem, roots and leaves, Juniperus excelsa [Family Juniperaceae] showed positive results for anthraquinone [both free and as glycosides], carbohydrates, phenolics, proteins, saponins and steroids

Plant-derived antimalarial agents: new leads and efficient phythomedicines: part 1: Alkaloids

Malaria remains one of the most serious world health problem and the major cause of mortality and morbidity in the endemic regions. Brazil is among the 30 high-burden countries and most of the cases occur in the Legal Amazonian Region. New chemotherapeutical agents are needed for the treatment of malaria. Many plant species are used in traditional medicines of malarious countries and a relatively few number of these have been investigated for evaluation of their antimalarial effect. Still lower is the number of those that have had the active natural compounds isolated and the toxicity determined. This area is, then, of great research interest. discovery project of antimalarial natural products from plants traditionally used to treat malaria must include in vitro and in vivo assays as well as bioguided isolation of active compounds. The final products would be antimalarial chemical entities, potential new drugs or templates for new drugs development, and/or standardized antimalarial extracts which are required for pre-clinical and clinical studies when the aim is the development of effective and safe phythomedicines. This review discusses these two approaches, presents briefly the screening methodologies for evaluation of antimalarial activity and focuses the activity of alkaloids belonging to different structural classes as well as its importance as new antimalarial drugs or leads and chemical markers for phytomedicines.

A malária ainda é um dos mais sérios problemas de saúde pública e a principal causa de mortalidade e morbidade nas regiões endêmicas. O Brasil está entre os 30 países com maior incidência de malária e a maior parte dos casos ocorre na Amazônia Legal. Novos agentes terapêuticos são necessários para o tratamento da malária. Muitas espécies vegetais são utilizadas na medicina tradicional de vários países endêmicos mas é relativamente reduzido o número daquelas que já foram investigadas quanto à sua atividade antimalárica. Menor ainda é o número de espécies das quais foram isoladas substâncias ativas e tiveram sua toxidade determinada. Esta área de pesquisa é, portanto, de alta relevância. Um projeto de descoberta de produtos naturais antimaláricos a partir de plantas de uso tradicional deve incluir ensaios in vitro e in vivo bem como o isolamento biomonitorado de substâncias ativas. Os produtos finais serão substâncias naturais antimaláricas, potenciais fármacos ou protótipos para o desenvolvimento de novos fármacos, e/ou extratos padronizados, com atividade antimalárica, os quais são necessários para estudos pré-clínicos e clínicos quando o objetivo é o desenvolvimento de fitoterápicos (fitomedicamentos) eficazes e seguros. A presente revisão discute estas duas abordagens, apresenta resumidamente as metodologias de bioensaios para avaliação de atividade antimalárica e focaliza a atividade de alcalóides pertencentes a diferentes classes estruturais bem como sua importância como fármacos ou protótipos e como marcadores químicos de fitoterápicos.

Molluscicidal activity of Hammada scoparia (Pomel) Iljin leaf extracts and the principal alkaloids isolated from them against Galba truncatula

The molluscicidal activity of Hammada scoparia leaf extracts and the principal alkaloids isolated from them (carnegine and N-methylisosalsoline) were tested against the mollusc gastropod, Galba truncatula, the intermediate host of Fasciola hepatica in Tunisia. The results indicated that the molluscicidal activity was correlated with the presence of alkaloids. A significant molluscicidal value, according to the World Health Organization, was found with the methanol extract (LC50 = 28.93 ppm). Further fractionation of the methanolic extract led to the isolation of two principal alkaloids: carnegine and N-methylisosalsoline. These alkaloids are isoquinolines that have not previously been characterised for their molluscicidal activity. The N-methylisosalsoline possesses the highest molluscicidal activity (LC50 = 0.47 ìM against G. truncatula).

Two fast screening methods (GC-MS and TLC-ChEI assay) for rapid evaluation of potential anticholinesterasic indole alkaloids in complex mixtures

The pharmacotherapyfor Alzheimer's disease (AD) includes the use of acetylcholinesterase inhibitors (AChEI). Recent investigations for novel AD therapeutic agents from plants suggested that Tabernaemontana genus is a promising source of novel anticholinesterasic indole alkaloids. In this work two fast screening techniques were combined in order to easily identify novel cholinesterase inhibitors (ChEI). Gas chromatography-mass spectrometry (GC-MS) of the less polar alkaloidic fractions obtained from the acid-base extraction of the stalk of T. laeta revealed thirteen monoindole alkaloids, four of them confirmed by co-injection with previously isolated alkaloids. The others were tentatively identified by mass fragmentation analysis. By gas chromatography with flame ionization detection (GC-FID) and using isatin as internal standard, affinisine and voachalotine were determined as major compounds. These fractions and fourteen previously isolated alkaloids, obtained from root bark of T. laeta and T. hystrix were investigated for acetyl (AChE) and butyrylcholinesterase (BuChE) inhibitory activities by the modified Ellman's method in thin layer chromatography(TLC-ChEI). Results showed selective inhibition of the alkaloids heyneanine and Nb-methylvoachalotine for BuChE, and 19-epi-isovoacristine for AChE, whereas olivacine, affinisine, ibogamine, affinine, conodurine and hystrixnineinhibited both enzymes. In addition to confirming that monoterpenoid indole alkaloids can be novel therapeutic agents for AD, this is the first report of the ChEI activity of olivacine, a pyridocarbazole alkaloid.

Dentre os tratamentos da doença de Alzheimer (DA) está o uso de inibidores da enzima acetilcolinesterase. Pesquisas recentes visando a descoberta de novos agentes terapêuticos naturais para esta doença sugerem que o gênero Tabernaemontana é uma fonte promissora de alcalóides indólicos anticolinesterásicos. Neste trabalho, duas técnicas de análise em mistura foram associadas de modo a identificar facilmente novos inibidores colinesterásicos. A cromatografia em fase gasosa acoplada a espectrometria de massas (CG-EM) das frações alcaloídicas apolares, obtidas da extração ácido-base do caule de T. laeta, revelou a presença de treze alcalóides monoindólicos, quatro deles confirmados por co-injeção com padrões previamente isolados. Os outros alcalóides foram tentativamente identificados pelo padrão de fragmentação de massas. Por cromatografia em fase gasosa com detecção por ionização de chama (CG-DIC) e utilizando isatina como padrão interno, affinisina e voachalotina foram identificadas como substâncias majoritárias. As frações alcaloídicas obtidas e os quatorze alcalóides previamente isolados das raízes de T. laeta e T. hystrix foram analisados quanto à atividade inibitória das enzimas acetil (AChE) e butirilcolinesterase (BuChE) pelo método de Ellman em cromatografia em camada delgada (CCD-ChEI). Os resultados revelaram uma inibição seletiva dos alcalóides heyneanina e Nb-metilvoachalotina para BuChE e de 19-epi-isovoacristina para AChE, enquanto que olivacina, affinisina, ibogamina, affinina, conodurina e hystrixnina inibiram ambas as enzimas. Além de confirmar que alcalóides indólicos monoterpênicos são agentes terapêuticos promissores para o tratamento da DA, este é o primeiro relato da atividade anticolinesterásica de olivacina, um alcalóide piridocarbazólico.

Estimation of vasicine and vasicinone in ayurvedic formulations containing adhatoda vasica nees leaf extract using HPLC technique

For carrying out the estimation studies of natural Vasaka leaves [Adhatoda vasica Nees] family Acanthaceae, leaves were subjected to authentication. The marketed formulations containing the leaf extract were obtained from local pharmacies. A literature survey reveals that no specific method has been developed for the determination of amount of vasicine and vasicinone in these complex traditional formulations. The vasicine content of various formulations varied from 86.4 micro g to 22.8 micro g/10 ml of the marketed formulations. This method offers greater selectivity for the determination of the active ingredients and limiting of its oxidative product vasicinone. At the operative chromatographic condition vasicinone was not detected in any of the formulations analyzed. The HPLC technique now allows routine analysis of vasicine containing complex traditional formulation. The technique is rapid, precise and accurate and can be applied to a variety of vasicine containing formulations

Extraction of bioactive principles from Mucuna pruriens seeds.

Mucuna pruriens (L.) DC. Syn. M. prurita Hook. (Papilionaceae) is used in male impotency, as aphrodisiac, in sexual debility, and as nervine tonic. It also possesses anti-parkinson property, possibly due to the presence of L-DOPA. In the present study, attempts were made to develop the suitable method(s) for extraction of L-DOPA/other active components from the seeds using different solvents. The various extracts were also screened for their neuroprotective and antioxidant activities. In addition, TLC and HPLC fingerprinting of the extracts for amino acid components were also developed for preliminary and sophisticated analysis. The L-DOPA could be obtained in good yield on extraction with EtOH-H2O mixture (1:1) using ascorbic acid as protector. Interestingly, n-propanol extract, which contained negligible amount of L-DOPA, had shown significant neuroprotective activity, suggesting that some components, other than L-DOPA, might also be responsible for anti-Parkinson property of seeds. The extract (MW-0100) containing mainly amino acids and water-ethanol extract (1:1) (MWEL-1299) showed promising antioxidant activity (EC50 = 2.5 microg) against DPPH radicals. MWEL-1299 also exhibited encouraging results against 1-methyl-4-phenylpyridinium ion (MPP+) toxicity. The TLC fingerprinting may be used to authenticate the plant material in herbal industry.

Bromopyrrole alkaloids from marine sponge Agelas oroides

Following a bioassay-guided approach four bromopyrrole alkaloids, oroidin [1], 4,5-dibromopyrrole-2-carboxanijde [2], 4,5-dibromopyrrole-2-carboxylic acid [3] and 4,5-dibromopyrrole-2-[N methoxymethyl] carboxamide [4], were isolated from the bioactive ethyl acetate extract of the tropical marine sponge Agelas oroides. The structures of the isolated compounds were elucidated using their UV, NMR [I D and II D] and mass spectra. Fish feeding, brine shrimp, cytotoxic activity against L5178Y and Hela cell lines, protein kinase inhibition test and the antimicrobial activities for the isolated compounds were investigated. The fish-feeding assay showed that the total alcoholic extract was highly active and the major compound, oroidin, is responsible for this activity [in concentration of 80 mg/10 ml]

In vivo growth-inhibition of Sarcoma 180 by piplartine and piperine, two alkaloid amides from Piper

Piplartine {5,6-dihydro-1-[1-oxo-3-(3,4,5-trimethoxyphenyl)-2-propenyl]-2(1H)pyridinone} and piperine {1-5-(1,3)-benzodioxol-5-yl)-1-oxo-2,4-pentadienyl]piperidine} are alkaloid amides isolated from Piper. Both have been reported to show cytotoxic activity towards several tumor cell lines. In the present study, the in vivo antitumor activity of these compounds was evaluated in 60 female Swiss mice (N = 10 per group) transplanted with Sarcoma 180. Histopathological and morphological analyses of the tumor and the organs, including liver, spleen, and kidney, were performed in order to evaluate the toxicological aspects of the treatment with these amides. Administration of piplartine or piperine (50 or 100 mg kg-1 day-1 intraperitoneally for 7 days starting 1 day after inoculation) inhibited solid tumor development in mice transplanted with Sarcoma 180 cells. The inhibition rates were 28.7 and 52.3 percent for piplartine and 55.1 and 56.8 percent for piperine, after 7 days of treatment, at the lower and higher doses, respectively. The antitumor activity of piplartine was related to inhibition of the tumor proliferation rate, as observed by reduction of Ki67 staining, a nuclear antigen associated with G1, S, G2, and M cell cycle phases, in tumors from treated animals. However, piperine did not inhibit cell proliferation as observed in Ki67 immunohistochemical analysis. Histopathological analysis of liver and kidney showed that both organs were reversibly affected by piplartine and piperine treatment, but in a different way. Piperine was more toxic to the liver, leading to ballooning degeneration of hepatocytes, accompanied by microvesicular steatosis in some areas, than piplartine which, in turn, was more toxic to the kidney, leading to discrete hydropic changes of the proximal tubular and glomerular epithelium and tubular hemorrhage in treated animals.

Anti-Bacterial Alkaloids of saracococca saligna

The crude ethanolic extract of Saracococca saligna was found to be cytotoxic and antibacterial but produced no platelet aggregation induced by ADP. Antibacterial activity of two known alkaloid, pachyaximine-A and saracodme was determined. Pachyaximine-A possessed significant antibacterial activity against Escherichia coli, Staphylococcus aureus, Corynebacterium diphtheriae and Corynebacterium pyrogenes. Saracodme showed moderate activity against Staphylococcus pyrogenes, Escherichia coli, Staphylococcus aureus, Corynebacterium diphtheriae, Shigella boydii and Klebsiella pnsumoniae

Efecto in vitro de una sustancia alcaloidea aislada de Amphimedon viridis (Porifera) sobre promastigotes de Leishmania mexicana / In vitro effect of an isolated alkaloid substance from Amphimedon viridis (Porifea) on promastigots of Leishmania mexicana

The dose dependent antiproliferative effect of an alkaloidal substance extracted from the sponge Amphimedon viridis was tested on Leishmania mexicana promastigotes. Sponges were collected in Isla Larga, Venezuela (10 degrees 20' 20" - 10 degrees 24" N, 64 degrees 19' - 64 degrees 22' W), cut and dipped in methanol for vacum filtering extraction every 24 hr. The aqueous extract was separated by chromatography over silica gel. The parasites were from the Venezuelan NR strain. Their growth rate was reduced by 50% with a dose of 10 microg/ml in 48 hr, whilst concentrations of 30 and 40 microg/ml induce leishmanicidal action after 110 and 20 min, respectively. Lysis is preceded by an immediate increase in cellular volume associated with progressive damage of cellular content and the destruction of organelles. These findings suggest that one important factor associated with the antiproliferative effect of this alkaloidal substance on L. mexicana promastigotes is the loss of the plasma membrane selective permeability.

Natural probes for cholinergic sites: L-bebeerine actions on the neuromuscular transmission, the nicotinic receptor/ionic channel complex, and contraction of skeletal muscles

The mechanisms underlying the muscle relaxant of 1-bebeerine (BB), a tertiary alkaloid isolated from the roots of Chondrodendron platyphyllum, were examined in mammalian and amphibian skeletal muscles. Injections of BB (0.05 - 1 g/kg,i.p.) in rats caused a dose-related flaccid paralysis and respiratory arrest at high doses. In isolated rat diaphragmand toad sartorius muscles, BB depressed the indirectly elicited muscles twitches (IC50:228 muM and 5.4 muM, respectively, at 22 degree) and blocked the nerve-elicited muscle action potential. The neuromuscular blockade was not reserved by neostigmine (10 muM). High concentrations of BB (170 and 340 muM) caused muscle contracture unrelated to the junctional blockade, and intensified by increasing the bath temperature. Analysis of the contraction properties showed that BB (40 and 80 muM)increaded the twitch/tetanus ratio (46 percent and 125 percent) and prolonged the relaxation time; the falling phase of the directly elicited action potential in toad sartorius muscle fibers was slower probably by a decreased potasium conductance. BB (0.1 - 340 muM) reduced the binding of [1251]alpha- -bungarotoxin to the junctional AACh receptor of the rat diaphragm (IC50:47.7 muM, at 37 degree. At low concentrations BB (1.5 - 15 muM) induced either opening or blockade of the Ach receptor-ionic channel. The results showed that BB blocked noncompetitively the neuromuscular transmission through a mechanism that affects the Ach recognition site and the ionic channel properties. The alkaloid also produced muscle contracture and changed the contractile properties through its extra-junctional action at the calcium handling by the sarcoplasmic reticulum or the contractile machinery.

Botanical, chemical and pharmacological investigation on Cissampelos species from Paraíba (Brazil)

In our continuing search for biologically active compounds of local medicinal flora, we have investigated the genus Cissampelos (Meninspermaceae) whose species are used in ethnomedicine mainly for treatment of the diseases of the respiratory system. From the three species found in Paraiba: C. sympodialis, C. glaberrima and C. ovalifolia, only the first one was analyzed more extensively due to its greater availability and the high yield of warifteine, a bisbenzyltetrahydroisoquinoline alkaloid isolated from it. The water soluble fractions of the ethanolic extracts of the root, leaf and warifteine obtained from either of the fractions caused nonspecific smooth muscle relaxation in tissues such as the guinea pig trachea. The leaf fraction also showed bronchodilatory activity in whole animal experiments and inhibited human neutrophil degranulation induced by the peptide formyl-methionine-leucine-proline. The mechanism of action of the fraction involves on increase in intracellular cyclic adenosine monophosphate levels possibly as a result of the inhibition of nucleotide phosphodiesterase enzymes. The antiasthmatic use of the plant Cissampelos sympodialis may have scientific justification.