A proposito de los generos Aconitum L. y Consolida (DC.) S.F.Gray en la Peninsula Iberica.

Seguimos para este taxon, en lo nomenclatural, a TAMURA & LAUENER (1979:459), mientras no se tipifique de forma adecuada A. lycoctonum L., considerado nom. ambig. ya por TUTIN (1964:212), con pocas posibilidades de que no sea diverso de A. vulparia. A. pyrenaicum L. es también algo muy distinto del taxon que nos ocupa y, en caso de no ser aceptada la proposición de que se lo considere ñamen rejiciendum, hecha por TAMURA & LAUENER (Le.: 447), seria el nombre correcto para A. barbatum Pers. (=A. squarrosum DC.) de Siberia. Otro nombre que aún podría ser prioritario, A. altissimum Miller (WARNCKE, 1964:30; TAMURA & LAUENER, l.c), no puede usarse en tanto no se localice algún material de aquel en que se basó la descripción un tanto ambigua de Miller....

Seed morphology of Iberian Species of the genus Aconitum L.

Es presenta un estudi morfològic-biomètric de les granes deis taxons del genere Aconitum L. presents a la Península Ibérica. Es tracten aspectes que fan referencia a: 1) disposició de les granes al fol-licle, 2) definido de paramètres (forma general i ornamentado de l'episperma), 3) biometria i 4) descripció de les granes deis représentants ibérics. Els microcaràcters relacionats fonamentalment amb el relleu epispérmic, forma i ornamentado de la base d'inserció (hílum i cél-lules umbil-licals), son els que es mostren mes utils per discriminar els taxons i els que proporcionen mes informado filogenética. Els résultats que s'exposen coincideixen, en línies generals, amb els d'altres autors (SEITZ, 1969; CAPPELETTI & POLDINI, 1984). Es presenten, tanmateix, discrepancies importants pel que fa a la morfología seminal, en especial de l'ornamentació de l'episperma, en les especies A. anthora, A. napellus s.l., A. burnatii i A. vulparia subsp. ranunculifoiium. Es presenta, sovint, polimorfisme seminal en les diferentes poblacions, aïllades geogràficament, d'una mateixa especie o subspècie, tant en el context ibèric com d'Europa central i meridional. Es conclou que aquest polimorfisme és una manifestado mes de la plasticitat fenotípica del genere, particularment intensa en les especies colonitzadores d'àmplia valencia ecológica (A. napellus, s.l.; A. vulparia, s.l.), possiblement conseqiiència de la deriva genética de les poblacions.

Model studies on the synthesis of madangamine alkaloids. Assembly of the macrocyclic rings

Using simplified model derivatives, the assembly of the macrocyclic rings of madangamines, including the 13- and 14-membered D rings of madangamines C-E, the all-cis-triunsaturated 15-membered D ring of madangamine A, and the (Z,Z)-unsaturated 11-membered E ring common to madangamines A-E, has been studied.

Recent advances in lamellarin alkaloids: isolation, synthesis and activity

Lamellarins are a large family of marine alkaloids with potential anticancer activity that have been isolated from diverse marine organisms, mainly ascidians and sponges. All lamellarins feature a 3,4-diarylpyrrole system. Pentacyclic lamellarins, whose polyheterocyclic system has a pyrrole core, are the most active compounds. Some of these alkaloids are potently cytotoxic to various tumor cell lines. To date, Lam-D and Lam-H have been identified as lead compounds for the inhibition of topoisomerase I and HIV-1 integrase, respectively nuclear enzymes which are over-expressed in deregulation disorders. Moreover,these compounds have been reported for their efficacy in treatment of multi-drug resistant (MDR) tumors cells without mediated drug efflux, as well as their immunomodulatory activity and selectivity towards melanoma cell lines. This article is an overview of recent literature on lamellarins, encompassing their isolation, recent synthetic strategies for their total synthesis, the preparation of their analogs, studies on their mechanisms of action, and their structure-activity relationships (SAR).

Alkaloids and acetogenins in Annonaceae development: biological considerations

Chemical studies of the plant family Annonaceae have intensified in the last several decades due to the discovery of annonaceous molecules with medicinal potential (e.g., benzylisoquinoline alkaloids and acetogenins). Approximately 500 alkaloids have been identified in 138 Annonaceae species in 43 genera. In addition, until 2004, 593 annonaceous acetogenins (ACGs) had been identified, from 51 species in 13 genera.This suggests that plants from this family allocate important resources to the biosynthesis of these compounds. Despite the diversity of these molecules, their biological roles, including their physiological and/or ecological functions, are not well understood. In this study, it was provided new data describing the variety and distribution of certain alkaloids and ACGs in annonaceous plants in distinct stages of development. The potential relationships among some of these compounds and the seasonally climatic changes occurring in the plant habitat are also discussed. These data will improve our understanding of the secondary metabolism of these pharmacologically important molecules and their expression patterns during development, which will help to determine the optimal growth conditions and harvest times for their production.

Synthetic approaches towards the Lycopodium alkaloids

The Lycopodium alkaloids are a structurally diverse group of natural products isolated from Lycopodium with important biological effects for the potential treatment of cancer and severe neurodegenerative diseases. To date, full biological studies have been hampered by lack of material from natural sources. Total synthesis represents a possible solution to meet this demand as well as the most effective way to design new compounds to determine structural activity relationships and obtain more potent compounds. The aim of this chapter is to summarise the work carried out in this field so far by presenting an overview of the synthetic strategies used to access each of the four key Lycopodium alkaloid types. Particular emphasis has been placed on methods that rapidly construct each nucleus utilizing tandem reactions.

Synthetic approaches towards the Lycopodium alkaloids

The Lycopodium alkaloids are a structurally diverse group of natural products isolated from Lycopodium with important biological effects for the potential treatment of cancer and severe neurodegenerative diseases. To date, full biological studies have been hampered by lack of material from natural sources. Total synthesis represents a possible solution to meet this demand as well as the most effective way to design new compounds to determine structural activity relationships and obtain more potent compounds. The aim of this chapter is to summarise the work carried out in this field so far by presenting an overview of the synthetic strategies used to access each of the four key Lycopodium alkaloid types. Particular emphasis has been placed on methods that rapidly construct each nucleus utilizing tandem reactions.

Chemical constituents from Tabernaemontana catharinensis root bark: a brief NMR review of indole alkaloids and in vitro cytotoxicity

This work describes the isolation and structural determination of pharmacological compounds present in the bark of roots of Tabernaemontana catharinensis (Apocynaceae). Among the 27 substances detected 12 were identified as terpenoid-indole alkaloids, 2 steroids and 13 pentacyclic triterpenes. Structures were outlined based on HMQC, COSY, DEPT, 13C, and ¹H NMR data and MS. Spectral data of indole alkaloids were reviewed. An in vitro screening of the extracts and isolated compounds was carried out. Compounds ibogamine (5), 3-oxo-coronaridine (9) and 12-methoxy-4-methylvoachalotine (MMV) demonstrated effective cytotoxicity towards SKBR-3 breast adenocarcinoma and C-8161 human melanoma tumor cell lines.

Decrease in the diversity of pyrrolizidine alkaloids of Senecio pterophorus after invasion

Pyrrolizidine alkaloids (PAs) are N-based plant secondary metabolites that function as chemical defenses against vertebrate and invertebrate herbivores. PAs can be highly variable at intraspecific level, both in their absolute and relative concentrations. Changes in the chemical composition of exotic plants when they invade a new environment have been poorly explored. Here we studied the biogeographical variation on PAs in Senecio pterophorus (Asteraceae) in the native region in Eastern South Africa, an expanded region in Western South Africa, and two introduced regions in Australia and Europe. PAs in S. pterophorus were represented by the highly toxic 1,2-unsaturated PAs and the less toxic 1,2-saturated PAs. Our results show a change in the plant chemical composition after invasion. Total PAs concentrations were highest in Australia compared to any other region. Plants from Europe contained the highest relative concentrations of 1,2-saturated PAs. The positive correlation between the chemical and the genetic distances estimated between populations suggests that the chemical profiles in the non-native regions were related to the plant dispersal routes. The decrease in the chemical diversity and the change in the absolute PAs concentrations in S. pterophorus after invasion may have consequences in the interactions between plants and herbivores in the novel habitats.

Aporphine alkaloids from Ocotea macrophylla (Lauraceae)

Four aporphine alkaloids from the wood of Ocotea macrophylla (Lauraceae) were isolated and characterized as (S)-3-methoxy-nordomesticine (1), (S)-N-ethoxycarbonyl-3-methoxy-nordomesticine (2), (S)-N-formyl-3-methoxy-nordomesticine (3) and (S)-N-methoxycarbonyl-3-methoxy-nordomesticine (4); alkaloids 2-4 are being report for the first time. The structure the isolated compounds were determined based on their spectral data and by comparison of their spectral data with values described in literature. The alkaloid fraction and compound 1 showed antifungal activity against Fusarium oxysporum f. sp. lycopersici and also compound 1 showed antimicrobial activity towards Staphylococcus aureus, Enterococcus faecalis as well.

Bromopyrrole alkaloids from the caribbean sponge Agelas cerebrum

Bioguided fractionation of Agelas cerebrum crude extract resulted in isolation of four bromopyrrole and four bromopyrrole aminoimidazole alkaloids, identified as 5-bromopyrrole-2-carboxylic acid (1), 4-bromopyrrole-2-carboxylic acid (2), 3,4-bromopyrrole-2-carboxylic acid (3), 4,5-bromopyrrole-2-carboxylic acid (4), oroidin (5), bromoageliferin (6), dibromoageliferin (7) and dibromosceptrin (8) on the basis of spectroscopic data analyses (UV, IR, HRMS, 1D and 2D NMR) and comparison with literature data. This is the first report of compounds 2 and 3 in a marine sponge belonging to the Agelas genus and the first evidence of the presence of 1 from a natural source.

Anxiolytic-like effects of erythrinian alkaloids from erythrina suberosa

Two alkaloids, erysodine (1) and erysothrine (2) were isolated from the flowers of a Pakistani medicinal plant, Erythrina suberosa. These compounds were investigated for anxiolytic properties, and the results showed significant effect, in an acute oral treatment with 1-2, which were suspended in saline (NaCl 0.9%) plus DMSO 1%, and evaluated in 122 Swiss male mice exposed to two tests of anxiety - the elevated plus-maze (EPM) and the light/dark transition model (LDTM).

Quinoline alkaloids and friedelane-type triterpenes isolated from leaves and wood of Esenbeckia alata kunt (Rutaceae)

This work describes the phytochemical exploration of the ethanol extract from leaves and wood of Esenbeckia alata, leading to the isolation and identification of quinoline alkaloids 4-methoxy-3-(3'-methyl-but-2'-enyl)-N-methyl-quinolin-2(1 H)-one, N-methylflindersine, dictamine, kokusaginine, Γ-fagarine, flindersiamine, as well as the fridelane-type triterpenes, frideline, fridelanol and its acetate derivative. Identification of these compounds was based on full analyses of spectroscopic data (¹H, 13C, 1D, 2D, IR, MS) and comparison with data reported in literature. Compound 4-methoxy-3-(3'-methyl-but-2'-enyl)-N-methyl-quinolin-2(1 H)-one is reported for the first time for the genus Esenbeckia.

Pyrrolizidine alkaloids of senecio sp from Peru

Six pyrrolizidine alkaloids (PAs) (two saturated macrocyclic, three unsaturated macrocyclic and one unsaturated seco-macrocyclic) were isolated from native Peruvian Senecio species. The structures of these alkaloids were established by a complete NMR spectroscopic analysis, chemical transformations and comparison of their NMR data with those published for similar alkaloids. Three PAs were then tested for antifungal activity against Fusarium moniliforme, F. (Sheldon), F. oxysporum fs. lycopersici (Scheldt) and F. solani (Mart), no significant activity being observed.