Bioactive sesquiterpene pyridine alkaloids from Maytenus aquifolium

Two new sesquiterpene evoninate alkaloids, were isolated together with the known compounds syringaresinol and 4'-O-methyl-(-)-epigallocatechin from the root bark of Maytenus aquifolium. The structures of the two alkaloids were elucidated by interpretation of their spectral data, and both exhibited very weak activity in a mechanism-based DNA-modifying yeast assay. (C) 1998 Elsevier B.V. Ltd. All rights reserved.

ALKALOIDS FROM ARISTOLOCHIA-ARCUATA

Phytochemical studies with Aristolochia arcuata led to the isolation of KNO3, fructose, sucrose, sitosterol, calarene, its 2-oxo derivative, and three neolignans. Besides which, two new 13-oxidodibenzo[a, g]-quinolizinium alkaloids were isolated. They present only one oxygenated substituent at rings A and D.

Indolizidine 239Q and quinolizidine 275I. Major alkaloids in two Argentinian bufonid toads (Melanophryniscus)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Bioactive guanidine alkaloids from Pterogyne nitens

Bioactivity-guided fractionation of a methanolic CHCl 3 extract of the leaves of Pterogyne nitens afforded the known guanidine alkaloid pterogynidine [2] and three new guanidine alkaloids, nitensidines A [3], B [4], and C [5], all of which exhibited selective activity towards the DNA repair-deficient yeast mutant RS 321 (IC 12=9.3-20.0 μg/ml); 3,4, and 5 were moderately cytotoxic to CHO Aux B 1 cells (IC 50=8.5-13.0 μg/ml).

Further sesquiterpene pyridine alkaloids from Maytenus aquifolium

Two new sesquiterpene evoninate alkaloids, aquifoliunine E-III and aquifoliunine E-IV, were isolated from the root bark of Maytenus aquifolium. The structures of the new compounds were elucidated on the basis of spectroscopic methods, including ES-MS.

Evaluation of Strychnos pseudoquina St. Hil. leaves extract on gastrointestinal activity in mice

Strychnos pseudoquina St. Hil. (Loganiaceae) was investigated for its ability to protect the gastric mucosa against injuries caused by non-steroidal anti-inflammatory drugs (piroxicam) and a necrotizing agent (HCl/EtOH) in mice. The MeOH extract and enriched alkaloidic fraction (EAF) provided significant protection in experimental models wheer used at doses of 250 and 1000 mg/kg. In vivo tests were carried out to evaluate for possible toxic effects and no mortality was observed up to the 5 g/kg dose level. Phytochemical investigation led to the isolation of a new indole alkaloid, which elucidated the observed pharmacological effects. © 2005 Pharmaceutical Society of Japan.

Electrospray ionization mass spectrometry screening of piperidine alkaloids from Senna spectabilis (Fabaceae) extracts: Fast identification of new constituents and co-metabolites

The fragmentation pattern of a homologous series of piperidine alkaloids isolated from S. spectabilis was investigated using electrospray ionization tandem mass spectrometry (ESI-MS/MS). The ESI-MS and ESI-MS/MS analyses of EtOH extracts and fractions from flowers and fruits of S. spectabilis allowed to elucidate the structures of four new compounds. The identification of these co-metabolites, based on the fragmentation patterns of previously isolated compounds, and further confirmed by accurate mass spectrometry defines this technique as a powerful tool to determine the metabolomic profile of species which has pharmacological importance. ©2005 Sociedade Brasileira de Química.

Intraspecific and intracolonial variation in the profile of venom alkaloids and cuticular hydrocarbons of the fire ant Solenopsis saevissima smith (Hymenoptera: Formicidae)

Fire ants are aggressive Neotropical ants that are extensively similar in general biology and morphology, making species identification difficult. Some fire ant species are top-rated pests spreading throughout the world by trade vessels. Many researchers attempted to sort between invasive and native species by using chemical characters, including patterns of venom alkaloids. The present study is the first to report intraspecific variation in some chemical characters, namely, cuticular hydrocarbons and venom alkaloids, within the Brazilian fire ant species Solenopsis saevissima and also reports on within-nest variations among members of different castes. Two different haplotypes (cryptic species) of S. saevissima were clearly identified, one presenting a predominant combination of the venom alkaloids cis- and trans-2-methyl-6-undecylpiperidine with the cuticular hydrocarbons C23, 3-Me-C23, 10-C 25:1, C25, and 3-Me-C25, and the other a predominant combination of cis- and trans-2-methyl-6-tridecenylpiperidine with predominance of 12-C25:1, C25, 11-Me-C25, 3-Me-C25, 13-C27:1, C27, and 13-Me-C 27. Intranest variations revealed that the proportions among these compounds varied sensibly among workers of different sizes, gynes, and males (no alkaloids were detected in the latter). Larva contained vestiges of the same compounds. The recorded chemical profiles are quite different from previous reports with S. saevissima samples from So Paulo. The finds thus support other recent claims that S. saevissima includes cryptic species; the study, moreover, adds the find that they can occur in the same geographical location. © 2012 Eduardo Gonalves Paterson Fox et al.

Solanidane and iminosolanidane alkaloids from Solanum campaniforme

From the leaves of Solanum campaniforme (Solanaceae), eight solanidane alkaloids were isolated, four of which contain a p-hydroxyphenylethylamine unit. Their structures were established as: 22β,23β-epoxy-solanida-1,4-dien-3-one; 22α,23α-epoxy-10-epi-solanida-1,4,9-trien-3-one; 22α,23α-epoxy-solanida-4-en-3-one; 22β,23β-epoxy-solanida-4-en-3-one; (E)-N-[8′(4-hydroxyphenyl)ethyl]-22α,23α-epoxy-solanida-1,4,9-trien-3-imine; (E)-N-[8′(4-hydroxyphenyl)ethyl]-22α,23α-epoxy-solanida-1,4-dien-3-imine; (Z)-N-[8′(4-hydroxyphenyl)ethyl]-22α,23α-epoxy-solanida-1,4,9-trien-3-imine and (Z)-N-[8′(4-hydroxyphenyl)ethyl]-22α,23α-epoxy-solanida-1,4-dien-3-imine. All structures were determined using spectroscopic techniques, such as 1D and 2D NMR, and HRESIMS. The cytotoxicity and the antiophidic activities of the alkaloids were evaluated. The alkaloids did not show any cytotoxicity, but inhibited the main toxic actions of Bothrops pauloensis venom. © 2013 Elsevier Ltd. All rights reserved.

Detecção in silico dos constituintes majoritários de Strychnos brasiliensis e S. pseudoquina (Loganiaceae) usando CLAE-DAD/EMAR

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Coumarins and Alkaloids from the Stems of Metrodorea Flavida

Uma nova cumarina , a 5,6-metilenodioxi-7,8-dimetoxicumarina, foi isolada a partir dos galhos de Metrodorea flavida, juntamente com outras cumarinas e alcalóides conhecidos. As estruturas das substâncias isoladas foram definidas por análises de seus dados espectrais , bem como por comparação com dados da literatura.

Alkaloids and volatile constituents from the stem of Fusaea longifolia (Aubl.) Saff. (Annonaceae)

ABSTRACT: A phytochemical study of the ethanol extract and an extraction of the volatile compounds, performed by means of Clevenger apparatus were carried out with the stem of Fusaea longifolia (Aubl.) Saff. (Annonaceae). The ethanol extract yielded O-methylmoschatoline, isolated for the first time in this species, and stepholidine, reported for the first time in genus Fusaea. The structural identification of the alkaloids was made based on the analysis of their NMR spectra. Through the use of GC and GC-MS, two sesquiterpenoids, a-cadinol (12.5%) and spatulenol (12.0%) were identified as the major constituents of the essential oil.

Plant-derived antimalarial agents: new leads and efficient phythomedicines. Part I. Alkaloids

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.

Erythrina mulungu Alkaloids Are Potent Inhibitors of Neuronal Nicotinic Receptor Currents in Mammalian Cells

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)