Why further investigation of brazilian Strychnos?

During the past fifteen years, African Strychnos species have been pharmacologically and chemically screened by some European Universities, sometimes with the collaboration of some African Institutes. Strychnos usambarensis will be discussed here because of our interest in it, after the discovery of its use in the preparation arrow poison with curarizing activity.The European studies have show thah the African species of Strychnoschemically are very similar to certain South-American species. Indeed, the occurrence in the African species of curarizing quaternary bases, and in the American species of tetanizing tertiary bases, such as akagerine, emphasizes the unity of genus Strychnos in terms of it alkaloids. Many biological activities (antmicrobial, hypotensive, smasmolytic, amoebicial...) have been detected.Finally, the antimitotic properties of some alkaloids will be presented. Besides know antitumor drugs, e.g. alstonine and ellipticine, African species possess new antimitotic products, e.g. strychnopentamine present in Strychnos usambarensis.Because of these findings, the main reasons why further investigate Brazilian Strychnos species are the lack of knowledge about:- the distribution on the species in the southern part of the great Amazon Basin.Accordin to Krukoff, it is possible that new species may be found there.- the distribution of alkaloids in many of know species. Indeed, there is little information on the variation in compposition of the alkaloidal mixtures in the different parts of the plants.- the biological of alkaloids. In the past, interest has been focused too narrowly on possible curarizing properties.Why should Brazilian species not cantain alkaloids with properties similar to those found in the African species?

Atividade antimicrobiana de fungos endofíticos isolados de plantas tóxicas da amazônia: Palicourea longiflora (aubl.) rich e Strychnos cogens bentham

Das plantas tóxicas da Amazônia Palicourea longiflora e Strychnos cogens foram isolados 571 fungos endofíticos e 74 bactérias endofíticas. Palicourea longiflora (Rubiaceae) e outras espécies desse gênero estão relacionadas a 90% das mortes de gado na região Amazônica. Strychnos cogens (Loganiaceae) e outras espécies de Strychnos são utilizadas pelos indígenas na confecção de "curares". Entre os endófitos isolados de P. longiflora foram identificados os fungos: Colletotrichum sp. e seu telemorfo Glomerella sp., Guignardia sp., Aspergillus niger, Phomopsis sp. e Xylaria sp., além da bactéria Burkholderia gladioli, pertencente a um grupo de fixadoras de nitrogênio. Dos isolados de S. cogens foram identificados os fungos: Colletotrichum sp., Guignardia sp., Aspergillus niger e Trichoderma sp. Uma amostra de 79 isolados fúngicos teve seus metabólitos extracelulares bioensaiados contra microrganismos patogênicos e fitopatogênicos: 19 isolados inibiram um ou mais microrganismos-teste. Dos oito isolados com melhores resultados de inibição, as móleculas bioativas eram menores que 12.000 daltons, fato verificado pela diálise dos metabólitos.

Lignanas de Strychnos guianensis (Aublet) Mart.

The present communication reports the isolation and identification of three lignans from metanolic root extracts of Strychnos guianensis (Aublet) Mart.: olivil (1), cycloolivil (2) and the unknown derivative cycloolivil carbonate (3). From hexane extracts was identified a long chain fatty acid mixture and the triterpene lupeol. The analyses were based on chromatographic and spectroscopy techniques (IR, MS, GC/MS, ¹H-NMR and 13C-NMR, 1D (BB, DEPT 135) and 2D (¹H, ¹ H-COSY, ¹H, 13C-COSY, ¹H, 13C-COSY-LR, HMQC, HMBC and NOESY) and comparison with literature data.

Curare - Botany, Chemistry, and Pharmacology

Some aspects of curare research carried out over the last 25 years are discussed. Accepting a pharmacological rather than purely ethnological definition means, that curares are not limited to South America but that they are also known from Central Africa and South-EastAsia. Among the criteria that have been suggested for classifying South American curares: type of container, geographical origin, botanical sourcesof the active, constituent!, and chemical composition. A combination of botanical and geographical criteria leads to much the same regional ;groupings a combination of criteria involving the type of container and the chemical composition. The active principles in curares may derive from members of thr Loganiaceae (Strychnos) and/or Menispermaceae mainly Chondrodendron and Curarea, but also Abuta,Anomospermum, Cissampelos, Sciadotenia, and Telitoxicum). Certain of the Strychnos dimeric indole alkaloids can undergo a variety of cleavages, oxidations, and isomerizations; hence., some of the compounds obtained by normal isolation procedures one almost certainly artefacts. The different genera of, Menispermaceae a wide range of bisbenzyl and other types of isoquinoline alkaloids. Many of the plant additives also contain a variety of isoquinoline bases, and this has to be taken into account in assessing the contribution these ingredients may make to the ovzJuxll activity of, curare. Loganiaceae-bated curares with toxiferinzas major alkaloid tend to be the most toxic. In the case of Menispermaceae-based products, there-is evidence that the process by which they are made may lead to a considerable increase in the toxicity of the finished poisons as compared with the original plant materials. The mechanism of action of the alkaloids it, outlined, and the role of curare alkaloids in the development of, present-day muscle-relaxant drugs used in surgery is indicated. Attention lb drawn to reported medicinal uses of some of the alkaloid-bearing plants incorporated into curares, suggesting that further evaluation of these plants may be of interest.