Melia azedarach L. extracts and their activity on Musca domestica L. (Diptera: Muscidae) / Extratos de Melia azedarach L. e sua atividade sobre Musca domestica L. (Diptera: Muscidae)

Crudes extracts and fractions from seeds of Melia azedarach L. (Meliaceae) have been assayed on Musca domestica Linnaeus, 1758 (Diptera: Muscidae). Thus, the post-embryonic development of the flies was reduced and the delay from newly hatched larvae to adults had significant increase. In addition, the pupal weights were reduced and the sexual ratio altered. Toxicity to fly eggs was also observed.

Os extratos brutos e as frações obtidas das sementes de Melia azedarach L. (Meliaceae) foram testados em Musca domestica Linnaeus, 1758 (Diptera: Muscidae). Os bioensaios mostraram inibição no desenvolvimento pós-embrionário das moscas e um significativo aumento do período larva recém eclodida- adulto. Além disso, o peso pupal foi reduzido e a proporção sexual alterada. Foi observada toxicidade para os ovos das moscas.

Effects of the essential oil obtained from Pilocarpus spicatus Saint-Hilaire (Rutaceae) on the development of Rhodnius prolixus nymphae

Bioassays against fifth-instar nymphae of Rhodnius prolixus were conducted with essential oil of Pilocarpus spicatus extracted by hydrodistillation. The main results may be summarized as follows: (i) high levels of toxicity and paralysis together with discrete moulting inhibition were caused by topical application of either 0.5 µL or 1.0 µL per insect of the crude essential oil; (ii) partial fagoinhibition, high moulting inhibition, prolonged intermoulting period and high number of paralyzed insects, but no toxicity were observed after oral treatment using either 5 µL or 10 µL of Pilocarpus spilcatus essential oil per mL of ingested blood meal. The importance of these results in relation to the relevant biological events in R. prolixus is herein discussed.

Bioensaios contra ninfas de 5º estádio de Rhodnius prolixus foram conduzidos utilizando-se óleo essencial de Pilocarpus spicatus extraído por hidrodestilação. Os principais resultados podem ser resumidos como se segue: (i) altos níveis de toxicidade e paralisia associados à discreta inibição da muda foram induzidos pela aplicação tópica de 0,5 µL ou 1,0 µL do óleo essencial por inseto; (ii) fagoinibição parcial, altos níveis de inibição da muda, período intermuda prolongado e alto número de insetos paralisados mas ausência de toxicidade foram observados após tratamento oral com 5,0 µL ou 10 µL de óleo essencial de P. spicatus por mL de sangue ingerido. A importância destes resultados em relação a eventos biológicos relevantes em R. prolixus é aqui discutida.

Secondary metabolites from marine microorganisms

After 40 years of intensive research, chemistry of marine natural products has become a mature field. Since 1995, there are signals of decreased interest in the search of new metabolites from traditional sources such as macroalgae and octocorals, and the number of annual reports on marine sponges stabilized. On the contrary, metabolites from microorganisms is a rapidly growing field, due, at least in part, to the suspicion that a number of metabolites obtained from algae and invertebrates may be produced by associated microorganisms. Studies are concerned with bacteria and fungi, isolated from seawater, sediments, algae, fish and mainly from marine invertebrates such as sponges, mollusks, tunicates, coelenterates and crustaceans. Although it is still to early to define tendencies, it may be stated that the metabolites from microorganisms are in most cases quite different from those produced by the invertebrate hosts. Nitrogenated metabolites predominate over acetate derivatives, and terpenes are uncommon. Among the latter, sesquiterpenes, diterpenes and carotenes have been isolated; among nitrogenated metabolites, amides, cyclic peptides and indole alkaloids predominate

A multidisciplinary approach to the study of the fluminense vegetation

The fluminense vegetation, more specifically the flora from the Jurubatiba restinga has been investigated by a multidisciplinary team of botanists, chemist, radiobiologist, insect physiologists and geneticist. Vouchers of 564 specimens have been collected, identified, organized in an herbarium, and a database is being build up containing, in addition to classical botanical data, chemical data and information on the potential economic use either for landscape gardening, alternative foods or as medicinal plants. Phytochemical studies of the Guttiferae, Clusia hilariana, yielded oleanolic acid and nemorosone. Their biological activities against the haematophagous insect Rhodnius prolixus vector of Chagas disease have been investigated. Finally, it has been observed that aquatic plants possessed high levels of the natural radionuclide polonium-210, which seems to be originated mainly from soil rather than from atmospheric supply

Marine natural products in Brazil. Part 1. Isolation and sctruture determination

Chemistry of marine natural products started in Brazil 35 years ago. Studies focus on invertebrates (Echinoderms, Coelenterates, Porifera, Tunicates and Mollusks) and brown algae, and to a lesser extend green algae, red algae and sharks. Some sixty different organisms have yielded over 110 identified metabolites. So far, steroids, diterpenes and sesquiterpenes have received almost all the attention. Among other metabolites, higher terpenes, long-chain lipids, tyrosine-derived dibromo compounds, two purines and one pyridine alkaloid have been described. This review reports on the history of marine natural product chemistry in Brazil and on the isolation and structure determination of these metabolites. Some unpublished results are presented.

Lignanes from the Brazilian Melia azedarach, and their activity in Rhodnius prolixus (Hemiptera, Reduviidae)

A study of the phagoinhibitor and anti-moulting activities of the Brazilian Melia azedarach, collected in the state of Rio de Janeiro, Brazil, allowed the isolation of four lignanes identified as pinoresinol, bis-epi-pinoresinol, the hemicetal and the diacid. These substances are devoid of anti-moulting activity.

Marine organisms: an alternative source of potentially valuable natural products

This paper recalls the outcoming of marine natural products research and reviews a selection of marirne bioactive metabolites in current use together with promising trends in marine pharmacology.