Two new triterpene glucosides, β-d-glucopyranosyl 2α,3β,24-trihydroxyolean-12-en-28-oate and β-d-glucopyranosyl 2α,3β,23,24-tetrahydroxyurs-12-en-28-oate, in addition to nine known compounds belonging to three different triterpene classes (oleanane-, ursane- and lupane-type) have been isolated from the stems of a specimen of Combretum laxum growing in the “Pantanal” of the central-western region of Brazil. Among the known triterpenes, β-d-glucopyranosyl 2α,3β,6β-trihydroxyolean-12-en-28-oate is reported for the first time in the Combretaceae, while bellericoside and asiatic acid are described for the first time in the genus Combretum. The structures of the isolated compounds have been established on the basis of spectral techniques (1D-, 2D-NMR and MS). Their in vitro antifungal activities against standard strains of Candida albicans, C. krusei and Cryptococcus neoformans were also evaluated in this work.

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Recebido em 19/5/08; aceito em 6/10/08; publicado na web em 2/2/09 PHENYLPROPANOIDS AND OTHER BIOACTIVE CONSTITUENTS FROM NECTANDRA MEGAPOTAMICA. From the trunk bark of Nectandra megapotamica (Lauraceae) four phenylpropanoids, elemicin, isoelemicin, (±)-erythro-1-(3,4,5-trimethoxyphenyl)-1,2-propanediol and (±)-threo-1-(3,4,5-trimetoxyphenyl)-1,2-propanediol have been isolated, in addition to 3,4,5-trimethoxybenzoic acid, (-)-epicatechin and trans-1(10)-epoxy-4(15)-caryophyllene. The diastereoisomeric erythro-and threo-phenylpropanoids are being reported for the first time in a plant taxon as well as the occurrence of the other compounds in Nectandra. The structures of the isolated compounds have been established on the basis of 1D and 2D NMR spectroscopic techniques. Their in vitro antifungal activities against standard strains of Candida albicans, C. krusei, C. tropicalis and Cryptococcus neoformans and antioxidant properties were also evaluated in this work.Keywords: Nectandra megapotamica; Lauraceae; phenylpropanoids. introduÇÃoA família Lauraceae engloba cerca de 52 gêneros e 3 mil espécies dispersos predominantemente nas regiões tropical e subtropical do planeta, especialmente nas matas centro-e sul-americanas, sendo excepcionalmente encontradas em zonas temperadas. No Brasil, é representada por 22 gêneros, compreendendo espécies em geral arbóreas. 1 Nectandra é um dos principais gêneros de Lauraceae no Novo Mundo, com 114 espécies distribuídas em todos os biomas da América tropical e subtropical, sendo encontrados no Brasil 43 representantes. 2 Em Mato Grosso do Sul foram relatadas 8 espécies de Nectandra (N. amazonum, N. cissiflora, N. cuspidata, N. falcifolia, N. gardneri, N. hihua, N. megapotamica e N. psammophila). 3 Nectandra megapotamica, conhecida popularmente por "canelapreta", ocorre desde o sul de Minas Gerais até o Rio Grande do Sul e também na região Centro-Oeste, sendo que em Mato Grosso do Sul é encontrada nas regiões central e sul do estado. 3,4 A literatura relata 5 trabalhos realizados com espécimes desta planta coletados no estado de São Paulo, 3 dos quais relacionados a atividades biológicas de alguns de seus constituintes químicos. Das cascas do caule foram obtidos dois alcalóides (N-metiltriptamina e 6-metóxi-N-metil-1,2,4-tetraidro-β-carbolina) inibidores do crescimento in vitro de Crithidia fasciculata e Trypanosoma cruzi. 5 Outro estudo realizado com as cascas do caule forneceu um fenilpropanóide (α-asarona) que apresentou atividade analgésica, além das neolignanas tetraidrofurânicas galgravina e veraguensina com atividade antiinflamatória em ratos e camundongos, enquanto que das folhas foram obtidas onze neolignanas tetraidrofurânicas, três das quais com atividade tripanocida in vitro. 6 A investigação da composição química de lauráceas que ocorrem no Cerrado e Pantanal de Mato Grosso do Sul, incluindo as do gênero Nectandra, tem sido motivo de estudos desenvolvidos por nosso grupo de pesquisa. 7 Nas coletas de plantas realizadas, constatamos a presença de Nectandra megapotamica ...

Recebido em 16/7/10; aceito em 25/10/10; publicado na web em 18/2/11 SEMI-PREPARATIVE SEPARATION OF a AND b-AMYRIN BY HIGH PERFORMANCE LIQUID CHROMATOGRAPHIC. The resin obtained from species of the genus Protium (Burseraceae) is formed mostly of pentacyclic triterpenes: a-amyrin and b-amyrin. The separation and purification of these triterpenes were optimized in three steps.Keywords: Protium; HPLC; separation of a-amyrin and b-amyrin. INTRODUÇÃOOs triterpenos apresentam ampla diversidade estrutural, podendo ser tetracíclicos, pentacíclicos e acíclicos.1 A maioria dos triterpenos pentacíclicos pertence às subclasses ursano, oleanano e lupano.1 Estão presentes como constituintes majoritários de resinas produzidas por um grande número de espécies vegetais, entre as quais destacam-se as espécies do gênero Protium (Burseraceae). Este gênero é amplamente distribuído na América do Sul, em especial na Amazônia.As resinas produzidas por espécies do gênero Protium possuem aplicação industrial, com uso em perfumaria, na confecção de vernizes e para a calafetação de embarcações. Na medicina popular são utilizadas como repelentes de insetos, expectorantes e no tratamento de diversas enfermidades. Há na literatura vários trabalhos que descrevem a atividade anti-inflamatória, antinociceptiva, imunoestimulante e antineoplásica dessas resinas. 2-4Os constituintes majoritários das resinas de Protium são os triterpenos pentacíclicos a e b-amirina. Tanto as misturas de acetato como o cinamato de a e b-amirina apresentam significativa atividade antiinflamatória e, ainda, ação antiartrite e analgésica, respectivamente. 3,4 Todavia, estas atividades foram resultados de ensaios biológicos feitos com estes triterpenos em mistura. Assim, o potencial biológico não foi estabelecido para estes derivados da a e b-amirina individualmente.Neste trabalho descreve-se o uso da cromatografia líquida de alta eficiência (CLAE) no modo preparativo para a purificação dos isôme-ros triterpenos a-amirina e b-amirina. A separação da a e b-amirina em mistura é praticamente impossível de ser alcançada utilizando-se técnicas cromatográficas de baixa eficiência. PARTE EXPERIMENTAL Reagentes e instrumentosForam utilizados reagentes com grau de pureza CLAE e água ultrapura (MilliQ). Acetonitrila (Tedia, Rio de Janeiro, Brasil) foi usada como modificador de polaridade da fase móvel. Para cromatografia clássica em coluna usou-se os solventes orgânicos de grau P.A. (Tedia) e gel de sílica 0,063 a 0,200 mm, 70-230 mesh ASTM (E. Merck, Darmstadt).

A total of 42 ethanolic extracts from 30 different plant species, native to the Pantanal and Cerrado of the West-Central region of Brazil, have been evaluated for their larvicidal activity against Aedes aegypti larvae, the vector of dengue and dengue hemorrhagic fevers. Among the extracts tested, that obtained from the trunk bark of Ocotea velloziana was the most active. Using a bioassay-directed fractionation of this extract, the active constituent was isolated and characterized as the aporphine alkaloid (+)-dicentrine. Its structure was established on the basis of (1)H and (13)C NMR spectra, optical rotation and by comparison with an authentic sample. This is the first report on the larvicidal activity against A. aegypti of this alkaloid. Our results suggest that (+)-dicentrine may be considered as a promising natural mosquito larvicidal agent.

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Ethanol extracts from six selected species from the Cerrado of the Central-Western region of Brazil, which are used in traditional medicine for the treatment of infectious diseases and other medical conditions, namely Erythroxylum suberosum St. Hil. (Erythroxylaceae), Hyptis crenata Pohl. ex Benth. (Lamiaceae), Roupala brasiliensis Klotz. (Proteaceae), Simarouba versicolor St. Hil. (Simaroubaceae), Guazuma ulmifolia Lam. (Sterculiaceae) and Protium heptaphyllum (Aubl.) March. (Burseraceae), as well as fractions resulting from partition of these crude extracts, were screened in vitro for their antifungal and antibacterial properties. The antimicrobial activities were assessed by the broth microdilution assay against six control fungal strains, Candida albicans, C. glabrata, C. krusei, C. parapsilosis, C. tropicalis and Cryptococcus neoformans, and five control Gram-positive and negative bacterial strains, Escherichia coli, Enterococcus faecalis, Klebsiella pneumoniae, Pseudomonas aeruginosa and Staphylococcus aureus. Toxicity of the extracts and fractions against Artemia salina was also evaluated in this work. All plants investigated showed antimicrobial properties against at least one microorganism and two species were also significantly toxic to brine shrimp larvae. The results tend to support the traditional use of these plants for the treatment of respiratory and gastrointestinal disorders and/or skin diseases, opening the possibility of finding new antimicrobial agents from these natural sources. Among the species investigated, Hyptis crenata, Erythroxylum suberosum and Roupala brasiliensis were considered the most promising candidates for developing of future bioactivity-guided phytochemical investigations.

BackgroundThe influenza virus can cause seasonal infections with mild to severe symptoms, circulating worldwide, and it can affect people in any age group. Therefore, this infection is a serious public health problem that causes severe illness and death in high-risk populations. Every year, 0.5% of the world’s population is infected by this pathogen. This percentage can increase up to ten times during pandemics. Influenza vaccination is the most effective way to prevent disease. In addition, anti-influenza drugs are essential for prophylactic and therapeutic interventions. The oseltamivir (OST, a neuraminidase inhibitor) is the primary antiviral used in clinics during outbreaks. However, OST resistant viruses may emerge naturally or due to antiviral pressure, with a prevalence of 1–2% worldwide. Thus, the search for new anti-influenza drugs is extremely important. Currently, several groups have been developing studies describing the biotechnological potential of microalgae and cyanobacteria, including antiviral activity of their extracts. In Brazil, this potential is poorly known and explored.MethodsWith the aim of increasing the knowledge on this topic, 38 extracts from microalgae and cyanobacteria isolated from marine and freshwater biomes in Brazil were tested against: cellular toxicity; OST-sensitive and resistant influenza replications; and neuraminidase activity.ResultsFor this purpose, Madin-Darby Canine Kidney (MDCK)-infected cells were treated with 200 μg/mL of each extract. A total of 17 extracts (45%) inhibited influenza A replication, with seven of them resulting in more than 80% inhibition. Moreover, functional assays performed with viral neuraminidase revealed two extracts (from Leptolyngbya sp. and Chlorellaceae) with IC50 mean < 210 μg/mL for influenza A and B, and also OST-sensitive and resistant strains. Furthermore, MDCK cells exposed to 1 mg/mL of all the extracts showed viability higher than 80%.DiscussionOur results suggest that extracts of microalgae and cyanobacteria have promising anti-influenza properties. Further chemical investigation should be conducted to isolate the active compounds for the development of new anti-influenza drugs. The data generated contribute to the knowledge of the biotechnological potential of Brazilian biomes that are still little explored for this purpose.