Seasonal influence on the essential oil of Eucalyptus microcorys.

The chemical composition of the essential oil, phenolic contents, and foliar nutrients of Eucalyptus microcorys leaves, cultivated in Brazil, was analysed on a monthly basis for one year. Canonical redundancy analysis correlated results with climate conditions (rainfall, humidity, and mean temperature), allowing three groups to be distinguished as regards temperature, flavonoids, and the content of some metals. Strong correlations between Mn, Cu, Zn, Ca, P, and K with some monoterpenes and phenolic compounds were observed. Oxygenated monoterpenes were predominant in all sampling months. Oil chemovariation may be influenced by climatic factors as well as by foliar nutrient variation.

Assessment of Duguetia furfuracea genotoxic and cytotoxic activity in bacteria and mice.

Duguetia furfuracea (St. Hil.) Benth & Hook f. (1862), popularly known as "sofre-do-rim-quem-quer" and "araticum-seco", is a shrub of the Annonaceae family that occurs in several regions of Brazil. In folk medicine the infusion of its leaves and twigs is used to treat rheumatism and renal colic, whereas the seed powder is mixed with water to treat pediculosis. Previous studies have described biological activities of this plant with cytotoxic, antitumoral, trypanocidal, leishmanicidal, antiplasmodial and antiprotozoal effects. In the present work, genotoxicity and cytotoxicity of Duguetia furfuracea lyophilized leaf extract were evaluated using the prophage λ induction test (SOS-Inductest) and mouse bone marrow micronucleus test. Our results showed that Duguetia furfuracea lyophilized leaf extract did not present an increase either in the induction of prophage λ (P>0.05) using the SOS-inductest or in the micronucleated polychromatic erythrocytes (P>0.05) using the micronucleus test, suggesting absence of genotoxicity in both tests. On the other hand, a significant decrease in the number of bacteria, (P<0.05), as well as a significant decrease in the polychromatic erythrocytes and normochromatic erythrocytes ratio, (P<0.05), were observed, showing the cytotoxic action of Duguetia furfuracea lyophilized leaf extract. Thus, Duguetia furfuracea did not present the genotoxic action, but showed a cytotoxic effect in both assays utilized in the present work.

Oenothein B inhibits the expression of PbFKS1 transcript and induces morphological changes in Paracoccidioides brasiliensis.

The fungus Paracoccidioides brasiliensis is the causative agent of paracoccidioidomycosis (PCM), the most prevalent human systemic mycosis in Latin America. Drug toxicity and the appearance of resistant strains have created the need to search for new therapeutic approaches. Plants with reputed antimicrobial properties represent a rich screening source of potential antifungal compounds. In this work, the growth of P. brasiliensis yeast cells was evaluated in the presence of oenothein B extracted from Eugenia uniflora. The oenothein B dosage that most effectively inhibited the development (74%) of P. brasiliensis yeast cells in vitro was 500 microg/ml. To verify if oenothein B interferes with cell morphology, we observed oenothein B-treated yeast cells by electron microscopy. The micrographs showed characteristic cell changes noted with glucan synthesis inhibition, including squashing, rough surface, cell wall rupture and cell membrane recess. The expression of P. brasiliensis genes was evaluated in order to investigate the action of oenothein B. Here we report that oenothein B inhibits 1,3-beta-glucan synthase (PbFKS1) transcript accumulation. The results indicate that oenothein B interferes with the cell morphology of P. brasiliensis, probably by inhibiting the transcription of 1,3-beta-glucan synthase gene, which is involved in the cell wall synthesis.

Environmental factors influence on chemical polymorphism of the essential oils of Lychnophora ericoides.

Lychnophora ericoides is a Brazilian medicinal plant used in folk medicine as an anti-inflammatory and analgesic agent. The essential oils from leaves of two populations with and without scent, collected at 2-month intervals during an 1-year period, were analysed by GC-MS. The results were submitted to principal component and cluster analysis which allowed two groups of essential oils to be distinguished with respect to sampling site and scent: cluster I (Vianópolis site, with specimens exhibiting an aromatic scent) containing a high percentage of alpha-bisabolol (44.7-76.4%) and alpha-cadinol (10.9-23.5%), and cluster II (Cristalina site, with specimens without scent) characterised by a high content of (E)-nerolidol (31.3-47.1%) and ar-dihydro-turmerone (4.8-15.4%). The canonical discriminant analysis showed that using the data set of the seven sampling months and (E)-nerolidol and alpha-bisabolol as predictable variables, it was possible to distinguish between the samples harvested according to Cerrado seasons, dry winter (May-September) and humid summer (November-March). In addition, canonical correlation analysis between the soil sampling sites and the populations revealed a significant relationship between oil components and edaphic factors. Oxygenated sesquiterpenes and potential acidity, Al saturation, cationic exchange capacity, silt, and sand load as the first canonical variate were fairly strongly related to samples collected in Vianópolis site. On the other hand, monoterpenes and sesquiterpene hydrocarbons were strongly related to chemical balance in soils (organic matter, P and base saturation), which is related to samples at the Cristalina site. The chemovariation observed appears to be environmentally determined.

Avaliação da atividade larvicida de plantas fitoterápicas do cerrado do gênero Stryphnodendron spp. sobre miracídios e cercárias de Schistosoma mansoni / Evaluation of the larvicidal activity of phytotherapic brazilian savannah plants of the genus Stryphnodendron spp. on Schistosoma mansoni miracidia and cercariae

A esquistossomíase é uma doença endêmica causada por parasitos do gênero Schistosoma, sendo somente Schistosoma mansoni observado no Brasil. No presente trabalho, o potencial das plantas do Cerrado brasileiro. Stryphnodendron polyphyllum e Stryphnodendron adstringens, foi testado como fonte alternativa de produtos naturais utilizados contra miracídios e cercárias, as formas infectantes de S. mansoni. A partir dos extratos brutos EAA (extração acetona: água) das cascas dos caules preparam-se soluções-mãe de 400 ppm, que foram diluídas até se obterem as concentrações de 100 e 200 ppm para os bioensaios com miracídios, e de 20, 50, 100 e 200 ppm para os bioensaios com cercárias. Nos testes com miracídios, estas plantas demonstraram atividade somente 5 horas e 30 minutos após o contato inicial com os extratos, enquanto o grupo-controle sobreviveu por oito horas nas mesmas condições. A mortalidade das cercárias ocorreu apenas uma hora após o início dos experimentos em todas as concentrações testadas para as duas espécies vegetais. O grupo-controle sobreviveu, em água, por 36 horas após o início dos experimentos. Estes dados confirmam a presença, no Cerrado brasileiro, de plantas com potencial bioativo no combate às cercárias, forma infectante de S. mansoni para mamíferos.

Tannin composition of barbatimão species.

A comparative study of tannin composition of three species known as barbatimão (Stryphnodendron adstringens, Stryphnodendron polyphyllum and Dimorphandra mollis) was developed by TLC, hydrolysis followed by PC, and colorimetry. Principal component analysis of the data obtained showed strong differentiation between the genus Dimorphandra and Stryphnodendron. Additionally, barks from the two Stryphnodendron sp. also presented considerable differences in the tannin structure.