Recebido em 4/6/07; aceito em 6/9/07; publicado na web em 26/2/08 CASBANE DITERPENES AND ACETOPHENONES OF Croton nepetaefolius (EUPHORBIACEAE). Croton nepetaefolius is an aromatic plant native to the northeast of Brazil where it is extensively used in folk medicine as a sedative, orexigen and antispasmodic agent. The present work deals with the chromatographic analysis of the ethanolic extract of Croton nepetaefolius stalk. It allowed the isolation and characterization of two diterpenoids named 1,4-dihydroxy-2E,6E,12E-trien-5-one-casbane and 4-hydroxy-2E,6E,12E-5-one-casbane, two acetophenones named 2-hydroxy-4,6-dimethoxyacetophenone and 2-hydroxy-3,4,6-trimethoxyacetophenone and the steroids 3-O-β-D-glucopiranosylsitosterol and a mixture of β-sitosterol and stigmasterol. Structural elucidation was done on the basis of spectral data, mainly high field NMR and EIMS.Keywords: casbane diterpenoid; acetophenones; Croton nepetaefolius.
INTRODUÇÃOO uso de plantas com fins terapêuticos é uma tradição milenar presente nas culturas de várias nações constituindo, ainda hoje, um recurso alternativo de grande aceitação, não somente nos centros urbanos, mas sobretudo nas pequenas comunidades rurais. Este comportamento vem chamando a atenção da comunidade científi-ca no sentido de comprovar a eficácia e promover o uso seguro desses recursos naturais.1 Vale ressaltar que as plantas são fontes naturais de uma infinidade de substâncias químicas que são biossintetizadas com várias finalidades, entre elas, protegê-las contra predadores ou atrair polinizadores.
Two new diterpenes, 1 and 2, together with the known ent-15-oxo-kaur-16-en-18-oic acid (3), were isolated from the bark of Croton argyrophylloides. The structural characterization of 1 and 2 was determined on the basis of spectroscopic data interpretation. The cytotoxicity of each compound was evaluated against HL-60 (leukemia), MDAMB-435 (melanoma), SF-295 (glioblastoma), and HCT-8 (colon carcinoma) human tumor cell lines and against human peripheral blood mononuclear cells. The hemolytic potential in mouse erythrocytes was also tested for 1-3.
RESUMO:Usando reações clássicas como esterifi cação e oxidação, uma série de derivados foi obtida a partir da mistura α-e β-amirina, constituintes majoritários da resina de Protium heptaphyllum. Os compostos obtidos foram caracterizados por dados espectroscópicos como: IV, RMN de 1 H e de 13 C e comparação com dados da literatura.Unitermos: Protium heptaphyllum, Burseraceae, α-e β-amirina, derivados.ABSTRACT: "Obtention of derivatives from the α-and β-amyrin triterpenoid mixture: 13 C NMR data". Using classic reactions such as esterifi cation and oxidation, a series of derivatives was obtained from the α-and β-amyrin mixture, major compounds of the Protium heptaphyllum resin. The obtained compounds were characterized by spectroscopic data such as: IR, 1 H and 13 C NMR and comparison with literature.
Bacteria form biofilms as an adaptive mechanism in response to environmental changes. Streptococcus mutans is the biofilm-forming bacterium that is primarily associated with dental caries. The expression of important genes by bacteria in biofilms is different from that of planktonic cells. Lectins are proteins that bind specifically to carbohydrates and may have important biological activities on bacterial cells, acting as antibacterial and anti-biofilm agents. ConM (Canavalia maritima lectin) is a protein that is able to inhibit the planktonic growth and biofilm formation of S. mutans. In this context, this study aimed to evaluate the effects of ConM and concanavalin A (ConA) on the expression of genes related to virulence and biofilm formation in S. mutans. The results showed that ConM significantly reduced the expression of genes encoding enzymes related to adhesion, formation and regulation of biofilms. On the contrary, ConA did not alter the expression of the genes studied. Because the two lectins have a high degree of similarity, the differences in the actions of ConM and ConA may be explained by the small structural differences in the carbohydrate recognition domain of the lectins.
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