In Vitro Schistosomicidal Activity of Balsaminol F and Karavilagenin C

Five cucurbitane-type triterpenes (1-5), previously isolated from the African medicinal plant Momordica balsamina, along with five ester derivatives (6-10) of karavilagenin C (2), were evaluated for their potential schistosomicidal activity against Schistosoma mansoni adult worms. The natural compounds were isolated from the ethyl acetate-soluble fraction of the methanol extract of the aerial parts of M. balsamina. In a preliminary study, a significant schistosomicidal activity was observed for both the crude methanol extract and the ethyl acetate fraction. The compounds responsible for the activity were found to be balsaminol F (1) and karavilagenin C (2) with LC50 values of 14.7 +/- 1.5 and 28.9 +/- 1.8 mu M, respectively, after 24 h of incubation (positive control praziquantel, LC50 = 1.2 +/- 0.1 mu M). Both compounds (1, 2), at 10-50 mu M, induced significant reductions in the motor activity of the worms and significantly decreased the egg production. Furthermore, they were able (at 10-100 mu M) to separate the adult worm pairs into male and female after 24 h. Compounds 3-5, bearing a sugar moiety as a substituent, and the acylated derivatives of karavilagenin C (6-10) were inactive, suggesting that the presence of free hydroxyl groups in the tetracyclic skeleton might be important for the activity. A correlation between activity and the molecular volume/weight of compounds was also found.

In vitro Metabolism of Grandisin, a Lignan with Anti-chagasic Activity

Tetrahydrofuran lignans represent a well-known group of phenolic compounds capable of acting as antiparasitic agents. In the search for new medicines for the treatment of Chagas disease, one promising compound is grandisin which has shown significant activity on trypomastigote forms of Trypanosoma cruzi. In this work, the in vitro metabolism of grandisin was studied in the pig cecum model and by biomimetic phase I reactions, aiming at an ensuing a preclinical pharmacokinetic investigation. Although grandisin exhibited no metabolization by the pig microbiota, one putative metabolite was formed in a biomimetic model using Jacobsen catalyst. The putative metabolite was tested against T. cruzi revealing loss of activity in comparison to grandisin.

In vitro activity of extracts and isolated polyphenols from West African medicinal plants against Plasmodium falciparum

The aim of the study was to screen 11 selected traditional medicinal plants from West Africa for their in vitro antiplasmodial activity in order to determine the activity of single and of combination of plant extracts and to examine the activity of isolated pure compounds. Ethanolic and aqueous extracts of the 11 selected plants and pure compounds from Phyllanthus muellerianus and Anogeissus leiocarpus were tested in vitro against Plasmodium falciparum 3D7. Proliferation inhibitory effects were monitored after 48 h. Among the plants and pure compounds investigated in this study, geraniin from P. muellerianus, ellagic, gentisic, and gallic acids from A. leiocarpus, and extracts from A. leiocarpus, P. muellerianus and combination of A. leiocarpus with P. muellerianus affected the proliferation of P. falciparum most potently. Significant inhibitory activity was observed in combination of A. leiocarpus with P. muellerianus (IC50 = 10.8 mu g/ml), in combination of A. leiocarpus with Khaya senegalensis (IC50 = 12.5 mu g/ml), ellagic acid (IC50 = 2.88 mu M), and geraniin (IC50 = 11.74 mu M). In general growth inhibition was concentration-dependent revealing IC50 values ranging between 10.8 and -40.1 mu g/ml and 2.88 and 11.74 mu M for plant extracts and pure substances respectively. Comparison with literature sources of in vivo and in vitro toxicity data revealed that thresholds are up to two times higher than the determined IC50 values. Thus, the present study suggests that geraniin from P. muellerianus; ellagic acid, gallic acid, and gentisic acid from A. leiocarpus; and combination of extracts from A. leiocarpus with either P. muellerianus or K. senegalensis could be a potential option for malaria treatment.

Distribuição do Nitrogênio do Sulfato de Amônio (15N) no sistema solo-planta, em uma sucessão de culturas, sob sistema plantio direto

O aproveitamento do N pelo milho (Zea mays, L.) é influenciado pelas doses de adubo nitrogenado. O presente trabalho foi desenvolvido em um solo de textura arenoargilosa (Hapludox) e teve por objetivo avaliar a eficiência de utilização do N pela cultura de milho, em uma sucessão de culturas, utilizando-se sulfato de amônio marcado com 15N (5,5 átomos %), em diferentes doses; e o efeito residual desse fertilizante nas duas culturas subsequentes em sucessão (braquiária e milho), sob sistema plantio direto. As avaliações foram feitas em dois cultivos de milho safrinha - o primeiro no ano agrícola 2006 e o segundo em 2007 - e um de braquiária na entressafra. Os tratamentos consistiram de doses de N de 60, 120 e 180 kg ha-1, na forma de sulfato de amônio marcado (15N). Esse adubo foi aplicado em subparcelas, previamente definidas, apenas no primeiro cultivo do milho (safra 2006). Foram avaliados: N-total acumulado; N nas plantas de milho e braquiária proveniente do fertilizante, N no solo proveniente do fertilizante e recuperação de N-fertilizante pelas plantas e pelo solo. O maior aproveitamento do N-fertilizante pelo milho foi obtido no tratamento com 120 kg ha-1 de N, e o maior efeito residual do N-fertilizante pela braquiária e milho subsequente, no tratamento com 180 kg ha-1 de N. Após a sucessão de culturas, a recuperação de N pelo solo foi de 32, 23 e 27 % para os tratamentos com 60, 120 e 180 kg ha-1 de N.

Chemical constituents from three medicinal plants: Piper renitens, Siparuna guianensis and Alternanthera brasiliana

Chemical study of three medicinal plants: from leaves of Piper renitens (Miq.) Yunck, Piperaceae, and Siparuna guianensis Aubl., Siparunaceae, and from flowers of Alternanthera brasiliana (L.) Kuntze, Amaranthaceae, resulted in isolation of nine compounds: three steroids, β-sitosterol, stigmasterol from P. renitens and sitosterol-3-O-β-D-glucopyranoside from A. brasiliana, the diterpene kaurane ent-kauran-16α,17-diol from P. renitens, two derivatives kaempferol-methylether, kumatakenine (kaempferol-3,7-dimethylether) and kaempferol-3,7,3'-trimethylether from S. guianensis and three flavones, crysoeriol (5,7,4'-trihydroxy-3'-methoxyflavone), tricin (5,7,4'-trihydroxy-3',5'-dimethoxyflavone) and 7-O-β-D-glucopyranoside-5,4'-dihydroxy-3'-methoxyflavone from A. brasiliana. Compounds structures were determinate using 1D and 2D ¹H NMR and 13C spectral data, mass and IR spectra, comparing with literature data.