Preliminary assays indicate that Antonia ovata (Loganiaceae) and Derris amazonica (Papilionaceae), ichthyotoxic plants used for fishing in Roraima, Brazil, have an insecticide effect on Lutzomyia longipalpis (Diptera: Psychodidae: Phlebotominae).
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Laboratory-reared Lutzomyia longipalpis (Lutz and Neiva 1912) was tested with extracts of two ichthyotoxic plants, known as timbos, used as fishing poison in the Amazon. Phlebotomines, L. longipalpis, and plants, Antonia ovata and Derris amazonica, were collected in the Raposa-Serra do Sol Indian Reserve, a focus of visceral leishmaniasis in the State of Roraima, Brazil. Extracts were prepared from dried leaves of A. ovata and roots of D. amazonica that were percolated in water, filtered and dried out at 50 degrees C. The solid extract obtained was diluted in water at 150, 200 and 250 mg/ml. The solution was blotted in filter paper placed at the bottom of cylindric glass tubes containing sand flies. For each plant extract and dilution, two series of triplicates with 5 male and 5 female specimens of L. longipalpis were used. Mortality was recorded every 2 h during 72 h of exposure. At 72 h the mortality was as high as 80% for extracts of A. ovata (LD50 = 233 mg/ ml), and 100% for D. amazonica (LD50 = 212 mg/ ml) whereas in the control groups maximum mortality never surpassed 13%. Preliminary assays indicated that A. ovata and D. amazonica displayed significant insecticide effect against L. longipalpis. (+info)
Genotoxicity detection of five medicinal plants in Nigeria.
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This study was performed to investigate the safety of Alchornea cordifolia, Cnestis ferruginea, Lonchocarpus sericeus, Trema orientalis, and Senna alata in respect to genotoxicity. These five medicinal plants are widely distributed in Africa. They are used as a traditional medicine in many African counties for the treatment of microbial, inflammatory, and stress-related diseases. To evaluate the bacterial reverse mutation of these five medicinal plants, the in vitro Ames test using Salmonella typhimurium TA98, TA100, TA1535, and TA1537, and Escherichia coli WP2uvrA, with or without the addition of S9 mixture was performed. Concentrations used for this test were 625, 2,500, and 5,000 microg per plate. A. cordifolia, C. ferruginea, L. sericeus, and T. orientalis showed negative results in the bacterial reverse mutation test, suggesting that it is potentially safe for these plants to be used in medicinal plants supplements at high doses. However, our experiments suggest that S. alata is a potent mutagen. Therefore, further studies are needed to evaluate the carcinogenicity of S. alata in order to adequately assess the risks for human health. (+info)
Endothelial nitric oxide-dependent vasorelaxant effect of isotirumalin, a dihydroflavonol from Derris urucu, on the rat aorta.
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The present work aimed to investigate the vasorelaxant effect of isotirumalin, a dihydroflavonol isolated from Derris urucu (Leguminosae). The vasorelaxant effect of isotirumalin was investigated in the rat aorta, in the presence and in the absence of a functional endothelium. The production of nitric oxide (NO) induced by isotirumalin was measured simultaneously with its vasorelaxation using carbon microsensors. In endothelium-intact aortic rings, isotirumalin induced a concentration-dependent vasodilator effect the concentration required to produce 30% of relaxation (pIC(3)(0)=4.84+/-0.24) that was abolished in endothelium-denuded aortic rings or in the presence of Nomega-nitro-L-arginine-methyl-ester (L-NAME; 300 microM). In addition, isotirumalin (100 microM) induced a simultaneous and significant increase on NO production, which was blunted in the presence of L-NAME. The present results demonstrate that isotirumalin is a vasodilator in the rat aorta and act by a mechanism dependent on the presence of a functional endothelium and on NO production. (+info)
A new prenylated flavanone from Derris trifoliata Lour.
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Derris scandens Benth extract potentiates radioresistance of Hep-2 laryngeal cancer cells.
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The use of herbal products as radiosensitizers is a promising approach to increase the efficacy of radiotherapy. However, adverse effects related to the use of herbal medicine on radiotherapy are not well characterized. The present study concerns the impact of Derris scandens Benth extract on the radiosensitivity of Hep-2 laryngeal cancer cells. Pretreatment with D. scandens extract prior to gamma irradiation significantly increased clonogenic survival and decreased the proportion of radiation-induced abnormal nuclei of Hep-2 cells. Furthermore, the extract was found to enhance radiation-induced G2/M phase arrest, induce Akt activation, and increase motility of Hep-2 cells. The study thus indicated that D. scandens extract potentiates radioresistance of Hep-2 cells, further demonstrating the importance of cellular background for the adverse effect of D. scandens extract on radiation response in a laryngeal cancer cell line. (+info)
Flavonoids from leaves of Derris urucu: assessment of potential effects on seed germination and development of weeds.
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