In Cambodia, 1,303 bats of 16 species were tested for lyssavirus. No lyssavirus nucleocapsid was detected in 1,283 brains tested by immunofluorescence assay. Antibodies against lyssaviruses were detected by enzyme-linked immunosorbent assay in 144 (14.7%) of 981 serum samples. Thirty of 187 serum samples contained neutralizing antibodies against different lyssaviruses.
Malaria is a major health concern particularly in Africa which has about 90% of the worldwide annual clinical cases. The increasing number of drug-resistant Plasmodium falciparum justifies the search for new drugs in this field. Antimalarial activity of 2-substituted 6-nitro- and 6-amino-benzothiazoles and their anthranilic acids has been tested. An in vitro study has been performed on W2 and 3D7 strains of P. falciparum and on clinical isolates from malaria-infected patients. Toxicity has been assessed on THP1 human monocytic cells. For the most active drug candidates, the in vitro study was followed by in vivo assays on P. berghei-infected mice and by in vitro assays in order to determine the stage-dependency and the mechanism of action. Of 39 derivatives tested in vitro, 2 had specific antimalarial properties. Each compound was active on all stages of the parasite, but one was markedly active on mature schizonts, while the other was more active on young schizont forms. Both drugs were also active on mitochondrial membrane potential. In vivo data confirmed efficiency with a sustained decrease of parasitaemia. Products A12 and C7 may be considered as potential antimalarial worthy of further chemical and biological research.
Terpenes U 0200 Antimalarial Activity of Sesquiterpene Lactones from Vernonia cinerea. -The new sesquiterpene lactones vernolide C (Ia) and D (Ib) and six known analogues are isolated from the dichloromethane fraction of an aqueous extract. -(CHEA, A.; HOUT, S.; LONG, C.; MARCOURT, L.; FAURE, R.; AZAS, N.; ELIAS*, R.; Chem.
Vernonia cinerea LESS (Asteraceae) is a perennial herbaceous plant mainly distribued in the tropical regions and commonly found in South-East Asia.1,2) Many therapeutic uses were reported for this plant, especially for the treatment of malaria fever and liver diseases. 3,4) In Cambodia, V. cinerea is called 'Kbal Ruy' by local residents, and is widely used as a traditional medicine for the treatment of fever and colics.1,5) An ethnobotanical survey in different regions of Cambodia indicated that this plant was found to be used as a febrifuge against malaria.6) It is worth noting that a far better antiplasmodial activity was found in the dichloromethane extract prepared from a decoction of the plant, compared with the dichloromethane extract directly prepared from the dried plant. The former extract was subjected to silica gel chromatography to yield two new sesquiterpene lactones, vernolides C 4 and D 8 (Fig. 1), along with six known compounds. This paper reports the identification and structural determination of the isolated compounds on the basis of spectroscopic analysis, including two-dimensional NMR and HR-ESI-MS data.The dichloromethane extract obtained from a decoction of the whole plant was subjected to repeated column chromatography affording eight sesquiterpene lactones as described in the Experimental section. By comparison of the physical and spectroscopic data of the compounds with literature reports on the same plant, 7) 1, 3 and 7 were identified as 8a-tigloyloxy-hirsutinolide-13-O-acetate, 8a-tigloyloxyhirsutinolide and 8a-(4-hydroxymethacryloyloxy)-hirsutinolide-13-O-acetate, respectively. Three further known lactones: 8a-epoxymethacryloyloxy-hirsutinolide-13-O-acetate 2, hirsutinolide-13-O-acetate 5 and piptocarphin D 6, described here for the first time in this plant, have been identified by comparison of their spectroscopic data with those published in the literature. [8][9][10][11][12][13][14] Vernolide C 4 was shown to be a chlorinated compound according to the typical cluster of ions in the mass spectrum at m/z 481 and 483; high resolution analysis of these ions as well as matching of isotopes allowed the composition to be determined as C 21 15) Detailed examination of the chemical shifts and long range CH correlations confirmed that the compound belonged to the hirsutinolide series with a proton onto C-10. That the hydrochlorination had taken place on the epoxide was shown by the presence of an AB quartet featuring H-3Ј of the ester side chain; all of the expected CH couplings be- Two new sesquiterpene lactones, vernolides C and D as well as six known ones were isolated from the dichloromethane fraction of an aqueous extract from Vernonia cinerea. Their structures were elucidated by spectroscopic methods. Among the known sesquiterpene lactones, three of them were described in this plant for the first time. In vitro antiplasmodial evaluation showed that the three major compounds 1, 7 and 8 were active against chloroquine resistant Plasmodium falciparum strain (W2) with IC 50 3.9, 3.7 and...
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