Biomedical subjects
Publications and source records attributed to A Fournet.
The larvicidal activity against Aedes aegypti larvae of a stem wood hexane extract of Cybistax antisyphilitica was evaluated. Bioassay-guided fractionation of the crude extract, monitored by larvicidal assay, led to the isolation of a natural quinone identified as 2-hydroxy-3-(3-methyl-2-butenyl)-1.4-naphthoquinone (lapachol). This compound was quite potent against A. aegypti larvae (LC50 26.3 microg/ml).
Twenty plants, belonging to sixteen families, used in traditional New Caledonian and Vanuatu medicine for treatment of symptoms potentially related to tuberculosis (cough, fever or inflammation) were screened for antimycobacterial activity. We also screened an original endemic plant, Amborella trichopoda, only member of the monogeneric family Amborellaceae and considered the most primitive living angiosperm. In total, 55 extracts were evaluated for inhibitory activity against Mycobacterium bovis BCG strain at a concentration of 100 microg/ml. Methanolic and dichloromethane extracts of Amborella trichopoda, Codiaeum peltatum, Myristica fatua, and essential oils Myoporum crassifolium showed an activity at this concentration. Methanolic extract of Amborella trichopoda fruits presented a significant activity with a minimal inhibitory concentration included between 1 and 2.5 microg/ml. In the same conditions, this activity was comparable with those of the reference drugs pyrazynamide and ethambutol, at 20 and 2.5 microg/ml, respectively.
Sixty-seven extracts of 30 medicinal plants traditionally used in New Caledonia or Vanuatu by healers to treat inflammation, fever and in cicatrizing remedies were evaluated in vitro for their antiprotozoal activity against Leishmania donovani, Leishmania amazonensis and Trypanosoma cruzi. Among the selected plants, Pagiantha cerifera was the most active against both Leishmania species; four extracts were active against promastigotes of Leishmania donovani at EC(50) values inferior to 5 microg/ml. Garcinia pedicillata extract had an EC(50) value of 12.5 microg/ml against intracellular amastigotes of Leishmania amazonensis. Alone Amborella trichopoda reduced by more of 80% the trypomastigotes of Trypanosoma cruzi in the blood.
The crude alkaloidal extract of Zanthoxylum chiloperone stem bark exhibited in vitro activity against various strains of Leishmania ssp. at 100 microg/ml. Two active major constituents were isolated and identified as canthin-6-one and 5-methoxycanthin-6-one. The effect of these compounds was also tested in an in vivo assay using BALB/c mice infected with Leishmania amazonensis. The mice were treated for 5 weeks postinfection with these alkaloids by oral (14 days) or intralesional route (4 days) at 10 mg/kg daily. The reference drug, N-methylglucamine antimonate was administered by subcutaneous injections at 100 mg/kg for 10 days. Intralesional administration of canthin-6-one reduced the parasite burden but not significantly when it was compared with the untreated group, while the reference drug reduced by 91% the parasite loads in the lesion.
It was reported previously that 2-n-propylquinoline was active against the epimastigote form of Trypanosoma cruzi. The effects of oral treatments with benznidazole and 2-n-propylquinoline were evaluated in Balb/c mice infected with T. cruzi chronically. The reference drug and 2-n-propylquinoline were administered 60 days post-infection for 30 days at 25 mg/mL. At 35 days post-treatment, the serological tests (ELISA) of the 2-n- propylquinoline-treated mice were significantly different from the controls (p = 0.01) and the benznidazole-treated mice (p = 0.03), while this was not the case at 85 days post-treatment. These results are encouraging for continuing the investigation of other analogues of 2-n-propylquinoline in experimental chronic Chagas' disease.
PURPOSE: The stability of 5-fluorouracil (FU) Roche solutions in a portable infusion pump under prolonged "in-use" conditions (32 degrees C, in the dark) was studied, especially with respect to the formation of the cardiotoxic compounds fluoroacetaldehyde (Facet) and fluoromalonic acid semialdehyde (FMASAld). METHODS: The solutions, prepared according to three protocols frequently used at the Anticancer Centre in Toulouse, were analysed by 19F NMR immediately after preparation (T0) and after 2, 3 or 10 days (TF) in the pump. RESULTS: The commercial solution already contained 64 fluorinated "impurities", among them fluoride ion (F-), FMASAld and Facet. The concentration of FU did not change significantly between T0 and TF, whatever the protocol. The levels of F- had not increased significantly after 2 or 3 days, but had increased by about 50% after 10 days. The increases in FMASAld levels were low (12-28%) albeit significant in the three protocols. The levels of Facet had increased by a factor of about 2 after 2 or 3 days, and by a factor of > 3 after 10 days. The levels of the other fluorinated compounds were constant during the first 2 or 3 days, but had increased by about 30% after 10 days. FU Dakota lyophilizates, analysed immediately after reconstitution, contained neither FMASAld nor Facet. After 2 days at 25 degrees C, low levels of FMASAld were present but Facet could still not be detected. CONCLUSION: This study showed that special attention must be paid to the risk of increasing concentrations of highly toxic FMASAld and Facet when FU is administered via a pump for long periods of time. It would be preferable not to exceed 3 days of treatment when patients receive FU from a portable infusion pump. This underlines the interest in using a lyophilized formulation of FU in clinical practice.
Together with known alkaloids, five new bisbenzylisoquinoline derivatives were isolated from the stem bark of Guatteria boliviana (Annonaceae), puertogalines-A 1 and -B 2, (+)-guatteboline 3, philogaline 4 and (-)-antioquine 5. Their structures were elucidated by spectrometric methods and their antiparasitic activity was evaluated in vitro on Leishmania sp., Trypanosoma cruzi and Plasmodium falciparum. Their cytotoxic activity was also measured in KB cell line.
We have shown previously that daphnoline and cepharanthine are active against Trypanosoma cruzi and inhibited trypanothione reductase. The effects of oral treatments with daphnoline, cepharanthine and benznidazole were examined in Balb/c mice infected with T. cruzi acutely and chronically. In acute infections, parasitaemia was significantly reduced in the daphnoline-treated mice compared with controls and benznidazole-treated mice. The parasitological cure rate was increased in mice treated with daphnoline. Fifty days after infection, the negative serological response in both models was significantly different for the three tested drugs. Daphnoline showed the highest negative serological rate (48%). In chronically infected mice treated with daphnoline, we were unable to detect parasites in 70% of mice. The results obtained of oral treatment of daphnoline suggest that this bisbenzylisoquinoline may be useful in the treatment of acute and chronic Chagas' disease. This was not seen with cepharanthine, an excellent trypanothione reductase inhibitor.
Two new annonaceous acetogenins, cohibins C (1a) and D (1b), have been isolated by extensive chromatography of a hexane extract of Annona muricata seeds and a cyclohexane extract of Annona nutans root bark. Their structures have been established on the basis of spectral evidence (NMR, MS) and confirmed by chemical transformation into a pair of monotetrahydrofuran (mono-THF) acetogenins. The role of these compounds in the biogenesis of mono-THF acetogenins is discussed.
On a preliminary screening, substantial leishmanicidal activity was observed for the petroleum ether and alkaloidal extracts of the stem bark of Unonopsis buchtienii, the alkaloids and sterols isolated from these were studied. Of the alkaloids, liriodenine exhibited the highest activity against Leishmania major and L donovani (IC100 = 3.12 micrograms/mL). On the other hand, O-methylmoschatoline and the petroleum ether extract without alkaloids showed an interesting in vitro activity against Trypanosoma brucei with an IC100 of 6.25 micrograms/mL. The highest cytotoxic activities were found with the petroleum ether extracts without alkaloids and with all alkaloids isolated (IC50 < 9 micrograms/mL for Vero cell line).
Bioactivity-directed fractionation of the MeOH extract of the stem barks of Rollinia emarginata resulted in the isolation of six compounds, four acetogenins, rolliniastatin-1, sylvaticin, squamocin, and rollidecin B, one lignan, lirioresinol B, and an oxoaporphine, liriodenin. Their structures were determined by spectroscopic analysis and their in vitro leishmanicidal and trypanocidal properties are reported.
A series of quinones (3a-i, 4-9, 11) and aromatic compounds (2a, 2d, 2g) containing the thiophene ring were tested in vitro against the trypomastigote form of Trypanosoma cruzi and the promastigote forms of Leishmania. The quinones 3a-i, 4, 5a, b, 6 and 9 having the thiophene ring fused to a quinone nucleus were the most active members of the series. The electron affinities of the benzo[b]thiophene-4,7-quinones 3, evaluated by their LUMO energies and halfwave potentials, are reported.
Eleven bisbenzylisoquinoline (BBIQ) alkaloids were studied for in vitro trypanocidal activity against trypomastigote forms of the Y strain of Trypanosoma cruzi. The inhibitory activity of these compounds against trypanothione reductase (TR), a target enzyme for chemotherapy against Chagas disease, was also studied. Six BBIQ alkaloids (antioquine, cepharanthine, daphnoline, limacine, cycleanine and (-) curine) displayed a 50% lethal concentration (LC50) against T. cruzi of less than 100 microM. Daphnoline and curine, with LC50 values of 10 microM, are attractive for further investigation as potential anti-Chagasic drugs. Kinetic analyses suggested the BBIQ alkaloids are mixed inhibitors of TR. These compounds are reasonably potent inhibitors of TR; the best TR inhibitor, cepharanthine, had an IC50 of 15 microM, which is in the same order of magnitude as its LC50 against T. cruzi. The similar magnitudes of the IC50 and LC50 values suggest that inhibition of TR could contribute to the trypanocidal activity exhibited by the BBIQ alkaloids.
Three secondary metabolites isolated from Chilean lichens, (+) usnic acid, pannarine and 1'-chloropannarine, were tested against promastigotes forms of three strains of Leishmania ssp. Pannarine and 1'-chloropannarine exhibited in vitro activity at 50 micrograms/ml and (+) usnic acid at 25 micrograms/ml. BALB/c mice infected with Leishmania amazonensis were treated 4 weeks post-infection with (+) usnic acid by subcutaneous or oral routes for 15 days at 25 mg/kg or by five intralesional injections at interval of 4 days at 25 mg/kg of body weight. The reference drug, N-methylglucamine antimonate (Glucantime), was administered by subcutaneous injections (regimens of 28 mg of pentavalent antimony) for 15 days. The subcutaneous and oral treatments with (+) usnic did not produce any effect, but by intralesional administration we observed a significant effect that reduced by 43.34% the weight lesions and by 72.28% the parasites loads in infected footpads.
From the hexanic extract of roots of Annona haematantha an alpha,beta-unsaturated delta-lactone was isolated and identified as argentilactone. This compound exhibited in vitro activity against various strains of Leishmania ssp. at 10 micrograms/ml. BALB/c mice infected with Leishmania amazonensis were treated four weeks after infection with argentilactone by oral or subcutaneous routes for 14 days at 25 mg/kg daily. The reference drug, N-methylglucamine antimonate, was administered by subcutaneous injections at 100 mg/kg for 14 days. In these conditions, argentilactone showed the same efficacy as the reference drug, reducing by 96% the parasite loads in the lesion and by 50% the parasite burden in spleen.
The composition of essential oils from two muña, Bolivian medicinal plants, derived from Minthostachys andina and Hedomea mandonianum, were analyzed by gas chromatography/mass spectrometry. Major differences were observed in their chemical composition. Pulegone was the major component of H. mandonianum oil (44.6%) and M. andina oil (25.5%); menthone and isomenthone were around 33% of these oils. Differences were also observed in their insecticidal activity against the Chagas' disease vector, Rhodnius neglectus or Triatoma infestans bugs exposed on impregnated oil filter papers. While M. andina oil showed 30%-50% of mortality in both triatomine species after a period of 1 week, H. mandonianum oil did not show any insecticidal activity. Nevertheless, both species had insecticidal activity (33.3% and 50%) when oils were topically applied. The significance of these results is discussed in relation to the variability of the chemical composition and their potential use in Chasgas' disease vector control.
Two new prenylated quinones, piperogalone (1) and galopiperone (2), and a new prenylated dihydroquinone, hydropiperone (3), were isolated from Peperomia galioides H.B.K (Piperaceae). Hydropiperone exhibited potent antiparasitic activity against three species of Leishmania.
The trunk bark and roots of Annona spinescens have been investigated for their alkaloid content. Two new berbine alkaloids, pessoine (1) and spinosine (2), have been isolated from the bark, and their structures were elucidated by spectroscopic methods. Eight known isoquinoline alkaloids were also obtained. The trypanocidal and antileishmanial activities of these isolated compounds have been investigated.