DIVERSIDAD GENÉTICA Y MEJORAMIENTO DE PLANTAS MEDICINALES:

The best conditions for callus growth from A. tenuifolia leaf explants in vitro was pH 7, 2-3% sucrose, and 12 Wm-2 light. Addn. of nitrogen sources and plant hormones stimulated prodn. of the following psilostachyinolides: psilostachyin, psilostachyin B, psilostachyin C, and altamisin. Psilostachyinolides were produced in higher levels in the callus than in the whole plant. 

ÚLTIMOS AVANCES EN LA QUÍMICA Y ACTIVIDADES BACTERIOLÓGICAS EN LAS PLANTAS MEDICINALES

1) Bioassay-guided fractionation of the org. ext. of Ambrosia tenuifolia Sprengel (Asteraceae) led to the isolation of two bioactive sesquiterpene lactones with significant trypanocidal and leishmanicidal activities.  By spectroscopic methods (1H- and 13C-NMR, distortionless enhancement by polarization transfer, correlated spectroscopy, heteronuclear multiple-quantum coherence, electron impact-mass spectrometry, and IR spectroscopy), these compds. were identified as psilostachyin and peruvin.  Both compds. showed a marked in vitro trypanocidal activity against Trypanosoma cruzi epimastigotes with 50% inhibitory concn. (IC50) values of less than 2 mg/mL.  Psilostachyin exerted a significant in vitro activity against the trypomastigote forms of T. cruzi (IC50, 0.76 mg/mL) and was selected for in vivo testing.  Psilostachyin-treated mice had a survival of 100% and lower parasitemia values than control mice.  Both compds. were also tested on Leishmania sp. promastigotes: psilostachyin (IC50, 0.12 mg/mL) and peruvin (IC50, 0.39 mg/mL) exerted significant leishmanicidal activities.  This is the first time that the trypanocidal and leishmanicidal activities of these compds. have been reported.  The selectivity index (SI) was employed to evaluate the cytotoxic effect of lactones on T lymphocytes.  Although the SIs of both compds. were high for T. cruzi epimastigotes, psilostachyin was more selective against trypomastigotes (SI, 33.8) while peruvin showed no specificity for this parasite.  Both compds. presented high selectivity for Leishmania spp.  The results shown herein suggest that psilostachyin and peruvin could be considered potential candidates for the development of new antiprotozoal agents against Chagas' disease and leishmaniasis.  

2) The in vitro antimalarial, trypanocidal and leishmanicidal activities and the chem. compn. of Ambrosia tenuifolia and A. scabra essential oils were investigated.  The oils, obtained by hydrodistn. of the aerial parts, showed significant antimalarial activity against the chloroquine sensitive (F32) and the chloroquine resistant (W2) strains of Plasmodium falciparum with 50% inhibitory concn. (IC50) values ranged from 2.8 to 7 mg/mL.  Against Trypanosoma cruzi epimastigotes, only A. tenuifolia exerted slight activity (IC50 = 59.7 mg/mL).  None of the essential oils showed toxicity towards Leishmania mexicana.  Cytotoxicity for murine T-lymphocytes was compared with the parasiticidal activity by using the selectivity index (SI) ratio.  The chem. compn. of A. tenuifolia and A. scabra essential oils was analyzed by GC-FID-MS.  Thirty-eight and twenty-four compds. were identified in A. tenuifolia and A. scabra, resp.  The major constituents of A. tenuifolia oil were germacrene D (22.9%) and bicyclogermacrene (14.2%), while the oil of A. scabra contained limonene (22.0%), caryophyllene oxide (13.8%) and (E)-caryophyllene (13.5%).  This is the first time that the antiprotozoal activity of both oils and the chem. compn. of A. scabra essential oil have been reported.  

PARTE UTILIZADA= Used part: Ramas floriferas, sumidades floridas. 

ACCIÓN FARMACOLÓGICA= Pharmacological action: Estimulante, anticatarral. 

COMPOSICIÓN QUÍMICA= Chemical composition: The water distd. leaf oils of the two Mauritian medicinal plants A. verlotiorum Lamotte and A. tenuifolia Sprengel, were examd. by GC and GC/MS. The A. verlotiorum oil which was obtained in 1.7% yield contained 22 identified constituents representing 77.8% of the oil with germacrene D (23.6%) as the major component. A. tenuifolia (1.32% yield) contained 32 components representing 99.2% of the oil with alpha-thujone as the major component (79.3%). 

ZONA GEOGRÁFICA= Geografical zone: S de Brasil, Paraguay, S. de Argentina. 

1) TOURSARKISSIAN, Martín. Plantas medicinales de Argentina : sus nombres botánicos, vulgares, usos y distribución geográfica . Buenos Aires : Hemisferio Sur, 1980, p.26.

2) GURIB-FAKIM, Ameenah. Volatile constituents of the leaf oil of Artemisia verlotiorum Lamotte and Ambrosia tenuifolia Sprengel (Syn.: Artemisia psilostachya auct. non L.). Journal of Essential Oil Research.1996, vol.8, nº5, p.559-561.
     
3) GOLENIOWSKI, M. E.; SILVA, G. L. Ambrosia tenuifolia Spreng (altamisa): in vitro culture and the production of psilostachyinolides. Biotechnology in Agriculture and Forestry.(Medicinal and Aromatic Plants). 1993, vol.24, p.41-53.
     
4) SULSEN, Valeria P., et al. Trypanocidal and leishmanicidal activities of sesquiterpene lactones from  Ambrosia   tenuifolia  Sprengel (Asteraceae). Antimicrobial Agents and Chemotherapy. 2008, vol.52, nº7, p.2415-2419.
     
5)  SULSEN, Valeria P., et al. In vitro antiprotozoal activity and chemical composition of  Ambrosia   tenuifolia  and A. scabra essential oils. Natural Product Communications. 2008, vol.3, nº4, p.557-562.