DIVERSIDAD GENÉTICA Y MEJORAMIENTO DE PLANTAS MEDICINALES:

Lepidium sensu stricto (s.s.) (Brassicaceae) (ca. 150 species) is distributed worldwide with endemic species on every continent.  It is represented in Australia and New Zealand by 19 and seven native species, resp.  In the present study we used a nuclear ribosomal internal transcribed spacer (ITS) phylogeny in comparison with a cpDNA phylogeny to unravel the origin of Australian/New Zealand species.  Although phylogenetic relationships within Lepidium s.s. were not fully resolved, the cpDNA data were in agreement with a Californian origin of Lepidium species from Australia/New Zealand.  Strongly conflicting signals between the cp- and nuclear DNA phylogenetic anal. clearly indicated hybridogenous genomic constitution of Australian Lepidium s.s. species: All 18 studied Australian/New Zealand Lepidium s.s. species examd. shared a Californian cpDNA type.  While eleven Australian/New Zealand species appeared to harbor a Californian ITS type, a group of seven species shared a South African ITS type.  This pattern is most likely explained by two trans-oceanic dispersals of Lepidium from California and Africa to Australia/New Zealand and subsequent hybridization followed by homogenization of the ribosomal DNA either to the Californian or South African ITS type in the two different lineages.  Calibration of our mol. trees indicates a Pliocene/Pleistocene origin of Lepidium in Australia/New Zealand.  Low levels of cpDNA and ITS sequence divergence and unresolved topologies within Australian/New Zealand species suggest a rapid and recent radiation of Lepidium after the hybridization event.  This coincides with dramatic climatic changes in that geol. epoch shaping the compn. of the vegetation.  

PARTE UTILIZADA= Used part: Hoja, flor.

ACCIÓN FARMACOLÓGICA= Pharmacological action: Diaforético, diurético, emoliente y vulnerario.

COMPOSICIÓN QUÍMICA= Chemical composition: P-Methoxybenzylisothiocyanate (I) was isolated from Lepidium bonariense and found to be responsible for the antimicrobial and anti-STD (sexually transmitted disease) activity of the plant. MIC detns. were conducted for I on Haemophilus ducreyi, Neisseria gonorrheae, Candida albicans, Bacillus subtilis, Micrococcus luteus, Staphylococcus aureus, Enterobacter sp., Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. I was active against all the tested organisms. An in vitro cellular toxicity assay showed that at 100 uM (17.9 ug/mL) I is not toxic to living cells.

ZONA GEOGRÁFICA= Geografical zone: Uruguay.

Origin
“Cariri Paraibano”, Brazil
Medicinal indication
As tonic and against anemias and tuberculosis: Fresh leaves

1) GONZALEZ, Matías ; LOMBARDO, Atilio ; VALLARINO, Aida. Plantas de la medicina vulgar del Uruguay. Montevideo : Talleres Gráficos, 1937, p.139.

2) SWART, Henk; VAN DYK, Sandra; Malan, SAREL, F. The activity of p-methoxybenzylisothiocyanate against Neisseria gonorrhoeae, Haemophilus ducreyi, and other microorganisms. Bioorganic & Medicinal Chemistry Letters. 2002, vol.12, nº17, p.2435-2437.
 
3)  MUMMENHOFF, Klaus, et al. Molecular evidence for bicontinental hybridogenous genomic constitution in  Lepidium  sensu stricto (Brassicaceae) species from Australia and New Zealand.  American Journal of Botany. 2004, vol.91, nº2, p.254-261.

4) M.F. Agra; et al/ Medicinal and poisonous diversity of the flora of “Cariri Paraibano”, Brazil/ Journal of Ethnopharmacology 111 (2007), p. 388.