María L. Uriburu

Sesquiterpene lactone variability in Parthenium hysterophorus L.

A population of Parthenium hysterophorus collected in Salta Argentina afforded two ambrosanolides, 2beta-hydroxycoronopilin and 1alpha,2beta,4beta-trihydroxypseudoguaian-6beta,12-olide, as well as five known others. Plants of the fructification from those transplanted from the Puna Argentina at 1200 m over the sea level produced hymenin.

Chemotaxonomy of Parthenium: P. Hysterophorus—P. Glomeratum

Abstract From aerial parts of five plants lots of Parthenium hysterophorus-P. glomeratum collected along 72 km in Salta Province, Argentina, seven known and four new pseudoguaianolides have been found. p -Methoxybenzoic acid was also isolated from plants growing 2500 m above sea level. The taxonomic situation of both species is discussed.

Terpenoid constituents of Viguiera tucumanensis

Abstract Two varieties of Viguiera tucumanensis , collected in two different geographical regions of Argentina, were shown to have a very close chemical constitution. They all gave the new diterpene clerod-14-ene-3α,4β,13ζ-triol. The taxonomic implications are discussed briefly.

Withanolides with Antibacterial Activity from Nicandra john-tyleriana

Eleven new withanolides (1-11) were isolated and characterized from the aerial parts of Nicandra john-tyleriana. Five of these withanolides have an unmodified skeleton (1-5), two are acnistins (6, 7), and four are withajardins (8-11). These new isolates were fully characterized using a combination of spectroscopic techniques (including multidimensional NMR) and mass spectrometry. All compounds were evaluated for their antibacterial activity against Bacillus, Enterococcus, Escherichia, Listeria, Pseudomonas, and Staphylococcus strains.