Antibacterial Sesquiterpene Lactones from Kaunia lasiophthalma.

Phytochemical study of the species Kaunia lasiophthalma enabled the isolation of three undescribed and three known guaianolide-type sesquiterpene lactones, and one new benzofuran. The bioguided fractionation methodology was successful in detecting antimicrobial metabolites against Staphylococcus aureus strains and permitted the description of undescribed guaianolide-type sesquiterpene lactones with substitution patterns matching all those described in the Oxylobinae subtribe.

Selective extraction of antimicrobial agents from Jodina rhombifolia by supercritical fluid carbon dioxide: phytochemical profile.

The goals of this study were to determine the phytochemical profile of Jodina rhombifolia and to evaluate the ability of supercritical fluids (ScFCO2) to selectively extract the metabolites responsible for the bioactivity. This species has simple aromatic compounds and lignan monomers, as well as glycerides containing epoxidized saturated fatty acids. Regarding the extraction by ScFCO2, the extracts showed a higher antimicrobial activity against human pathogenic strains, with respect to the ethanolic extracts obtained from plant residues after extraction by ScFCO2. Furthermore, the bioactive compounds were concentrated in just 1% P/P of the weight of the dry plant material. Extraction by ScFCO2 was carried out under different conditions of pressure and temperature, with the best results being obtained at 30 °C and 30 MPa. The results obtained demonstrate the advantages of ScFCO2 extractions over classical solvent extractions, in terms of improved safety and the ability to selectively extract the compounds of interest.

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.

Prenylflavonoids from Flourensia fiebrigii.

Three compounds: (2S)-8-(3''-methylbut-2''-enyl)-7,3',4'-trihydroxyflavanone, (2S)-8-(3''-methyl-4''-hydroxy-but-2''-enyl)-7,3',4'-trihydroxyflavanone and (2S)-8-(3''-methyl-4''-hydroxy-but-2''-enyl)-5,3',4'-trihydroxy-7-methoxyflavanone, along with five previously known compounds, were isolated from the aerial parts of Flourensia fiebrigii. Their structures were elucidated by application of various spectroscopic methods, including 1D and 2D NMR techniques.

Constituents of two Flourensia species.

The MeOH extract of aerial parts of Flourensia riparia Grisebach (Asteraceae) afforded a sesquiterpene lactone, 4beta-hydroxy-4,10alpha-dimethyl-7alphaH,8alphaH-eudesman-11-ene-8,12-olide, together with septuplinolide, its isomer at positions C-5 and C-10. In addition, known flavonoids, p-hydroxyacetophenone derivatives, carabrone and isoalantolactone were identified. Three known flavonoids and a benzofuran were isolated from Flourensia campestris Wedd.