Antioxidant flavonoids and isoflavonoids from rhizomes of Iris pseudopumila.

Chromatographic separation of a methanolic extract from Iris pseudopumila rhizomes led to the isolation of two new natural compounds, irilone 4'-O-[beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranoside] and isoscutellarein 6-C-beta-D-glucopyranoside, along with 9 isoflavonoids and 4 flavonoids. Their structures were determined on the basis of spectroscopic evidence. Isolated compounds were evaluated for their antioxidant activity using the luminol-dependent chemiluminescence assay, with quercetin as a positive control.

Antibacterial and antioxidant activities in Sideritis italica (Miller) Greuter et Burdet essential oils.

Sideritis italica (Miller) Greuter et Burdet is a widespread Lamiacea in the Mediterranean region used in traditional medicine. Essential oils were antibacterial against nine ATCC and as many clinically isolated Gram-positive and Gram-negative bacterial strains. Antibacterial activity was also found against Helicobacter pylori: a dose-dependant inhibition was shown between 5 and 25 microg/ml.

Improvement of (+)-catechin inhibitory activity on human PMN respiratory burst by (+)-3-O-propionyl and (-)-3-O-valeryl substitution.

Catechins and their derivatives are abundant flavanols in the plant kingdom. Usually, catechin activity correlates with chemical structure. We hypothesized that by adding hydrophobic groups to the native catechin, we could ameliorate penetration of the cell and make the derivatives more active than native molecule in inhibiting polymorphonuclear leucocyte (PMN) oxidative burst.