Identification of bioactive compounds from Fraxinus angustifolia extracts with anti- NADH oxidase activity of bovine milk xanthine oxidoreductase.

Fraxinus angustifolia leaves and bark are used in traditional medicine against various inflammatory-related pathologies incumbent to reactive oxygen species (ROS) generation by the NADH oxidase activity of enzymes such as xanthine oxidoreductase (XOR). This study was designed to investigate the in vitro and in vivo inhibitory activities of this enzyme by Fraxinus angustifolia extracts. The leaf organic phase of ethyl acetate (LFA) and its bark aqueous counterpart (BFA) showed the strongest anti-NADH oxidase activity in vitro (IC50 = 38.51 and 42.04 µg mL-1, respectively). They consequently suppressed superoxide generation both enzymatically (53% and 19%, respectively) and nonenzymatically (34% and 19%, respectively). These results were corroborated in vivo, with high antiNADH oxidase potential of the leaves and bark extracts (75.32% and 51.32%, respectively) concomitant with moderate hypouricemic activities (36.84% and 38.59%, respectively). Bio-guided fractionation led to the identification, by LC-DAD-MS/MS, of esculin and calcelarioside in bark and kaempferol glucoside in leaves as the main compounds responsible for the anti-NADH oxidase activity of XOR. These results plead in favor of the use of F. angustifolia as a source of potentially interesting therapeutic substances.

Unusual compounds from Galium mollugo and their inhibitory activities against ROS generation in human fibroblasts.

Three unusual dioxatricyclodecenone compounds, mollugoside A, E-mollugoside B and Z-mollugoside B and, together with known flavonoids, were isolated from the aerial parts of Galium mollugo collected in north-eastern Algeria. Their structures were elucidated by analysis of spectroscopic data, including 1D and 2D NMR. Flavonoids and mollugoside A significantly reduced reactive oxygen species (ROS) generation in human fibroblasts.

Bioactive stilbenes from Vitis vinifera grapevine shoots extracts.

BACKGROUND: Viticultural residues from commercial viticultural activities represent a potentially important source of bioactive stilbenes such as resveratrol. The main aim of the present study was therefore to isolate, identify and perform biological assays against amyloid-ß peptide aggregation of original stilbenes from Vitis vinifera shoots. RESULTS: A new resveratrol oligomer, (Z)-cis-miyabenol C (3), was isolated from Vitis vinifera grapevine shoots together with two newly reported oligostilbenes from Vitis vinifera shoots, vitisinol C (1) and (E)-cis-miyabenol C (2), and six known compounds: piceatannol, resveratrol, (E)-ε-viniferin (trans-ε-viniferin), ω-viniferin, vitisinol C and (E)-miyabenol C. The structures of these resveratrol derivatives were established on the basis of detailed spectroscopic analysis including nuclear magnetic resonance experiments. All the newly reported compounds were tested for their anti-aggregative activity against amyloid-ß fibril formation. Vitisinol C was found to exert a significant activity against amyloid-ß aggregation. CONCLUSION: Vitis vinifera grapevine shoots are potentially interesting as a source of new bioactive stilbenes, such as vitisinol C.