Metabolic constituents of grapevine and grape-derived products

The numerous uses of the grapevine fruit, especially for wine and beverages, have made it one of the most important plants worldwide. The phytochemistry of grapevine is rich in a wide range of compounds. Many of them are renowned for their numerous medicinal uses. The production of grapevine metabolites is highly conditioned by many factors like environment or pathogen attack. Some grapevine phytoalexins have gained a great deal of attention due to their antimicrobial activities, being also involved in the induction of resistance in grapevine against those pathogens. Meanwhile grapevine biotechnology is still evolving, thanks to the technological advance of modern science, and biotechnologists are making huge efforts to produce grapevine cultivars of desired characteristics. In this paper, important metabolites from grapevine and grape derived products like wine will be reviewed with their health promoting effects and their role against certain stress factors in grapevine physiology

Free radicals properties of gamma-irradiated penicillin-derived antibiotics: piperacillin, ampicillin, and crystalline penicillin

The aim of this work was to determine the concentrations and properties of free radicals in piperacillin, ampicillin, and crystalline penicillin after gamma irradiation. The radicals were studied by electron paramagnetic resonance (EPR) spectroscopy using an X-band spectrometer (9.3 GHz). Gamma irradiation was performed at a dose of 25 kGy. One- and two-exponential functions were fitted to the experimental data, in order to assess the influence of the antibiotics’ storage time on the measured EPR lines. After gamma irradiation, complex EPR lines were recorded confirming the presence of a large number of free radicals formed during the irradiation. For all tested antibiotics, concentrations of free radicals and parameters of EPR spectra changed with storage time. The results obtained demonstrate that concentration of free radicals and other spectroscopic parameters can be used to select the optimal parameters of radiation sterilization of β-lactam antibiotics. The most important parameters are the constants τ (τ(1(A),(I)) and τ(2(A),(I))) and K (K(0(A),(I)), K(1(A),(I)), K(2(A),(I))) of the exponential functions that describe free radicals decay during samples storage

Radiostérilisation des médicaments. Intérêt de la résonance paramagnétique électronique en dosimétrie

Nous présentons ici des résultats concernant l'étude par Résonance Paramagnétique Electronique (R.P.E.) des effets de l'irradiation par rayonnement gamma en vue de la radiostérilisation de 5 molécules : deux antiparasitaires nitroimidazolés (Tinidazole et Secnidazole), deux antiparasitaires nitrofuranes (Furaltadone et Furazolidone) et un antibactérien phénicolé (Chloramphénicol). Nous effectuons la modélisation par une fonction polynomiale des courbes de dosimétrie dans un intervalle de 0 à 50 kGy. L’importance de la recombinaison des radicaux libres dans le temps est étudiée dans le cas du chloramphénicol

Radiolyse gamma de trois antiparasitaires : metronidazole, ornidazole et ternidazole

Ce travail présente les premières observations RPE et CLHP relatives à trois nitroimidazoles irradiés en phase solide. Les radicaux formés lors de la radiolyse du métronidazole et de l'ornidazole sont stables contrairement à ceux du ternidazole. Les analyses chromatographiques montrent la formation de produits de radiolyse. A 25 kGy, la dégradation est faible