The EU environmental policy is challenged by current international development (withdrawal of the US from the Paris climate accord, melting of the Arctic, changes in climate, extreme weather events), the sustainable development policy agenda and also by public pressure. The interest of the public in the environmental policy is not only reflected in the Eurobarometer polls, the increase of green parties in 2019 EP elections, but it is also present in the very first European Citizens’ Initiative, the environmentally oriented Right2Water initiative, which had been presented to the Commission in 2013. Following the need to reflect upon the current problems and challenges, the scope of European Environmental Policy (EEP) has broadened from traditional direct environmental challenges, such as access to clean water, clean air, maintaining biodiversity also to other areas connected to current challenges as the climate change and sustainable development and into practical implementation in particular internal and external policies – including trade policy, competition policy or public procurement. Following analysis is focused on the position of the green agenda and EEP transfer to legislation in public procurement on European level.
The group of 21 novel semi-synthetic derivatives of quercetin was screened for the antiradical efficiency in a DPPH assay. The initial fast absorbance decrease of DPPH, corresponding to the transfer of the most labile H atoms, was followed by a much slower absorbance decline representing the residual antiradical activity of the antioxidant degradation products. Initial velocity of DPPH decolorization determined for the first 75-s interval was used as a marker of the antiradical activity. Application of the kinetic parameter allowed good discrimination between the polyphenolic compounds studied. The most efficient chloronaphthoquinone derivative (compound Ia) was characterized by antiradical activity higher than that of quercetin and comparable with that of trolox. Under the experimental conditions used, one molecule of Ia was found to quench 2.6±0.1 DPPH radicals.
Aldose reductase inhibitory activity and antioxidant capacity of pomegranate extracts
The pomegranate, Punica granatum L., has been the subject of current interest as a medicinal agent with wide-ranging therapeutic indications. In the present study, pomegranate ethanolic seed and hull extracts were tested, in comparison with a commercial sample, for the inhibition of aldose reductase, an enzyme involved in the etiology of diabetic complications. In vitro inhibition of rat lens aldose reductase was determined by a conventional method. Pomegranate ethanolic hull extract and commercial pomegranate hull extract exhibited similar aldose reductase inhibitory activity characterized by IC50 values ranging from 3 to 33.3 μg/ml. They were more effective than pomegranate ethanolic seed extract with IC50 ranging from 33.3 to 333 μg/ml. Antioxidant action of the novel compounds was documented in a DPPH test and in a liposomal membrane model, oxidatively stressed by peroxyl radicals. All the plant extracts showed considerable antioxidant potential in the DPPH assay. Pomegranate ethanolic hull extract and commercial pomegranate hull extract executed similar protective effects on peroxidatively damaged liposomal membranes characterized by 10 < IC50 < 100 μg/ml. Pomegranate ethanolic seed extract showed significantly lower antioxidant activity compared to both hull extracts studied. Pomegranate extracts are thus presented as bifunctional agents combining aldose reductase inhibitory action with antioxidant activity and with potential therapeutic use in prevention of diabetic complications.
Cemtirestat, 3-mercapto-5H-[1,2,4]-triazino[5,6-b]indole-5-acetic acid was recently designed and patented as a highly selective and efficient aldose reductase inhibitor endowed with antioxidant activity. The aim of the present study was to assess the general toxicity of cemtirestat using in silico predictions, in vitro and in vivo assays. ProTox-II toxicity prediction software gave 17 “Inactive” outputs, a mild hepatotoxicity score (0.52 probability) along with a predicted LD50 of 1000 mg/kg. Five different cell lines were used including the immortalized mouse microglia BV-2, the primary human fibroblasts VH10, the insulinoma pancreatic β-cells INS-1E, the human colon cancer cells HCT116 and the human immortalized epithelial endometrial cell lines HIEEC. In contrast to the clinically used epalrestat, cemtirestat showed remarkably low cytotoxicity in several different cell culture viability tests such as MTT proliferation assay, neutral red uptake, BrdU incorporation, WST-1 proliferation assay and propidium iodide staining followed by flow cytometry. In a yeast spotting assay, the presence of cemtirestat in incubation of Saccaromyces cerevisiae at concentrations as high as 1000 µM did not affect cell growth rate significantly. In the 120-day repeated oral toxicity study in male Wistar rats with daily cemtirestat dose of 6.4 mg/kg, no significant behavioral alterations or toxicological manifestations were observed in clinical and pathological examinations or in hematological parameters. In summary, these results suggest that cemtirestat is a safe drug that can proceed beyond preclinical studies.