Protective effect of polydatin, a natural precursor of resveratrol, against cisplatin-induced toxicity in rats.

The aim of the present study was to evaluate the possible protective effect of polydatin (PD) on cisplatin (Cis) induced oxidative stress in rats. Totally, thirty male Wistar albino rats were fed standard rodent diet and divided into 5 equal groups: the control group (vehicle treated) was treated with physiological saline for ten days both orally and intraperitoneally (i.p.), the second group was orally treated with physiological saline and 7 mg/kg single i.p. injection of Cis on the seventh day, and third, fourth, and fifth groups were treated orally PD at 25, 50, and 100 mg/kg/day, respectively for 10 days starting seven days before Cis injection and 7 mg/kg single i.p. Cis was injected on the seventh day. Cis resulted in significant increase malondialdehyde levels and decreased glutathione levels. In addition, Cis treatment decreased superoxide dismutase and catalase activities in erythrocyte and tissues. Also, Cis treatment caused to increase DNA damage and affected serum biochemical parameters whereas slightly decreased AchE activity. However, treatment of PD resulted in reversal of Cis-induced oxidative stress, lipid peroxidation, and activities of antioxidant enzymes. In conclusion, PD has protective effect in rats against Cis-induced oxidative stress, enhances antioxidant defence mechanism, and regenerates their tissues.

Prenylated and geranylated flavonoids increase production of reactive oxygen species in mouse macrophages but inhibit the inflammatory response.

In this study, four prenylated and geranylated flavonoids, cudraflavone B (1), pomiferin (2), osajin (3), and diplacone (4), were tested for their antioxidant and anti-inflammatory effects and to identify any potential relationships between chemical structure and antioxidant or anti-inflammatory properties. The selected flavonoids were examined in cell-free models to prove their ability to scavenge superoxide radicals, hydrogen peroxide, and hypochlorous acid. Further, the ability of the flavonoids to influence the formation of reactive oxygen species in the murine macrophage cell line J774.A1 was tested in the presence and absence of lipopolysaccharide (LPS). The ability of flavonoids to inhibit LPS-induced IκB-α degradation and COX-2 expression was used as a model for the inflammatory response. The present results indicated that the antioxidant activity was dependent on the chemical structure, where the catechol moiety is especially crucial for this effect. The most potent antioxidant activities in cell-free models were observed for diplacone (4), whereas cudraflavone B (1) and osajin (3) showed a pro-oxidant effect in J774.A1 cells. All flavonoids tested were able to inhibit IκB-α degradation, but only diplacone (4) also down-regulated COX-2 expression.

Synthesis and antioxidant properties of new chromone derivatives.

Nowadays, the recognition of the benefits of antioxidants is eliciting an increasingly interest in the search for new molecules with improved activity. The aim of the present work was to search for improved reactive oxygen species (ROS) and reactive nitrogen species (RNS) scavengers by testing new structures of 2-styrylchromones (2-SC) and 3-substituted flavones, which were synthesised by the Baker-Venkataraman approach. The new compounds were also tested for their metal chelating capacity and reducing activity. The obtained results showed that the methylation of hydroxyl groups decreases the scavenging of ROS and RNS by 2-SC. The decrease in the scavenging activities was, generally, more evident when the methylation occurred in B-ring, except for O2*- and (1)O(2). On the other hand, the introduction of a substituent, either hydroxyl or methoxyl, in position 8 was sometimes favourable and others unfavourable to the scavenging activities, depending on the reactive species. In conclusion, the study of the antioxidant properties of the new 2-SC and flavones allowed establishing new structure-activity relationships and brought out, in some cases, pharmacophores with improved activity.