No abstract

Abstract-2-Styrylchromones are a small group of naturally occurring chromones, vinylogues of flavones (2-phenylchromones). Natural and synthetic 2-styrylchromones have been tested in different biological systems, showing activities with potential therapeutic applications. In particular, the potential and hitherto understudied antioxidant behavior of these compounds has been raised as a matter of interest. Thus the present work consisted in the study of the in vitro scavenging activities for reactive oxygen species (ROS) and reactive nitrogen species (RNS) of various 2-styrylchromone derivatives and structurally similar flavonoids. Some of the studied 2-styrylchromones proved to be extremely efficient scavengers of the different ROS and RNS, showing, in some cases, IC 50 s under 1 lM. The hydroxylation pattern of 2-styrylchromones, especially in the B-ring but also in the A ring, modulates the activity of these compounds, the catecholic derivatives being the most effective scavengers. The styryl pattern also contributes to their observed outstanding antioxidant activity. In conclusion, the scavenging activities for ROS/RNS of 2-styrylchromone derivatives, here shown for the first time, provide novel and most promising compounds to be applied as antioxidants.

Flavonoids (or bioflavonoids) are naturally occurring compounds, ubiquitous in all vascular plants. These compounds have been considered to possess anti-inflammatory properties, both in vitro and in vivo. Although not fully understood, these health-promoting effects have been mainly related to their interactions with several key enzymes, signaling cascades involving cytokines and regulatory transcription factors, and antioxidant systems. The biological effects of flavonoids will depend not only on these pharmacodynamic features but also on their pharmacokinetics, which are dependent on their chemical structure, administered dose schedule and route of administration. Thus, the therapeutic outcome mediated by flavonoids will result from a complex and interactive network of effects, whose prediction require a deep and integrated knowledge of those pharmacokinetic and pharmacodynamic factors. The aim of the present review is thus to provide an integrated update on the bioavailability and biotransformation of flavonoids and the mechanisms of activity at the molecular, cellular, organ and organism levels that may contribute to their anti-inflammatory effects.