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Cyclic voltammetric analysis of 2-styrylchromones: Relationship with the antioxidant activity

Publication . Gomes, Ana Sara; Fernandes, Eduarda; Garcia, M. Beatriz; Silva, Artur; Pinto, Diana; Santos, Clementina M.M.; Cavaleiro, José; Lima, José Costa

2-Styrylchromones (2-SC) are a chemical family of oxygen heterocyclic compounds, vinylogues of flavones (2-phenylchromones), whose occurrence in nature has been reported. Recently, several 2-SC derivatives were demonstrated to have antioxidant properties, namely, xanthine oxidase inhibition, hepatoprotection against pro-oxidant agents in cellular and non-cellular systems and scavenging activity against reactive oxygen and reactive nitrogen species (ROS and RNS). Considering these antioxidant properties, it may be hypothesised that the electrochemical redox behaviour of 2-SC contributes significantly to their activity. To test this hypothesis, the electrochemical behaviour of different 2-SC was studied, together with a number of flavonoids with well-known antioxidant activities, by cyclic voltammetry, and the results correlated to their ability to scavenge ROS and RNS. The results obtained showed that 2-SC with a catecholic B-ring have a low oxidation peak potential corresponding to the oxidation of the 30,40-OH (catechol) moiety. The compounds with a phenolic B-ring have a common peak, with oxidation potential values of about +0.4/+0.5 V versus Ag/AgCl, corresponding to the oxidation of the 40-OH. The oxidation of the hydroxyl substituents in the A-ring generated peaks of higher potentials (+0.7/+0.8 V vs Ag/AgCl). The results from the scavenging assays were in agreement with those obtained from the cyclic voltammetry, that is, higher scavenging effects corresponded to lower values of oxidation potentials, with significant correlation coefficients. The values obtained for the studied flavonoids are in accordance with the literature, and reflect their relative antioxidant activity, when compared to the studied 2-SC. Thus, in this family of compounds, oxidation potentials obtained by cyclic voltammetry seem to be applicable as a general indicator of radical scavenging activity.

2008Journal article

Open access

Inhibition of NF-kB activation and cytokines production in THP-1 monocytes by 2-styrylchromones

Publication . Gomes, Ana Sara; Capela, João Paulo; Ribeiro, Daniela; Freitas, Marisa; Silva, Artur; Pinto, Diana; Santos, Clementina M.M.; Cavaleiro, José; Lima, José L.F.C.; Fernandes, Eduarda

Nuclear factor kappa B (NF-kB) is one of the most important transcription factors whose modulation triggers a cascade of signaling events, namely the expression of many cytokines, enzymes, chemokines, and adhesion molecules, some of which being potential key targets for intervention in the treatment of inflammatory conditions. The 2-styrylchromones (2-SC) designation represents a well-recognized group of natural and synthetic chromones, vinylogues of flavones (2-phenylchromones). Several 2-SC were recently tested for their anti-inflammatory potential, regarding the arachidonic acid metabolic cascade, showing some motivating results. In addition, several flavones with structural similarities to 2-SC have shown NF-kB inhibitory properties. Hence, the aim of the present work was to continue the investigation on the interference of 2-SC in inflammatory pathways. Herein we report their effects on lipopolysaccharide (LPS)-induced NF-kB activation and consequent production of proinflammatory cytokines/chemokine, using a human monocytic cell line (THP-1). From the twelve 2-SC tested, three of them were able to significantly inhibit the NF-kB activation and to reduce the production of the proinflammatory cytokines/chemokine. The compound 3',4',5-trihydroxy-2- styrylchromone stood up as the most active in both assays, being a promising candidate for an anti-inflammatory drug.

2015Journal article

Open access

Anti-inflammatory potential of 2-styrylchromones regarding their interference with arachidonic acid metabolic pathways

Publication . Gomes, Ana Sara; Fernandes, Eduarda; Silva, Artur; Pinto, Diana; Santos, Clementina M.M.; Cavaleiro, José; Lima, José Costa

Cyclooxygenases (COXs) are the key enzymes in the biosynthesis of prostanoids. COX-1 is a constitutive enzyme while the expression of COX-2 is highly stimulated in the event of inflammatory processes, leading to the production of large amounts of prostaglandins (PGs), in particular PGE2 and PGI2, which are pro-inflammatory mediators. Lipoxygenases (LOXs) are enzymes that produce hydroxy acids and leukotrienes (LTs). 5-LOX metabolizes arachidonic acid to yield, among other products, LTB4, a potent chemoattractantmediator of inflammation. The aim of the present work was to evaluate the anti-inflammatory potential of 2-styrylchromones (2-SC), a chemical family of oxygen heterocyclic compounds, vinylogues of flavones (2-phenylchromones), by studying their COX-1 and COX-2 inhibitory capacity as well as their effects on the LTB4 production by stimulated human polymorphonuclear leukocytes (PMNL). Some of the tested 2-SC were able to inhibit both COX-1 activity and LTB4 production which makes them dual inhibitors of the COX and 5-LOX pathways. The most effective compounds in this study were those having structural moieties with proved antioxidant activity (30,40-catechol and 40-phenol substituted B-rings). This type of compounds may exhibit anti-inflammatory activity with a wider spectrum than that of classical non-steroidal anti-inflammatory drugs (NSAIDs) by inhibiting 5-LOX product-mediated inflammatory reactions, towards which NSAIDs are ineffective.

2009Journal article

Open access