Fishing antioxidant 4-hydroxycoumarin derivatives: synthesis, characterization, and in vitro assessments.

Coumarins represent a diverse class of natural compounds whose importance in pharmaceutical and agri-food sectors has motivated multiple novel synthetic derivatives with broad applicability. The phenolic moiety in 4-hydroxycoumarins underscores their potential to modulate the equilibrium between free radicals and antioxidant species within biological systems. The aim of this work was to assess the antioxidant activity of 18 4-hydroxycoumarin coumarin derivatives, six of which are commercially available and the other 12 were synthesized and chemically characterized and described herein. The 4-hydroxycoumarins were prepared by a two steps synthetic strategy with satisfactory yields. Their antioxidant potential was evaluated through three in vitro methods, two free radical-scavenging assays (DPPH• and ABTS•+) and a metal chelating activity assay. Six synthetic coumarins (4a, 4g, 4h, 4i, 4k, 4l) had a scavenging capacity of DPPH• higher than butylated hydroxytoluene (BHT) (IC50 = 0.58 mmol/L) and compound 4a (4-hydroxy-6-methoxy-2 H-chromen-2-one) with an IC50 = 0.05 mmol/L outperformed both BHT and ascorbic acid (IC50 = 0.06 mmol/L). Nine hydroxycoumarins had a scavenging capacity against ABTS•+ greater (C3, 4a, 4c) or comparable (C1, C2, C4, C6, 4g, 4l) to Trolox (IC50 = 34.34 µmol/L). Meanwhile, the set had a modest ferrous chelation capacity, but most of them (C2, C5, C6, 4a, 4b, 4h, 4i, 4j, 4k, 4l) reached up to more than 20% chelating ability percentage. Collectively, this research work provides valuable structural insights that may determine the scavenging and metal chelating activity of 4-hydroxycoumarins. Notably, substitutions at the C6 position appeared to enhance scavenging potential, while the introduction of electron-withdrawing groups showed promise in augmenting chelation efficiency.

Coumarins derivatives and inflammation: Review of their effects on the inflammatory signaling pathways.

Natural and synthetic coumarins have been extensively described in the literature as effective drugs with several pharmacological activities. Many valuable publications have shown the anti-inflammatory potential of these compounds suggesting that coumarins could be an interesting scaffold for developing new therapeutic anti-inflammatory agents. However, despite the continuous efforts of research in this field, no major breakthrough was yet achieved and only a few coumarin-like drugs are commercially available. In the present article, we reviewed the most relevant studies conducted in the last two decades (2000-2021) and presenting evidence for the anti-inflammatory mechanisms of coumarins. The review provides a comprehensive survey of scientific research revealing through multiple in vitro and in vivo models the effect of natural and synthetic coumarins on components of the Toll-like receptors (TLR), Janus Kinase/Signal Transducer and Activator of Transcription (JAK/STAT), Inflammasomes, mitogen-activated protein kinase (MAPK), nuclear factor- κ-light-chain-enhancer of activated B cells (NF- κB) and transforming growth factor-ß/small mothers against decapentaplegic (TGF-ß/SMAD) pathways.