Benzofuran: A Key Heterocycle - Ring Closure And Beyond

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The benzofuranyl motif present in compounds exhibits various medicinal properties and non-drug applications. These derivatives are naturally occurring compounds or synthetic materials, which cover a broad spectrum of pharmacological activities like anti-inflammatory, anti-diabetic, anti- depressant, anti-HIV, anti-microbial, anti-proliferative, anti-convulsant, cytotoxic, analgesic, etc. Few of the commercially interesting compounds from this class are, ailanthoidol (anti-inflammatory), amiodarone, dronedarone, celivarone (anti-arrhythmic), bufuralol (muscular airways relaxant), morphine, 5-(2-aminopropyl)benzofuran; 5-APB, 6-(2-aminopropyl)benzofuran; 6-APB (CNS), rifampicin (antibiotic), etc., whereas, some of the non-drug applications are in perfumery industry (bergapten) and as tannin activators in sunscreen preparations (psoralen, 8-methoxypsoralen, and angelicin). Considering these interesting biological activities and commercial utilities, a review on the synthetic aspects of this privileged scaffold was attempted. For the benefit of natural product-based drug discovery, available sources of these derivatives, extraction process and reported biological activities have also been outlined in this review.

2-(4-Hydroxyphenyl)-5-(3-Hydroxypropenyl)-7-Methoxybenzofuran, a Novel Ailanthoidol Derivative, Exerts Anti-Inflammatory Effect through Downregulation of Mitogen-Activated Protein Kinase in Lipopolysaccharide-Treated RAW 264.7 Cells

We reported that ailanthoidol, a neolignan from Zanthoxylum ailanthoides and Salvia miltiorrhiza Bunge, inhibited inflammatory reactions by macrophages and protected mice from endotoxin shock. We examined the anti-inflammatory activity of six synthetic ailanthoidol derivatives (compounds 1-6). Among them, compound 4, 2-(4-hydroxyphenyl)-5-(3-hydroxypropenyl)-7-methoxybenzofuran, had the lowest IC50 value concerning nitric oxide (NO) release from lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Compound 4 suppressed the generation of prostaglandin (PG) E2 and the expression of inducible NO synthase and cyclooxygenase (COX)-2 induced by LPS, and inhibited the release of LPS-induced pro-inflammatory cytokines from RAW264.7 cells. The underlying mechanism of compound 4 on anti-inflammatory action was correlated with the down-regulation of mitogen-activated protein kinase and activator protein-1 activation. Compound 4 is potentially an effective functional chemical candidate for the prevention of inflammatory diseases.