Progress in the Chemistry of Naturally Occurring Coumarins

Abstract

Coumarins are the largest group of 1-benzopyran derivatives found in plants. The initial member of this group of compounds, coumarin (2H-1-benzopyran-2-one), a fragrant colorless compound, was first isolated from the Tonka bean (Dipteryx odorata, family Fabaceae) in 1820. The name coumarin comes from a French term for the tonka bean, coumarou. Since the discovery of coumarin, several of its derivatives, with umbelliferone (7-hydroxycoumarin) being the most common one, have been reported from various natural sources. The families Apiaceae, Asteraceae, and Rutaceae are the three major plant sources of coumarins.Generally, these plant secondary metabolites may be classified into simple, simple prenylated, simple geranylated, furano, pyrano, sesquiterpenyl and oligomeric coumarins. Using this standard classification, this chapter aims to present an account on the advances of the chemistry of naturally occurring coumarins, as reported in the literature during the period 2013-2015.In Sect. 1, the coumarins are introduced and their generic biosynthetic route discussed briefly. In Sect. 2, the largest of the three sections, various classes of natural coumarins are detailed, with their relevant structures and the citation of appropriate references. In a concluding section, it is highlighted that during the last 3 years, more than 400 coumarins have been reported in the literature. Many of these coumarins have been re-isolations of known compounds from known or new sources, most often associated with various biological activities. However, a substantial number of coumarins bearing new skeletons, especially dimers, prenylated furanocoumarins, sesquiterpenyl, and some unusual coumarins were also reported during the period of 2013-2015.Coumarin chemistry remains one of the major interest areas of phytochemists, especially because of their structural diversity and medicinal properties, along with the wide-ranging bioactivities of these compounds, inclusive of analgesic, anticoagulant anti-HIV, anti-inflammatory, antimicrobial, antineoplastic, antioxidant, and immunomodulatory effects. Despite significant advancements in the extraction, isolation, structure elucidation and bioactivity testing of naturally occurring coumarins, only a marginal advancement has been observed recently in relation to the study of their biosynthesis.

Biodegradation of 7-Hydroxycoumarin in Pseudomonas mandelii 7HK4 via ipso-Hydroxylation of 3-(2,4-Dihydroxyphenyl)-propionic Acid

“…The compound 7-hydroxycoumarin ( 5 ), also known as umbelliferone, is one of the most abundant plant-derived secondary metabolites. It is a parent compound of other, more complex natural furanocoumarins and pyranocoumarins in higher plants [ 1 , 2 , 3 ]. In the case of plant damage, plants produce a high diversity of natural coumarins as a defense mechanism against insect herbivores as well as fungal and microbial pathogens [ 4 ].…”

Coumarin: A Natural, Privileged and Versatile Scaffold for Bioactive Compounds

“…This review is focused on the design, synthesis, bio-pharmacological evaluation, and data analysis of a large number of coumarin derivatives, mainly developed in our group, as monoamine oxidase (MAO), cholinesterase (ChE), and aromatase (AR) inhibitors, and as multitarget agents addressing neurodegenerative diseases (NDs). Coumarin derivatives studied by other groups will be also taken into account, to expand the analysis of the structure–activity relationships (SARs), but not in an extensive/comprehensive way, most of them being already quoted in a recent book [ 1 ] and exhaustive reviews [ 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 ].…”

Coumarins into Polyurethanes for Smart and Functional Materials

“…Bourgaud reviewed biosynthesis pathways in regard to natural derivatives, where the different mechanisms remain unresolved or partially clarified as a function of the type of coumarins [4]. One possible classification between different proposed subclassifications of coumarins considers simple coumarins, furanocoumarins, dihydrofurano-coumarins, pyrano-coumarins, phenyl-coumarins and bicoumarins [5][6][7]. Bourgaud reviewed biosynthesis pathways in regard to natural derivatives, where the different mechanisms remain unresolved or partially clarified as a function of the type of coumarins [4].…”